JPH07322219A - Transmitter - Google Patents

Abstract

PURPOSE:To form the transmission/reception system in which much more information at the same frequency band is sent by solving it that the impossibility of transmission information quantity cannot be increased when a frequency band is limited in the transmitter sending a digital signal. CONSTITUTION:A modulator 4 implementing m-value QAM modulation in a transmitter 1 assigns n-value data of a 1st data string to a signal point group formed by grouping signal points of n-value 1st data string and p-value 2nd and 3rd data strings on a space diagram and sends a modified m-value QAM modulation signal. A demodulator 25 of a 1st receiver 23 demodulates the n- value 1st data string, a 2nd receiver 33 demodulates the 1st and 2nd data strings, a 3rd receiver 43 demodulates the 1st, 2nd and 3rd data strings, and even in the case of the receiver having only n-value demodulation capability of n<m demodulates data of the n-value 1st data string when the m-value modified multi-value modulation wave is received in the transmitter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission device for transmitting a digital signal by modulating a carrier wave.

[0002]

2. Description of the Related Art In recent years, digital transmission devices have been used in various fields. In particular, the progress of digital video transmission technology is remarkable.

Above all, a digital TV transmission system has recently been receiving attention. At present, the digital TV transmission device is only partially put into practical use for relaying between broadcasting stations. However, in the near future, it is planned to expand to terrestrial broadcasting and satellite broadcasting, and is being studied in various countries.

In order to meet the increasing demands of consumers, H
It is necessary to improve the quality and quantity of the content of broadcasting services such as DTV broadcasting, PCM music broadcasting, information broadcasting and FAX broadcasting. In this case, it is necessary to increase the amount of information within the limited frequency band of TV broadcasting. The amount of information that can be transmitted in this band will increase in accordance with the technological limits of that era. Therefore, ideally, it is desirable to be able to change the receiving system according to the times and expand the information transmission amount.

However, from the viewpoint of broadcasting, publicity is important and it is important to secure vested rights of all viewers for a long period of time. When starting a new broadcasting service, it is a necessary condition that the existing receiver or receiver can enjoy the service. It can be said that the compatibility of receivers or receivers and the compatibility of broadcasting between past and present, and new and old broadcasting services of the present and future are the most important.

[0006] New transmission standards such as digital TV broadcasting standards that will appear in the future are required to have expandability of the amount of information that can meet future social demands and technological progress, and compatibility and compatibility with existing receiving devices. Has been.

[0007] Here, the transmission system of the TV broadcasting proposed so far will be described from the viewpoint of expandability and compatibility.

First, N is adopted as a satellite broadcasting system of digital TV.
A method has been proposed in which a signal obtained by compressing a TSC-TV signal to about 6 Mbps is multiplexed by a TDM method using 4-level PSK modulation, and a single transponder broadcasts a 4-20 channel NTSC TV program or a 1-channel HDTV. As a terrestrial broadcasting system of HDTV, a system of compressing a 1-channel HDTV video signal into data of about 15 Mbps and performing a terrestrial broadcasting using a 16 or 32 QAM modulation system is under study.

In the satellite broadcasting system, the currently proposed broadcasting system simply uses the conventional transmission system and uses the NTSC frequency band for several channels for one-channel HDTV program broadcasting. Therefore, HDT
There has been a problem that several channels of NTSC programs cannot be received and broadcast during the V program broadcast time. NTSC and H
It can be said that there was no compatibility or compatibility between the receiver and the receiver for DTV broadcasting. Moreover, it can be said that the expandability of the information transmission amount, which is required in accordance with future technological progress, was not considered at all.

Next, the conventional HDT currently being studied
The terrestrial broadcasting system of V uses HDTV signals in 16QAM and 32Q.
It is just broadcasted as it is in a conventional modulation method such as AM. In the case of existing analog broadcasting, even in the broadcasting service area, there are always areas where reception is poor such as building shadows, lowlands, and interference with adjacent TV stations.
In such an area, although the image quality is deteriorated in the case of the existing analog broadcasting, the video can be reproduced and the TV program can be viewed. However, the conventional digital TV broadcasting system has a serious problem that no video can be reproduced and a TV program cannot be viewed at all in such an area. This is an issue that includes the essential problems of digital TV broadcasting and may be fatal to the spread of digital TV broadcasting. This is because the signal points of the conventional modulation method such as QAM are arranged at equal intervals. There has been no method of changing or modulating the arrangement of signal points.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and particularly NTSC in satellite broadcasting.
It is an object of the present invention to provide a transmission device capable of achieving compatibility between broadcasting and HDTV broadcasting, and greatly reducing an unreceivable area within a service area for terrestrial broadcasting.

[0012]

In order to achieve the above-mentioned object, a transmission apparatus of the present invention comprises a signal input section, a carrier wave modulated by an input signal from the input section, and an m-valued signal on a signal vector diagram. A transmitter for transmitting data, which comprises a modulator for generating points and a transmitter for transmitting a modulated signal, an input unit for the above transmission signal, and a signal point of a P value on a vector diagram that can be represented by a polar coordinate system (r, θ). Modified PSK or Modified APS
It has two configurations, a demodulator for demodulating a K-modulated wave and a receiver having an output section.

[0013]

With this configuration, the first data string and the second data string having n-valued data are input as input signals, and the modulator of the transmitter transmits the modified m-valued QAM having m-valued signal points on the vector diagram. Create a modulated wave of the method. The m signal points are divided into n sets of signal points, and this signal point group is assigned to each of the n pieces of data in the first data string, and m / n in this signal point group is divided.
Each data of the second data string is assigned to the signal point or sub-signal point group, trellis-encoded, modulated, and transmitted by the transmission device. In some cases, the third data can also be transmitted.

Next, in a receiver having a demodulator with ap value of p> m, the transmission signal is received, and first, n sets of p signal points are set with respect to the p signal points on the signal space diagram. The signal of the first data string is demodulated and reproduced. Next, the p / n signal points in the corresponding signal point group are made to correspond to the second data string of the p / n value, and demodulated to reproduce the first data and the second data. At this time, the first data string and / or the second data string is trellis encoded.
In the receiver of p = n, n groups of signal points are reproduced, and n values are made to correspond to the respective groups, and only the first data string is demodulated and reproduced.

When the same signal is received from the transmitter by the above operation, the first data sequence and the second data sequence can be demodulated by the large antenna and the receiver having the multilevel demodulation capability.
At the same time, a receiver having a small antenna and a demodulation capability of a small value can receive the first data string. In this way, a compatible transmission system can be constructed. In this case, the first data string is a low frequency TV such as a low frequency component of NTSC or HDTV.
For the signal, the second data string is used for high-frequency T such as high-frequency components of HDTV.
By allocating to the V signal, an NTSC signal can be received by a receiver having a small-value demodulation capability and an HDTV signal can be received by a receiver having a multi-level demodulation capability for the same radio wave. This enables digital broadcasting compatible with NTSC and HDTV.

[0016]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In the embodiment of the present invention, a digital signal such as an HDTV signal is recorded on a recording medium such as a magnetic tape or the like, and a transmission device including a receiver for transmitting and receiving a digital signal such as a digital HDTV signal. Then, both the recording / reproducing apparatus for reproducing will be described.

However, the operation principle of the digital modulation / demodulation unit and the error correction encoder / decoder, the decoder and the encoder / decoder of the image coding of the HDTV signal, etc. according to the present invention is common to the transmission device and the recording / reproducing device. Is the same technology. Therefore, in order to efficiently explain each embodiment, the present invention will be described using a block diagram of either the transmission device or the recording / reproducing device. The configuration of each embodiment of the present invention is the same as that of QAM, ASK, PSK.
Although any method can be applied as long as it is a multi-valued digital modulation method in which signal points are arranged on a station, one modulation method will be described.

FIG. 1 shows an overall system diagram of a transmission device according to the present invention. A transmitter 1 having an input section 2, a separation circuit section 3, a modulator 4 and a transmission section 5 uses a separation circuit 3 to separate a plurality of multiplexed input signals into a first data string, D ₁ , and a second data string, D 1.
₂ and the third data string D ₃ are separated and output from the transmitter 5 as a modulated signal by the modulator 4, and the modulated signal is sent to the artificial satellite 10 through the transmission path 7 by the antenna 6.
In the artificial satellite 10, this signal is received by the antenna 11, amplified by the repeater 12, and transmitted again to the earth by the antenna 13.

The transmitted radio waves are transmitted through the transmission paths 21, 31, and 41 to the first receiver 23, the second receiver 33, and the third receiver 43.
Sent to. First, in the first receiver 23, the signal is input from the input unit 24 via the antenna 22, the demodulator 25 demodulates only the first data string, and the demodulated signal is output from the output unit 26. In this case, the second data string and the third data string have no demodulation capability.

In the second receiver 33, the signal output from the input section 34 via the antenna 32 is sent by the demodulator 35 to the first signal.
The data string and the second data string are demodulated, combined into one data string by the combiner 37, and output from the output unit 36.

In the third receiver 43, the input from the antenna 42 enters the input section 44 and the demodulator 45 inputs the first data string,
The three data strings of the second data string and the third data string are demodulated and combined into one data group by the combiner 47 and output from the output unit 46.

As described above, even when receiving the radio waves of the same frequency band from the same transmitter 1, the amount of information that can be received differs due to the difference in the performance of the demodulators of the above three receivers. Due to this feature, it is possible to simultaneously transmit three pieces of compatible information corresponding to the performance to a receiver having different performance in one radio band. For example, NTSC and HD of the same program
When transmitting three digital TV signals of a TV and a super resolution type HDTV, the super HDTV signal is separated into a low frequency component, a high frequency difference component and a super high frequency difference component, and each of them is divided into a first data string,
Corresponding to the second data string and the third data group, it is possible to simultaneously broadcast three kinds of compatible digital TV signals of medium resolution, high resolution and ultra high resolution in the frequency band of one channel.

In this case, an NTSC-TV signal can be received by a small-value demodulation receiver using a small antenna, an HDTV signal can be received by a medium-value demodulation receiver using a medium-sized antenna, and a multi-value demodulation can be performed by using a large-sized antenna. The receiver can receive ultra-high resolution HDTV. Further explaining FIG. 1, N
The digital transmitter 51 for performing TSC digital TV broadcasting inputs only the same data as the first data group from the input unit 52, modulates it with the modulator 54, and transmits the transmitter 55 and the antenna 5.
6 is sent to the satellite 10 by the transmission line 57 and is again transmitted to the earth by the transmission line 58.

In the first receiver 23, the demodulator 24 demodulates the received signal from the digital transmitter 1 into data corresponding to the first data string. Similarly, the second receiver 33 and the third receiver 43 demodulate a data group having the same contents as the first data string. In other words, the three receivers are digital general TV
It can also receive digital broadcasting such as broadcasting.

Now, each part will be described. 2 shows the transmitter 1
It is a block diagram of.

The input signal enters the input section 2 and is separated by the separation circuit 3 into three digital signals of a first data string signal, a second data string signal and a third data string signal.

For example, when a video signal is input, the low band component of the video signal is the first data string signal, the high band component of the video signal is the second data string signal, and the super high band component of the video signal is the third data string. It is conceivable to assign it to the signal. Isolated 3
The two signals are input to the modulation input unit 61 inside the modulator 4. Here, there is a signal point position modulation / change circuit 67 that modulates or changes the position of the signal point based on the external signal, and modulates or changes the position of the signal point according to the external signal.
In the modulator 4, amplitude modulation is performed on each of two orthogonal carrier waves to obtain a multilevel QAM signal. The signal from the modulation input section 61 is sent to the first AM modulator 62 and the second AM modulator 63. one of the carrier from the carrier generator 64 of cos (2πf _c t) are AM modulated by the 1AM modulator 62 is sent to the combiner 65, another carrier sent to the [pi / 2 phase shifter 66 It is 90 ° are phase-shifted, is fed to the 2AM modulator 63 in the form of sin (2πf _c t), after being amplitude-modulated in the multi-level, in the combiner 65 is combined with the first 2AM modulated wave, transmission It is output as a transmission signal by the unit 5. Since this method itself is generally practiced conventionally, detailed description of the operation is omitted.

The operation will be described using the first quadrant of the signal space diagram of the general 16-valued QAM in FIG. All signals generated by the modulator 4 are two orthogonal carrier waves.
Vector of Acos2πf _c t vectors 81 and Bsin2πf _c t 82
Can be expressed by a composite vector of the two vectors. If the tip of the composite vector from the 0 point is defined as a signal point, in the case of 16-value QAM, four-valued amplitude values of a ₁ , a ₂ , a ₃ , and a ₄ and b ₁ ,
A total of 16 signal points can be set by combining the four amplitude values of b ₂ , b ₃ and b ₄ . In the first quadrant of FIG. 3, C ₁₁ at signal point 83, C _{12 at} signal point 84, C _{22 at} signal point 85,
There are four signals at C _{21 at} signal point 86.

[0030] C ₁₁ is a composite vector of a vector 0-a ₁ and a vector _{0-b 1, C 11 =} a 1 cos2πf c t-b 1 sin2πf
to become _{c t = Acos (2πf c t} + dπ / 2).

Here, 0-a ₁ on the Cartesian coordinates of FIG.
The distance between them is A ₁ , the distance between a _{1 and} a ₂ is A ₂ , and the distance between 0 and b ₁ is B ₁ , b
_{The area} between _{1 and} b ₂ is defined as B ₂ and is shown in the figure.

As shown in the overall vector diagram of FIG. 4, there are a total of 16 signal points. Therefore, by making each point correspond to 4-bit information, 4-bit information transmission
It becomes possible in a cycle, that is, in one time slot.

FIG. 5 shows an example of general allocation when each point is expressed by the binary system. Of course, the greater the distance between the signal points, the easier the receiver is to distinguish. Therefore, in general, the signal points are arranged as far apart as possible. If the distance between specific signal points is reduced,
It becomes difficult for the receiver to distinguish between the two points, and the error rate becomes worse. Therefore, it is generally said that it is desirable to arrange them at equal intervals as shown in FIG. Therefore 16QA
In the case of M, the arrangement of signal points A1 = A2 / 2 is generally implemented.

Now, in the case of the transmitter 1 of the present invention, first, the data is divided into the first data sequence and the second data sequence, and depending on the case, the third data sequence. Then, as shown in FIG. 6, 16 signal points or signal point groups are divided into four signal point groups, and the four data of the first data string are first assigned to each signal point group. That is, if the first data string is 11, any one of the four signal points of the first signal point group 91 of the first data quadrant is transmitted, and if the first data string is 01, the second signal point group 92 of the second quadrant is transmitted. , 00, the third signal point group 93, 10 in the third quadrant
In this case, one of the four signal points in the fourth signal point group 94 in the fourth quadrant is selected according to the value of the second data string and transmitted. Next, in the case of 16 QAM, 2 bits of the second data string, 4-level data, and in the case of 64-level QAM, 4 b
The it and 16-value data are assigned to four signal points or sub-signal point groups in each of the 91, 92, 93, and 94 divided signal point groups as shown in FIG. All quadrants are subject to placement. The allocation of signal points to 91, 92, 93, 94 is preferentially determined by the 2-bit data of the first data group. Thus, 2 bits of the first data string and 2 bits of the second data string
Can be sent completely independently. Then, the first data string can be demodulated even by a 4PSK receiver if the antenna sensitivity of the receiver is a certain value or more. If the antenna has higher sensitivity, the modified 16QAM receiver of the present invention can demodulate both the first data group and the second data group.

Here, FIG. 8 shows an example of allocation of 2 bits of the first data string and 2 bits of the second data string.

In this case, the HDTV signal is divided into low-frequency components and high-frequency components, the low-frequency video signal is assigned to the first data string, and the high-frequency video signal is assigned to the second data string.
The PSK reception system can reproduce the NTSC equivalent video of the first data string, and the 16QAM or 64QAM reception system can reproduce both the first data string and the second data string, and by adding them, an HDTV video is obtained. be able to.

However, when the distances between signal points are made equal as shown in FIG. 9, there is a threshold distance from the 4PSK receiver to the shaded portion in the first quadrant. If the threshold distance is A _TO , the amplitude of A _TO is sufficient if only 4PSK is sent. However, if 16 QAM is sent while maintaining A _TO , 3 A _TO, that is, a triple amplitude is required.
That is, nine times as much energy is required as compared with the case of transmitting 4PSK. Sending 4PSK signal points in 16QAM mode without any consideration results in poor power utilization efficiency. Also, it becomes difficult to reproduce the carrier wave. The power available for satellite transmission is limited. Such a system with low power use efficiency is not practical until the satellite transmission power increases. 4PSK when digital TV broadcasting starts in the future
It is expected that a large number of receivers will be available. It cannot be said that it is impossible to increase the reception sensitivity of these once they have spread, because the compatibility problem of the receiver occurs. Therefore,
The transmission power in 4PSK mode cannot be reduced. For this reason 16
When sending a signal point of pseudo 4PSK in the QAM mode, it is expected that a method of lowering the transmission power as compared with the conventional 16QAM is required. Otherwise, it will not be possible to transmit with the limited satellite power.

The features of the present invention are shown in FIG.
The transmission power of the pseudo 4PSK type 16QAM modulation can be lowered by separating the four divided signal point groups of 94 from each other.

Here, in order to clarify the relationship between the reception sensitivity and the transmission output, returning to FIG. 1, the reception system of the digital transmitter 51 and the first receiver 23 will be described.

First, the digital transmitter 51 and the first receiver 2
Reference numeral 3 is a general transmission device for performing data transmission or video transmission including broadcasting. As shown in FIG. 7, the digital transmitter 51 is a 4PSK transmitter, which is obtained by removing the AM modulation function from the multilevel QAM transmitter 1 described in FIG. The input signal is input to the modulator 54 via the input unit 52. In the modulator 54, the modulation input unit 121 divides the input signal into two signals to phase-modulate the reference carrier wave.
-2 phase phase modulation circuit 122 and 2nd-2 phase modulation circuit 123 that modulates a carrier having a 90 ° phase difference from the reference carrier
And these phase modulated waves are combined by the combiner 65,
It is transmitted by the transmitter 55.

FIG. 18 shows a modulation signal space diagram at this time. It is common knowledge that four signal points are set and the distances between the signal points are made equal in order to improve the power use efficiency. As an example, the case where the signal point 125 is defined as (11), the signal point 126 is defined as (01), the signal point 127 is defined as (00), and the signal point 128 is defined as (10) is shown. In this case, in order for the first receiver 23 of 4PSK to receive satisfactory data, the output of the digital transmitter 51 is required to have an amplitude value above a certain level. Referring to FIG. 18, the minimum amplitude value of the transmission signal that is the minimum required for the first receiver 23 to receive the signal of the digital transmitter 51 at 4 PSK, that is, 0-a ₁
If the distance between them is defined as A _TO , the first receiver 23 can receive if the transmission is performed with the minimum amplitude A _TO which is the transmission limit.

Next, the first receiver 23 will be described. First
The receiver 23 receives the transmission signal from the transmitter 1 or the transmission signal of 4PSK from the digital transmitter 51 through the repeater 12 of the satellite 10 with the small antenna 22, and the demodulator 24 receives the reception signal as a 4PSK signal. And demodulate. The first receiver 23 is originally the 4P of the digital transmitter 51.
It is designed to receive SK or 2PSK signals and receive signals for digital TV broadcasting, data transmission, and the like.

FIG. 19 is a block diagram of the configuration of the first receiver, in which the radio wave from the satellite 12 is received by the antenna 22. This signal is input from the input section 24, and then the carrier recovery circuit 131 and the π / 2 phase shifter 132. The carrier wave and the quadrature carrier wave are reproduced by the first phase detection circuit 133 and the second phase detection circuit 1, respectively.
The quadrature components are independently detected by 34, the timing wave extracting circuit 135 identifies them separately for each time slot, and the first identification reproducing circuit 136 and the second identification reproducing circuit 137 make two independent components. The demodulated signal is demodulated into a first data string by the first data string reproducing section 232 and output by the output section 26.

Now, the received signal will be described with reference to the vector diagram of FIG. The signal received by the first receiver 23 based on the transmission wave of 4PSK of the digital transmitter 51 is 15 in FIG. 20 under ideal conditions where there is no transmission distortion or noise.
It can be represented by four signal points 1 to 154.

However, actually, the received signal points are distributed in a certain range around the signal points due to the influence of the noise in the transmission line and the amplitude distortion and the phase distortion of the transmission system. When it is separated from the signal point, it cannot be discriminated from the adjacent signal point, and the error rate gradually increases. When it exceeds a certain set range, the data cannot be restored. Even in the worst case, in order to demodulate within the set error rate, the distance between adjacent signal points should be set. This distance is defined as 2A _RO . At the time of 4PSK limit reception input, the signal point 151 is | 0-a _R1 | ≧ in FIG.
A _R0 , | 0-b _R1 | ≧ A _R0 1st discrimination area 1 shown by diagonal lines
If the transmission system is set to enter 55, the carrier wave can be demodulated if the carrier wave can be reproduced. If the minimum radius value set by the antenna 22 is r ₀ , all systems can receive the signal if the transmission output is set to a certain value or more. The amplitude of the transmission signal in FIG. 18 is set to be the minimum reception amplitude value of 4PSK of the first receiver 23, A _R0 . This minimum transmission amplitude value is defined as A _T0 . As a result, if the radius of the antenna 22 is r ₀ or more, the first receiver 23 can demodulate the signal of the digital transmitter 51 even under the worst reception conditions. When receiving the modified 16QAM and 64QAM of the present invention, it is difficult for the first receiver 23 to reproduce the carrier wave. Therefore, as shown in FIG. 25A, the transmitter 1 is (π / 4 + nπ /
By arranging 8 signal points at positions on the angle 2) and transmitting them, the carrier wave can be reproduced by the quadruple system. Also, FIG.
If 16 signal points are arranged on the extension line of the angle of nπ / 8 as shown in (b), the signal points are degenerated by adopting the carrier multiplication method of 16 multiplication method in the carrier wave reproduction circuit 131, and the pseudo 4PSK type 16QAM. The carrier wave of the modulated signal can be easily reproduced. In this case, A ₁ / (A ₁ + A ₂ ) = tan (π /
The signal point of the transmitter 1 may be set so as to be 8) and the signal may be transmitted. Consider now the case of receiving a QPSK signal. As in the signal point position modulation / change circuit 67 of the transmitter of FIG. 2, the signal point position can be superimposed on the signal point position of the QPSK signal (FIG. 18) by modulation such as AM. In this case, the signal point position demodulation unit 138 of the first receiver 23 demodulates the position modulated signal or the position change signal of the signal point into PM, AM and the like. Then, the first data string and the demodulated signal are output from the transmission signal.

Next, returning to the transmitter 1, the 16PSK transmission signal of the transmitter 1 will be described with reference to the vector diagram of FIG. 9. As shown in FIG. 9, the amplitude A of the signal point 83 in the horizontal vector direction is shown in FIG.
₁ is made larger than the 4PSK minimum transmission output A _TO of the digital transmitter 51 of FIG. Then, the signals at the signal points 83, 84, 85 and 86 in the first quadrant of FIG.
The SK receivable area 87 is entered. When these signals are received by the first receiver 23, these four signal points fall within the first discrimination area of the reception vector diagram of FIG. Therefore, the first receiver 23 judges that any of the signal points 83, 84, 85, and 86 in FIG. 9 is the signal point 151 in FIG. 20, and (11)
Data is demodulated in this time slot. As shown in FIG. 8, this data is (11) of the first divided signal point group 91 of the transmitter 1, that is, (11) of the first data string. In the case of the second quadrant, the third quadrant, and the fourth quadrant, the first data string is demodulated similarly. That is, the first receiver 23 demodulates only the 2-bit data of the first data string of the multiple data strings of the modulated signal from the transmitter 1 of 16QAM, 32QAM, or 64QAM.
In this case, since the signals of the second data string and the third data string are all included in the first to fourth divided signal point groups 91, they do not affect the demodulation of the signals of the first data string. However, since it affects the reproduction of the carrier wave, it is necessary to take measures as described later.

If there is no limit to the output of the satellite repeater, the conventional signal point equidistant type 16 to 16 shown in FIG.
It can be realized with 64QAM. However, unlike the terrestrial transmission, as described above, in satellite transmission, the launch cost increases significantly as the weight of the satellite increases. Therefore, the transmission output is restricted by the output limit of the repeater of the main body and the power limit of the solar cell. This state will continue for the time being, unless the launch cost of the rocket is reduced by technological innovation. The transmission output is 20 W for a communication satellite and about 100 W to 200 W for a broadcasting satellite. Therefore, 16QA of the signal point equidistant method as shown in FIG.
When 4PSK is transmitted by M, the amplitude of 16QAM is 2A ₁ = A ₂ , so 3A _{TO is} required, which is 9 times as much as the power. 4PSK for compatibility
9 times the power required. And when trying to make the first receiver of 4PSK possible with a small antenna, now,
It is difficult to obtain such an output with the planned satellite. For example, a 40 W system requires 360 W and cannot be economically realized.

Considering here, when all the receivers are antennas of the same size, if the transmission power is the same, the equidistant signal point system outer lot number efficiency is good. However, if we consider a system that combines receiver groups of antennas of different sizes, we can construct a new transmission method.

More specifically, 4PSK allows a simple and low-cost receiving system using a small antenna to receive signals, thereby increasing the number of receivers. Next, 16QAM is a high-performance but high-cost multi-level demodulation receiving system that uses a medium-sized antenna, and provides high-value-added services such as HDTV, which is worth the investment, by limiting the target to specific recipients. To establish. By doing so, it is possible to hierarchically transmit 4PSK, 16QAM, and in some cases 64DMA by only slightly increasing the transmission output.

For example, by setting the signal point intervals so that A1 = A2 as shown in FIG. 10, the total transmission output can be reduced. Amplitude A (4) for transmitting this case 4PSK can be expressed by a vector 95, the 2A ₁ ² of the square root. The overall amplitude A (16) can be represented by the vector 96 (A
_{It is} the square root of ₁ + A ₂ ) ² + (B ₁ + B ₂ ) ² .

| A (4) | ² = A ₁ ² + B ₁ ² = A _TO ² + A _TO ² = 2A _TO ² | A (16) | ² = (A ₁ + A ₂ ) ² + (B ₁ + B ₂ ) ² = 4A
_TO ² + 4A _TO ² = 28A _{T O} ² | A (16) | / | A (4) | = 2 That is, transmission can be performed with twice the amplitude and four times the transmission energy when transmitting 4PSK. A general receiver that transmits at equidistant signal points cannot demodulate modified 16-value QAM, but by setting two thresholds A ₁ and A ₂ in advance,
It can be received by the receiver 33. In the case of FIG. 10, the shortest distance of the signal points in the first divided signal point group 91 is A ₁ and is 4PS.
Compared to signal point distance 2A ₁ of K A ₂ / 2A ₁ becomes. A ₁
Since the distance between signal points is 1/2 than = A ₂ , it is necessary to have a reception sensitivity of twice the amplitude and a reception sensitivity of four times for energy in order to obtain the same error rate. To obtain 4 times the receiver sensitivity, if the radius r ₂ of the antenna 32 of the second receiver 33 twice i.e. r ₂ = 2r ₁ as compared to the radius radius r ₁ of the antenna 22 of the first receiver 23 Good. For example, if the antenna of the first receiver 23 has a diameter of 30 cm, it can be realized by setting the antenna diameter of the second receiver 33 to 60 cm. Thus, by demodulating the second data string and assigning it to the high frequency component of HDTV, a new service such as HDTV can be performed on the same channel. Since the service content is doubled, the receiver can receive the service corresponding to the investment of the antenna and the receiver. Therefore, the second receiver 33 may have a higher cost accordingly. Here, since the minimum transmission power is determined for the 4PSK mode reception, A in FIG.
Modification 1 for 4PSK transmission power by ratio of ₁ and A ₂
The transmission power ratio n _{16 of} 6APSK and the antenna radius r ₂ of the second receiver 33 are determined.

Calculation to measure this optimization shows that 4
The minimum required transmission energy of PSK is {(A ₁ + A ₂ ) /
A ₁ } ² times If this is defined as n ₁₆ , the distance between signal points when receiving with modified 16-value QAM is A ₂ , the distance between signal points when receiving with 4PSK is 2A ₁ , and the ratio of the distance between signal points Is A ₂ / 2A, and the radius of the receiving antenna is r ₂ , the relationship shown in FIG. 11 is obtained. The curve 101 indicates the transmission energy ratio n ₁₆ and the radius r of the antenna 22 of the second receiver 23.
Represents the relationship of ₂ .

Point 102 is 16QA in the case of equidistant signal points
In the case of transmitting M, as described above, it requires 9 times as much transmission energy, which is not practical. From FIG. 11, it can be seen from the graph that the antenna radius r ₂ of the second receiver 23 does not become so small even if n ₁₆ is increased five times or more.

In the case of satellites, the transmission power is limited,
It cannot be above a certain value. From this, it becomes clear that n16 is preferably 5 times or less. This area is indicated by the hatched area 103 in FIG. For example, in this area, for example, the point 104 has four times the transmission energy and the antenna radius r ₂ of the second receiver 23 has twice. Further, at point 105, the transmission energy is doubled, and r ₂ is approximately 5 times. These are in a practically applicable range.

Expressing that n ₁₆ is smaller than 5 by A ₁ and A ₂ , n ₁₆ = ((A ₁ + A ₂ ) / A ₁ ) ² ≤5 A ₂ ≤1.23A _{1 From} FIG. If the distance between them is 2A (4) and the maximum amplitude is 2A (16), A (4) and A (16) -A (4) are A ₁ and A ₂
Therefore, {A (16)} ² ≤5 {A (14)} ² may be set. Next, an example using a modified 64APSK modulation will be shown. The third receiver 43 can perform 64-value QAM demodulation.

The vector diagram of FIG. 12 shows the case where the divided signal point group of the vector diagram of FIG. 10 is increased from 4 values to 16 values. In the first divided signal point group 91 of FIG.
Signal points of 4 × 4 = 16 values starting from 0 are arranged at equal intervals. In this case, in order to have compatibility with 4PSK, the transmission amplitude must be set to A ₁ ≧ A _TO .
Transmission is performed with the radius of the antenna of the third receiver 43 as r ₃ .
The value of r ₃ when defined as output signal n64, when determined in the same manner ^{_{r 3 2 = {6 2 /}} (n-1)} r 1 2 , and the radius r ₃ in FIG. 13 64 value QAM - Output multiple It becomes a graph like n.

However, in the arrangement as shown in FIG. 12, since only 2 bits of 4PSK can be demodulated when received by the second receiver 33, in order to establish the compatibility of the first, second and third, the second reception It is desirable that the machine 33 has a function of demodulating modified 16-value QAM from a modified 64-value QAM modulated wave.

Compatibility of three receivers is established by performing grouping of signal points in three layers as shown in FIG. Explaining only in the first quadrant, it has been described that the first divided signal point group 91 is assigned the 2-bit (11) of the first data string.

Next, the second sub-divided signal point group 181 has a second
Allocate 2-bit (11) in the data string. (01) is assigned to the second sub-divided signal point group 182, (00) is assigned to the third sub-divided signal point group 183, and (10) is assigned to the fourth sub-divided signal point group 184. This is equivalent to FIG.

The signal point arrangement of the third data string will be described in detail with reference to the vector diagram of the first quadrant in FIG. 15. For example, signal points 201, 205, 209 and 213 are (11), signal points 202, 206, 210, 214 to (01), signal point 2
03, 207, 211, and 215 (00), signal point 20
If 4,208,212,216 are (10), the third
The 2-bit data of the data string can be transmitted independently of the first data and the second data, and the 3-bit 2-bit data can be transmitted independently.

Not only is 6-bit data sent, but a receiver with three levels of different performance is a feature of the present invention.
Data having different transmission amounts of 4 bits, 4 bits, and 6 bits can be transmitted, and compatibility between transmissions of three layers can be provided.

Here, a method of arranging the signal points required to have compatibility at the time of three-layer transmission will be described.

As shown in FIG. 15, first, in order for the first receiver 23 to receive the data of the first data string, A ₁
It has already been stated that ≧ A _TO .

Next, the signal point of the second data string, for example, FIG.
Signal point 91 and the sub-divided signal point groups 182, 18 in FIG.
It is necessary to secure the distance between signal points so that the signal points of 3,184 can be distinguished.

FIG. 15 shows the case where the distance is 2 / 3A ₂ . In this case the signal between point distance of the internal signal points 201 and 202 of the first sub-division signal point group 181 becomes A _2/6. Third
The reception energy required for reception by the receiver 43 is calculated. In this case, the radius of the antenna 32 is r ₃ ,
The required transmission energy is 4 PSK transmission energy n ₆₄
When defined as double, r ₃ ² = (12r ₁ ) ² / (n−1). This graph can be represented by the curve 221 in FIG. For example, point 2
In the case of 22 and 223, if the transmission energy of 6 times the 4PSK transmission energy is obtained, the antenna of 8 times radius is used, and if the transmission energy of 9 times is used, the antenna of 6 times is used for the first, second and third data strings. You can see that you can demodulate. In this case, since the distance between the signal points of the second data string approaches 2 / 3A ₂ , r ₂ ² = (3r ₁ ) ² / (n−1), and the antenna 32 of the second receiver 33 slightly changes as shown by the curve 223. Needs to be increased.

This method sends the first data sequence and the second data sequence while the satellite transmission energy is small as at the present time, and in the future when the satellite transmission energy is greatly increased, the first receiver 23 and the second data sequence are transmitted. A large effect in terms of both compatibility and developability that the third data string can be sent without damaging the reception data of the second receiver 33 and without modification is obtained.

In order to explain the reception state, the second receiver 33 will be described first. The above-mentioned first receiver 23 originally has a radius r
It is set to demodulate the 4PSK modulated signal of the digital transmitter 51 and the first data string of the transmitter _{1 with} a small antenna of 1, while the second receiver 33 is shown in FIG. 16-value signal point, that is, 1 in the second data string
A 2-bit signal of 6QAM can be completely demodulated. A 4-bit signal can be demodulated together with the first data string. In this case, the ratio of A1 and A2 differs depending on the transmitter. This data is set by the demodulation control unit 231 in FIG. 21, and the threshold value is sent to the demodulation circuit. This enables AM demodulation.

A block diagram of the second receiver 33 of FIG. 21,
The block diagram of the first receiver 23 in FIG. 19 has almost the same configuration. The difference is that the antenna 32 has a larger radius r ₂ than the antenna 22. Therefore, it is possible to discriminate a signal having a shorter distance between signal points. Next, demodulator 3
5, a demodulation control unit 231 and a first data string reproduction unit 2
32 and a second data string reproducing unit 233. The first identification reproduction circuit 136 has an AM demodulation function for demodulating the modified 16QAM. In this case, each carrier has a quaternary value and has a zero level and ± 2 binary threshold values. In the case of the present invention,
Because of the modified 16QAM signal, the threshold differs depending on the transmission output of the transmitter as shown in the signal vector diagram of FIG. Therefore,
Assuming that TH ₁₆ is a standardized threshold value, FIG.
As apparent from the _{TH 16 = (A 1 + A} 2/2) / (A 1 + A 2).

The A1, A2 or TH ₁₆ and the demodulation information of the multilevel modulation value m are transmitted from the transmitter 1 while being included in the first data string. Further, the demodulation control unit 231 can obtain a demodulation information by statistically processing the received signal.

The shift factors A ₁ / A ₂ will be described with reference to FIG.
A method of determining the ratio of will be described. The threshold value changes when A ₁ / A ₂ is changed. Error accordance A ₁ / A ₂ set at the receiver side moves away from the value of A ₁ / A ₂ set at the transmitter side will increase. The demodulated signal from the second data string reproducing unit 233 of FIG. 26 is fielded back to the demodulation control circuit 231 to control the shift factors A ₁ / A ₂ in the direction of decreasing the error rate, whereby the third receiver 43 shifts the shift factor. A
_The circuit becomes simple because it is not necessary to demodulate ₁ / A ₂ . Further, the transmitter does not need to send A ₁ / A _2, which has the effect of increasing the transmission capacity. This can also be used for the second receiver 33. The demodulation control circuit 231 is a memory 231a
have. When a threshold different for each channel of TV broadcasting, that is, a shift ratio, the number of signal points, and a synchronization rule are stored and the channel is received again, there is an effect that reception is fast and stable by calling this value.

When this demodulation information is unknown, it becomes difficult to demodulate the second data string. Hereinafter, description will be given using the flowchart of FIG.

Even if demodulation information cannot be obtained, step 3
It is possible to demodulate 4PSK of 13 and the first data string of step 301. Therefore, in step 302, the demodulation information obtained by the first data string reproducing unit 232 is converted to the demodulation control unit 23.
Send to 1. The demodulation control unit 231 determines that m is 4 in step 303.
Or if it is 2, 4PSK or 2PSK in step 313
Demodulate. If NO, in step 304, m is 8 or 1.
If 6, go to step 305. If NO, step 3
Go to 10. At step 305, TH8 and TH16 are calculated. In step 306, the demodulation controller 231 sends the AM demodulation threshold TH16 to the first identification reproduction circuit 136 and the second identification reproduction circuit 137, and in steps 307 and 315, the modified 16QAM demodulation and the reproduction of the second data string are performed. The error rate is checked in step 308. If the error rate is bad, the process returns to step 313 to perform 4PSK demodulation.

Further, in this case, the signal point 85.83 in FIG.
Is on the angle cos (ωt + nπ / 2), but signal point 84.86 is not on this angle. Therefore, the second data string reproducing unit 233 of FIG. 21 sets carrier wave sending information of the second data string to the carrier wave reproducing circuit 131 so that the carrier wave is not extracted from the signal at the timing of the signal point 84.86.

Assuming that the second data string cannot be demodulated, the transmitter 1 intermittently sends the carrier timing signal by the first data string. Even if the second data string cannot be demodulated by this signal, the signal points 83.
I understand 85. Therefore, the carrier wave can be reproduced by transmitting the carrier wave transmission information to the carrier wave reproduction circuit 131.

Next, when the modified 64QAM signal as shown in FIG. 23 is sent from the transmitter 1, returning to the flowchart of FIG. 24, it is judged at step 304 whether m is 16 or not. At step 310, m is 64. The following is checked, and if it is not the equidistant signal point method in step 311, the process proceeds to step 312. Here is the TH ₆₄ = the seek distance TH ₆₄ between signal points upon deformation _{64QAM (A 1 + A 2/} 2) / (A 1 + A 2), the same as the TH _16. However, the distance between signal points becomes smaller.

If the distance between the signal points in the first sub-divided signal point group 181 is A ₃ , the first sub-divided signal point group 181
And the distance between the second sub-divided signal point group 182 is (A ₂ -2A ₃ ),
When scaling the _{(A 2 -2A 3) / (} A 1 + A 2). When this is defined as d ₆₄ , if d ₆₄ is equal to or less than the discrimination ability T ₂ of the second receiver 33, discrimination cannot be performed. In this case, the determination is made in step 313, and if d ₆₄ is outside the allowable range, the 4PSK mode in step 313 is entered. If it is within the discrimination range, proceed to step 305, and 16QAM of step 307.
Demodulate. If the error rate is high in step 308, the 4PSK mode of step 313 is entered.

In this case, if the transmitter 1 transmits the modified 8QAM signal of the signal points as shown in FIG. 25A, all the signal points are on the angle of cos (2πf + n · π / 4). The quadrupling circuit has the effect of facilitating the reproduction of carrier waves because all carrier waves are degenerated into the same phase. In this case, the 2 bits of the first data string can be demodulated by the 4PSK receiver without consideration, and the second receiver 33
2b of the second data string is shown in FIG. 25 (a) and FIG. 25 (b).
The signal point arrangement diagram of shows the signal point of C-CDM when the signal point shifted in the polar coordinate direction (r, θ) is added. The C-CDM in which the signal points are shifted on the Cartesian coordinates, that is, the XY directions, is referred to as a Cartesian coordinate system C-CDM, and the polar coordinate system, that is, the C-CDM in which the signal points are shifted in the r and θ directions.
Is called the polar coordinate system C-CDM.

First, the signal point constellation diagram of 8PS-APSK in FIG. 25A is obtained by adding another signal point shifted in the radius r direction in polar coordinates to each of the four signal points of QPSK. Thus, as shown in FIG. 25 (a), polar coordinate C-CDM with 8 signal points from QPSK
APSK will be realized. This is the polar (P
ole) is an APSK to which a signal point obtained by shifting is added, and is therefore referred to as SP-APSK for Shifted Pole-APSK. In this case, the coordinates of the signal point 85 added to QPSK can be defined by using the shift factor S ₁ as shown in FIG. The signal point of 8PS-APSK is a signal point ((S of the standard QPSK polar coordinates (r ₀ , θ ₀ ) which is shifted by S ₁ r _{0 in the} radius r direction ((S
₁ +1) r ₀ , θ ₀ ) is added. Thus Q
1-bit sub-channel 2 is added to 2-bit sub-channel 1 which is the same as PSK.

Further, as shown in the constellation diagram of FIG. 140, the coordinates (r ₀ , θ ₀ ), (r ₀ + S ₁ r ₀ , θ ₀ ).
By adding signal points shifted by S2ro in the radius r direction to the 8 signal points of (r ₀ + S ₂ r ₀ ,
A 1-bit signal point of (θ ₀ ) and (r ₀ + S ₁ r ₀ + S ₂ r ₀ , θ ₀ ) is added. This is 1b because there are two types of arrangement.
The sub-channel of it is obtained. This is 16PS-A
Called PSK, 2 bit subchannel 1 and 1 bit
And sub-channel 3 of 1 bit. Also for 16-PS-APSK, θ = 1/4 (2n + 1) π
Since there is a signal point above, the normal QPSK explained in FIG.
Since the carrier wave can be reproduced by the receiver, the second sub-channel cannot be demodulated, but the 2-bit first sub-channel can be demodulated. In this way, the C-CDM system which shifts in the polar coordinate direction is the mainstream in PSK, especially in the present satellite broadcasting.
There is an effect that the amount of transmission information can be expanded while maintaining compatibility with the PSK receiver. Therefore, the second-generation APS without losing the viewers of the first-generation satellite broadcasting using PSK.
It can be extended to satellite broadcasting with a large amount of information of multi-level modulation using K while maintaining compatibility.

The signal point in the case of FIG. 25B is above the angle = π / 8 in polar coordinates. This is limited to the signal points of each quadrant, that is, 12 signal points out of the signal points of each 16 quadrant of 4 quadrants, that is, 16 signal points in total. By limiting, when viewed roughly, these three signal points can be regarded as one signal point, and can be regarded as four QPSK signal points in total. In this way, QPSK
The receiver can be used to reproduce the first sub-channel.

These signal points are θ = π / 4, θ = π / 4
They are arranged on the angles of + π / 8 and θ = π / 4-π / 8.
That is, a signal point obtained by shifting a QPSK signal point on the angle π / 4 by ± π / 8 in the angular direction of polar coordinates is added. Since it is in the range of θ = π / 4 ± π / 8, it can be regarded as one signal point on θ = π / 4 of about θPSK. Although the error rate in this case is slightly worse, Q shown in FIG.
The PSK receiver 23 can discriminate from the signal points on four angles and thus can be demodulated to reproduce 2-bit data.

In the case of the angle shift C-CDM, the angle is π /
If n, the carrier wave regenerating circuit can regenerate the carrier wave by the n multiplying circuit as in the other embodiments. Also π / n
If not, the carrier can be regenerated by sending several pieces of carrier information in a fixed period as in the other embodiments.

Further, as shown in FIG. 141, when the angle in polar coordinates between the signal points of QPSK or 8-SP-APSK is 2θ ₀ and the primary angle shift factor is P ₁ , the signal points are divided into two and the angle is divided. By shifting by ± P ₁ θ _{0 in the} θ direction, the signal is divided into two signal points in the case of QPSK (r ₀ , θ ₀ + P ₁ θ ₀ ) and (r ₀ , θ ₀ −P ₁ θ ₀ ). The number of points doubles. Thus 1-bit subchannel-
3 is added. This is called 8-SP-PSK with P = P ₁ . As shown in FIG. 142, a signal point obtained by shifting the signal point of 8-SP-PSK by S ₁ r ₀ in the radius r direction is called 16-SP-APSK (P, S ₁ type). Subchannel 1.2 can be reproduced by 8PS-PSK having the same phase. Now, return to FIG. 25 (b) here. The C-CDM using the angle shift of the polar coordinate system is shown in FIG.
Since it can be applied to PSK like No. 41, it can also be used for first generation satellite broadcasting. However, the second generation AP
When used for SK satellite broadcasting, as shown in FIG. 142, the polar coordinate system C-CDM cannot evenly space the signal points in the group. Therefore, the power use efficiency is poor. On the other hand, C-CDM in Cartesian coordinates has poor compatibility with PSK.

The system of FIG. 25 (b) is compatible with both the rectangular coordinate system and the polar coordinate system. Since the signal points are arranged on the angle of 16PSK, demodulation can be performed by 16PSK, and since the signal points are grouped, the QPSK receiver can also demodulate. Since it is also arranged on Cartesian coordinates, it can be demodulated even by 16-SRQAM. QPSK, 16P
This is a system that has a great effect that it can be expanded while realizing compatibility between the polar coordinate system and the Cartesian coordinate system C-CDM among the three SK and 16-SRQAM. It can be played, and a total of 3 bits can be played.

Next, the third receiver 43 will be described. Figure 2
6 is a block diagram of the third receiver 43, which has substantially the same configuration as the second receiver 33 of FIG. The difference is that the third data string reproducing unit 234 is added and that the discrimination reproducing circuit has the 8-level discrimination ability. Radius r _{3 of} antenna 42
Is larger than r _2, it is possible to demodulate a signal having a closer distance between signal points, for example, 32-value QAM or 64-value QAM. Therefore, in order to demodulate 64-value QAM, the first identification / reproduction circuit 136 needs to discriminate the 8-value level from the detection signal wave. In this case, there are seven threshold levels. Since one of them is 0, there are three thresholds in one quadrant.

As shown in the signal space diagram of FIG. 27, there are three thresholds in the first quadrant.

As shown in FIG. 27, there are three normalized thresholds, TH1 ₆₄ , TH2 ₆₄ and TH3 ₆₄ .

[0088] _{TH1 64 = (A 1 + A} 3/2) / (A 1 + A 2) TH2 64 = (A 1 + A 2/2) / (A 1 + A 2) TH3 64 = (A 1 + A 2 -A 3 / 2) / (A ₁ + A ₂ )

By the AM demodulation of the phase-detected reception signal with this threshold value, the data of the third data string is demodulated in the same manner as the first data string and the second data string described in FIG. As shown in FIG. 23, the third data string is, for example, the first data string.
Four signal points 201, 20 in the sub-divided signal group 181
By distinguishing 2, 203, 204, 4 values, that is, 2 bits
Can be taken. In this way, it becomes possible to demodulate 6 bits, that is, modified 64-value QAM.

At this time, the demodulation control unit 231 knows the values of m, A ₁ , A ₂ , and A _{3 from} the demodulation information included in the first data string of the first data string reproducing unit 232, and therefore the threshold value TH is set.
1 ₆₄ , TH2 _64, and TH3 ₆₄ are calculated and sent to the first identification reproduction circuit 136 and the second identification reproduction circuit 137, and modified 64QA
M demodulation can be performed reliably. In this case, since the demodulation information is scrambled, it is possible to allow only authorized receivers to demodulate 64QAM.
FIG. 28 shows a flowchart of the demodulation control unit 231 of modified 64QAM. Only the points different from the 16-value QAM flowchart in FIG. 24 will be described. Step 304 of FIG. 28
From step 320, if m = 32, step 322
32 value QAM is demodulated. If NO, m in step 321
= 64, and since A ₃ cannot be reproduced from the set value or less in step 323, the flow proceeds to step 305 and the same flowchart as in FIG. 24 is executed, and the modified 16QAM demodulation is performed. Here, returning to step 323, if A ₃ is greater than or equal to the set value, the threshold value is calculated in step 324, and step 3
In step 25, three thresholds are sent to the first and second identification / reproduction circuits to reproduce modified 64QAM, and in step 3
At 27, the first, second, and third data are reproduced. At step 328, if the error rate is large, 16QAM demodulation is suitable for step 305, and if it is small, 64QAM demodulation is continued.

Here, a carrier recovery system important for demodulation will be described. The present invention is modified 16QAM and modified 64QA
One of the features is that the first data string of M is reproduced by the 4PSK receiver. In this case, when a normal 4PSK receiver is used, it is difficult to reproduce the carrier wave and normal demodulation cannot be performed. To prevent this, some countermeasures are required on the transmitter side and the receiver side.

There are two types of methods according to the present invention. The first method is intermittent (2n-1) with a fixed rule base.
This is a method of transmitting signal points on an angle of π / 4. The second method is a method in which substantially all signal points are arranged and transmitted on an angle of nπ / 8.

The first method is, as shown in FIG. 38, signal points on four angles, π / 4, 3π / 4, 5π / 4, and 7π / 4, for example, signals at signal points 83 and 85. 38, the synchronous time slots 452, 453, 454, 455, which are intermittently sent, are set in the time slot group 451 in the time chart of the transmission signal of FIG. 38 based on a certain rule. To do. Then, during this period, one signal point among the eight signal points on the angle is surely transmitted. Arbitrary signal points are transmitted in the other time slots. Then, the transmitter 1 arranges the above rule for transmitting this time slot in the synchronization timing information section 499 of the data shown in FIG. 41 and transmits it.

The contents of the transmission signal in this case will be described in more detail with reference to FIG. 41.
Time slot group 451 including 453, 454, 455
Constitutes one unit data string 491, Dn.

Since synchronization time slots are intermittently arranged in this signal based on the rule of the synchronization timing information, if this allocation rule is known, the carrier recovery can be easily performed by extracting the information in the synchronization time slot. it can.

On the other hand, at the beginning of the frame of the data string 492, there is a sync area 493 indicated by S, which is composed of only sync time slots indicated by diagonal lines. With this configuration, the amount of extracted information for reproducing the carrier wave increases, so that 4P
There is an effect that the carrier wave reproduction of the SK receiver can be surely and quickly performed.

This synchronization area 493 includes S1, S2 and S3.
The synchronization parts 496, 497, 498, etc. shown by are included in this part, which contains the unique word for synchronization and the demodulation information described above. There is also a phase synchronization signal arrangement information section 499 indicated by I _T , which contains information such as arrangement intervals of phase synchronization time slots and arrangement rule information.

Since the signal point in the area of the phase synchronization time slot has only a specific phase, the carrier wave can be reproduced by the 4PSK receiver. Therefore, the content of the phase synchronization section arrangement information I _T can be surely reproduced. Can reliably reproduce the carrier wave.

Next to the synchronization area 493 in FIG. 41, there is a demodulation information section 501, which contains demodulation information relating to the threshold voltage required when demodulating a modified multilevel QAM signal.
Since this information is important for demodulation of multilevel QAM, if the demodulation information 502 is put in the synchronization area like the synchronization area 502 in FIG. 41, the demodulation information can be obtained more reliably.

FIG. 42 is a signal arrangement diagram when a burst signal is transmitted by the TDMA method. The difference from FIG. 41 is that a guard time 521 is provided between the data string 492, Dn and another data string, and no transmission signal is transmitted during this period. A synchronization unit 522 is provided at the beginning of the data string 492 for synchronization. During this period, only the signal point having the above-mentioned (2n-1) π / 4 phase is transmitted. Therefore, the carrier can be regenerated by the 4PSK demodulator.
In this way, synchronization and carrier wave reproduction are possible even in the TDMA system.

Next, the carrier recovery system of the first receiver 23 of FIG. 19 will be described in detail with reference to FIGS. 43 and 44. The received signal input in FIG. 43 enters the input circuit 24,
One of the demodulated signals synchronously detected by the synchronous detection circuit 541 is sent to and output from the output circuit 542, and the first data string is reproduced. The extraction timing control circuit 543 reproduces the phase synchronization part arrangement information part 499 of FIG. 41 to know at what timing the signal of the (2n−1) π / 4 phase synchronization part comes in, and the intermittent as shown in FIG. Phase synchronization control signal 56
1 is sent. The demodulated signal is sent to the multiplication circuit 545 and 4
It is multiplied and sent to the carrier wave reproduction control circuit 54. Figure 44
Signal 562 of true phase information 563 and other signals. As indicated by the diagonal lines in the timing chart 564, the phase synchronization time slot 452 including the signal points having the phase of (2n-1) π / 4 is intermittently included. This is sampled by the carrier wave reproduction control circuit 544 using the phase synchronization control signal 564. Thus, the phase sample signal 565 is obtained. A predetermined phase signal 566 is obtained by sampling and holding this. This signal passes through the loop filter 546 and VCO5.
The carrier wave is sent to 47 and reproduced, and sent to the synchronous detection circuit 541. In this way, signal points having a phase of (2n-1) π / 4 as shown by the diagonal lines in FIG. 39 are extracted. Based on this signal, an accurate carrier wave can be reproduced by the quadruple multiplication method. At this time, a plurality of phases are reproduced, but the absolute phase of the carrier wave can be specified by inserting a unique word in the synchronization unit 496 of FIG.

When the modified 64QAM signal is transmitted as shown in FIG. 40, the phase synchronization time slot 452 is provided only for the signal points in the phase synchronization area 471 indicated by the slanted line of the phase of approximately (2n-1) π / 4. The transmitter sends 452b or the like. For this reason, the carrier wave cannot be regenerated by the normal 4PSK receiver, but the 4PSK first receiver 23 also has the effect of regenerating the carrier wave by providing the carrier wave regenerating circuit of the present invention.

The above is the case where the Costas type carrier recovery circuit is used. Next, the case where the present invention is applied to the inverse modulation carrier recovery circuit will be described.

FIG. 45 shows an inverse modulation carrier recovery circuit of the present invention. The received signal from the input circuit 24 is reproduced by the synchronous detection circuit 541 as a demodulated signal. On the other hand, the input signal delayed by the first delay circuit 591 is the 4-phase modulator 5
At 92, the demodulated signal is inversely demodulated into a carrier signal. The carrier signal that has passed through the carrier reproduction control circuit 544 is sent to the phase comparator 593. On the other hand VCO
The reproduced carrier wave from 547 is output by the second delay circuit 594.
After being delayed, the phase comparator 593 compares the phase with the above-mentioned inversely modulated carrier signal, and the phase difference signal is supplied to the VCO 547 through the loop filter 546 to reproduce the carrier wave having the same phase as the received carrier wave. In this case, the extraction timing control circuit 5 is used in the same manner as the Costas carrier recovery circuit of FIG.
43 samples the phase information of only the signal points in the shaded area of FIG. 39, so 16QAM or 64QAM
However, the carrier wave can be reproduced by the 4PSK modulator of the first receiver 23.

Next, a method of reproducing a carrier wave by the 16-multiplication method will be described. As shown in FIG. 46, the transmitter 1 of FIG. 2 arranges the signal points of modified 16QAM in the phase of nπ / 8 and performs modulation and transmission. First receiver 2 of FIG.
In the case of No. 3, by using a Costas type carrier recovery circuit having a 16 multiplication circuit 661 as shown in FIG.
The carrier wave can be reproduced. With the 16-multiplier circuit 661, FIG.
Since the signal point having a phase of nπ / 8 such as 6 is degenerated to the first quadrant, the carrier can be regenerated by the loop filter 546 and the VCO 541. It is also possible to extract the absolute phase from the 16 phases by arranging the unique word in the synchronization area.

Next, the structure of the 16-multiplication circuit will be described. From the demodulated signal, the sum signal 662 and the difference circuit 663 give the sum signal,
Create a difference signal and multiply by the multiplier 664 to obtain cos2θ
To make. The multiplier 665 produces sin2θ.
These are multiplied by the multiplier 666 to create sin4θ.

Similarly, from sin2θ and cos2θ, the sum circuit 667, the difference circuit 668 and the multiplier 670 are used to obtain s.
Make in8θ. The sum circuit 671, the difference circuit 672, and the multiplier form con8θ. Then, by multiplying sin16θ by the multiplier 674, multiplication by 16 is possible.

According to the 16-multiplication method as described above, FIG.
There is a great effect that the carrier waves of all the signal points of the modified 16QAM signal having the above signal point arrangement can be reproduced without extracting a specific signal point.

The modified 64Q having the arrangement shown in FIG.
Although the carrier wave of the AM signal can also be reproduced, some signal points are slightly deviated from the synchronization area 471, so that the error rate during demodulation increases.

There are two methods for dealing with this. One is not transmitting a signal at a signal point out of the synchronization area, which reduces the amount of information, but has the effect of simplifying the configuration.
The other is to provide a synchronization time slot as described in FIG. During the period of the synchronous time slot in the time slot group 451, by sending the signal points of the synchronous phase regions 471, 471a and the like having the phase of nπ / 8 indicated by diagonal lines, accurate synchronization can be achieved during this period. Therefore, the phase error is reduced.

As described above, by the 16-multiplying method, a simple receiver configuration is modified by the 4PSK receiver to obtain 16QA.
There is a great effect that the carrier of the M or modified 64QAM signal can be reproduced. Further, when the synchronization time slot is further set, it is possible to obtain the effect of increasing the phase accuracy when reproducing the carrier wave of the modified 64QAM.

As described in detail above, by using the transmission device of the present invention, it is possible to simultaneously transmit a plurality of data in one radio band in a hierarchical structure.

In this case, it is possible to demodulate a data amount commensurate with the investment of the receiver by setting receivers of three layers having different receiving sensitivities and demodulation capabilities for one transmitter. First, a person who purchased a first receiver with a small antenna and low resolution but low cost can demodulate and reproduce the first data string. Next, a receiver who purchased a medium-sized antenna and a high-cost second receiver with medium resolution can reproduce the first and second data strings. Further, a person who purchased a large-scale antenna and a high-resolution, fairly high-cost third receiver can demodulate and reproduce all the first, second, and third data strings.

If the first receiver is a home digital satellite broadcasting receiver, the receiver can be realized at a low price that can be accepted by many general consumers. The second receiver is initially unacceptable to the general consumer because it requires a large antenna and is costly, but it is worthwhile for people who want to watch HDTV to be a little expensive. The third receiver requires a fairly large industrial antenna until the satellite output increases and is not practical for home use and is initially suitable for industrial use. For example, if an ultra-high resolution HDTV signal is sent and transmitted to a movie theater in various places by satellite, the movie theater can be digitized by video. In this case, the operating costs of movie theaters and video theaters will also be reduced.

As described above, when the present invention is applied to TV transmission, there is a great effect that video services of three image qualities can be provided in one frequency band of radio waves and both can be compatible with each other. In the embodiment, examples of 4PSK, modified 8QAM, modified 16QAM, and modified 64QAM are shown, but 32QA
It can be realized with M or 256QAM. Further, it can also be applied to a four-valued or eight-valued ASK signal as shown in FIGS. 58 and 68 (a) and (b). Also, 8PSK, 16PS
It can be carried out with K or 32PSK. Further, although the example of satellite transmission is shown in the embodiment, it goes without saying that the same can be realized by terrestrial transmission or wired transmission.

(Embodiment 2) In Embodiment 2, the physical hierarchical structure described in Embodiment 1 is logically further divided by differentiation of error correction capability and the like, and a logical hierarchical structure is added. In the case of the first embodiment, the respective hierarchical channels have different electric signal levels, that is, physical demodulation capabilities. On the other hand, in the second embodiment, the logical reproduction ability such as the error correction ability is different. Specifically, for example, the data in the hierarchical channel of D ₁ is divided into two, for example, D _1-1 and D _1-2 , and the error correction capability of one of the divided data, for example, D _1-1 data is D
_Since the error correction capability of _D1-1 and _D1-2 data is different at the time of demodulation and reproduction, the C / N value of the transmission signal is lowered by increasing the error correction capability differently from _1-2 data. If it goes down, even if the signal level that D _1-2 cannot reproduce is D
_1-1 can reproduce the original signal within the set error rate. This can be called a logical hierarchical structure.

That is, by dividing the data of the modulation hierarchical channel and differentiating the size of the inter-code distance for error correction such as the use of the error correction code and the product code, a logical hierarchical structure based on the error correction capability is obtained. It is added to enable more detailed hierarchical transmission.

Using this, the D ₁ channel is D _1-1 ,
The two sub-channels D _1-2 and D ₂ are increased to the two sub-channels D _2-1 and D _2-2 .

This will be described with reference to FIG. 87 of C / N value of input signal and hierarchical channel number.
_1-1 can be played with the lowest input signal. This CN value is d
Then, when CN = d, D _1-1 is reproduced, but D _1-2 ,
D _2-1 and D _2-2 are not reproduced. Next, when CN = C or more, D _1-2 is further reproduced, D _2-1 is added when CN = b, and D _2-2 is added when CN = a. Thus, as CN increases, the total number of reproducible layers increases. Conversely, as CN decreases, the total number of playable layers decreases. This is the transmission distance and reproducible CN in Fig. 86.
The value diagram will be described. Generally, as the transmission distance becomes longer as shown by a solid line 861 in FIG. 86, the C / N value of the received signal decreases. The distance from the transmitting antenna at the point where CN = a described in FIG. 85 is La, and when CN = b, Lb, C
Lc for N = C, Ld for CN = d, Le for CN = e
Suppose Sakoi area than the distance from the transmitting antenna Ld only D _1-1 channel, as described in FIG. 85 can be reproduced. This D _1-1 receivable range is the shaded area 86
2 shows. As is clear from the figure, the _D1-1 channel can be reproduced in the widest area. Similarly, the D _1-2 channel can be reproduced in the area 863 within the distance Lc from the transmitting antenna. In the range within the distance Lc, since the area 862 is also included, the D1-1 channel can be reproduced. Similarly, area 86
4 can play D _2-1 channel, and area 865 is D
_2-2 channels can be played. In this way, C
Hierarchical transmission can be performed in which the number of transmission channels is gradually reduced without deterioration of the N value. By separating the data structure into a hierarchical structure and using the multilevel transmission of the present invention, it is possible to achieve a hierarchical transmission in which the data amount gradually decreases as the C / N deteriorates like analog transmission. is there.

Next, a specific structure will be described. Here, an embodiment of the physical layer 2 layer and the logical layer 2 layer will be described. FIG. 87 is a block diagram of the transmitter 1. Basically, the detailed description is omitted because it is the same as the block diagram of the transmitter of FIG. 2 described in the first embodiment, but the difference is that an error correction code encoder is added. This is abbreviated as an ECC encoder. The separation circuit 3 has four outputs of _1-1 , _1-2 , _2-1 , and _2-2 , and the input signal is D _1-1 , D _1-2 , D _2-1 , D _2-2 . Separated into two signals and output. Among, D _1-1, D _1-2 signal is first 1EC
It is input to the C encoder 871a and sent to the main ECC encoder 872a and the sub ECC encoder 873a, respectively, where error correction coding is performed.

Here, the main ECC encoder 872a is the sub E
It has a stronger error correction capability than the CC encoder 873a. Therefore, as described in the graph of the CN-layer channel in FIG. 85, during demodulation and reproduction, the _D1-1 channel has a D / C value lower than that of the _D1-2 channel.
_1-1 can be reproduced below the standard error rate. D _1-1 is D
_It has a logical hierarchical structure that is more resistant to C / N reduction than _1-2 . The error-corrected D _1-1 and D _1-2 signals are combined by the combiner 874.
It is combined with the D ₁ signal at a and input to the modulator 4. On the other hand, the D _2-1 and D _2-2 signals are the second ECC encoder 871b.
Of the above, each of which is subjected to error correction coding by the main encoder 872b and the sub-ECC encoder 873b, is combined into a D ₂ signal by the combiner 874b, and is input by the modulator 4. The main ECC encoder 872b is the sub ECC encoder 873.
The error correction capability is higher than that of b. In this case, the modulator 4 is D
_A hierarchical modulation signal is created from _one signal and D ₂ signal, and the transmission unit 5
Sent by. As described above, the transmitter 1 of FIG. 87 has the two-layer physical layer structure of D ₁ and D ₂ by the modulation described in the first embodiment. This explanation has already been given. Next, by differentiating the error correction ability, D _1-1 and D _1-2 or D _2-1
Each of D _2-2 has a logical hierarchical structure of 2 layers.

Next, the state of receiving this signal will be described.
FIG. 88 is a block diagram of a receiver. The basic configuration of the second receiver 33 that receives the transmission signal of the transmitter of FIG. 87 is almost the same as the configuration of the second receiver 33 described in FIG. 21 of the first embodiment. The difference is that ECC decoders 876a and 876b are added. In this case, an example of QAM modulation / demodulation is shown, but the present invention can also be applied to an ASK signal such as a 4-valued or 8-valued VSB as shown in FIGS. 58 and 68A and 68B. Also,
PSK or FSK modulation / demodulation may be used.

In FIG. 88, the received signal is reproduced by the demodulator 35 as the D ₁ and D ₂ signals, and the separator 3
4 of D _1-1 , D _1-2 , D _2-1 and D _2-2 depending on a and 3b.
Two signals are generated and input to the first ECC decoder 876a and the second ECC decoder 876b. In a 1ECC decoder 876a, D _1-1 signal is mainly ECC decoder 8
The error is corrected by 77a and sent to the combining unit 37. On the other hand, the D _1-2 signal is error-corrected by the sub ECC decoder 878a and sent to the synthesizing unit 37. Similarly, the second ECC
The decoder 876b outputs the D _2-1 signal to the main ECC decoder 877b and the D _2-2 signal outputs to the sub ECC decoder 8
The error is corrected at 78b and input to the combining unit 37. The error-corrected D _1-1 , D _1-2 , D _2-1 and D _2-2 signals become a single signal in the synthesizing unit 37 and are output from the output unit 36.

In this case, D _1-1 is D due to the logical hierarchical structure.
_{Since the} error correction capability of _1-2 and D _2-1 is higher than that of D _2-2 , a predetermined error rate can be obtained even when the C / N value of the input signal is lower as described in FIG. , Can reproduce the original signal.

Specifically, the main ECC decoders 877a and 877b of High Code Gain and Low Cod are used.
A method of differentiating the error correction capability between the e-gain sub-ECC decoders 878a and 878b will be described. Vice EC
165 (b) ECC Decoder in the C decoder
In the case of using a standard inter-code distance coding method such as Reed-Solomon code or BCH code as shown in FIG. 1, the main ECC decoder uses a product code and a long code of both Reed-Solomon code and Reed-Solomon code. Method and Figure 128 (d)
(E) Trellis Decoders 744p and 744 shown in (f)
By using a coding method with a large inter-code distance for error correction using q and 744r, the error correction capability, that is, Cod
You can make a difference in e Gain. In this way, a logical hierarchical structure can be realized. Since various methods are known for increasing the inter-code distance, other methods will be omitted. The present invention can basically apply any method.

Further, as shown in the block diagrams of FIGS. 160 and 167, an interleaver 744K is provided in the transmission section and deinterleavers 759K and 936b are provided in the reception section.
By interleaving according to the Inter leave Table 954 of 68 (a) and decoding with the deinterleave RAM 936 × of the deinterleaver 936b, strong transmission against burst errors of the transmission system is possible and the image is stable.

Here, the logical hierarchical structure is shown in C / N of FIG.
And the error rate after error correction will be described with reference to the relationship diagram. In FIG. 89, a straight line 881 shows the relationship between the C / N of the D _1-1 channel and the error rate, and a straight line 882 shows D.
The relationship between the C / N of _1-2 channels and the error rate after correction is shown.

The smaller the C / N value of the input signal, the higher the error rate of the corrected data. Below a certain C / N value, the error rate after error correction does not fall below the reference error rate Eth at the time of system design, and the original data cannot be reproduced normally. When the C / N is gradually increased in FIG. 89, the D ₁ channel cannot be demodulated when the C / N is e or less as indicated by the straight line 881 of the D _1-1 signal. When e ≦ C / N <d, the D ₁ channel can be demodulated, but the error rate of the D _1-1 channel exceeds Eth, and the original data cannot be reproduced normally.

When C / N = d, since the error correction capability of D _1-1 is higher than that of D _1-2 , the error rate after error correction is point 8
As shown in 85d, it becomes equal to or lower than Eth, and the data can be reproduced. On the other hand, the error correction capability of D _1-2 is error rate after correcting for the error rate after correction for not high enough D _1-1 is not low enough D _1-1 can not be reproduced for greater than E ₂ and Eth. Therefore, in this case, only D _1-1 can be reproduced.

When C / N is improved and C / N = C,
After the error correction of D _1-2 , the error rate reaches Eth as shown at a point 885C, so that reproduction is possible. At this point, demodulation of D _2-1 and D _2-2, that is, D ₂ channel is in an uncertain condition. With the improvement of C / N, the D ₂ channel can be surely demodulated at C / N = b ′.

[0131] When the further C / N becomes improved C / N = b, decreased error rate of D _2-1 until Eth as shown in point 885B, D _2-1 will be able to play .
At this time, since the error rate of D _2-2 is higher than Eth, reproduction cannot be performed. C / N = error rate of D _2-2 as shown in the point 885a becomes a is the reduced D _2-2 channel until the Eth becomes possible play.

In this way, by using the differentiation of the error correction capability, the physical layer D ₁ and D ₂ channels are further divided into two logical layers, and a total of four layers can be transmitted. To be

In this case, the data structure has a hierarchical structure in which a part of the original signal can be reproduced even if high-layer data is lost, and by combining it with the multilevel transmission of the present invention, C / C like analog transmission can be achieved. There is an effect that hierarchical transmission in which the amount of data gradually decreases as N deteriorates becomes possible. In particular, since image compression technology has advanced rapidly in recent years, when image compression data is made into a hierarchical structure and combined with hierarchical transmission, images with much higher image quality than analog transmission can be transmitted between the same points, and at the same time, analog transmission can be performed. It can be received in a wide area while gradually lowering the image quality according to the received signal level as in transmission. In this way, it is possible to obtain the effect of hierarchical transmission, which has not been provided in conventional digital video transmission, while maintaining high image quality by digital.

Further, the address data of the image segment data, the reference image data at the time of image compression, the descrambling data shown in the lath scramble portion of FIG. High Priority Data D
_{As 1-1} , H of FIGS. 88, 133, 170, and 172
ECC Encorde of high code Gain
The high code of the receiver 43 is transmitted by r743a.
It is received by the gain ECC Decoder 758. In this method, even if the C / N deteriorates and the error rate of the signal increases, the High Priority Data
Since the error rate of D _1-1 does not increase so much, it is possible to prevent fatal image quality deterioration peculiar to digital video, and obtain the effect of Graceful Degradation, which often deteriorates the image quality. The modulating unit 749 and the demodulating unit 760 in FIGS. 133 and 170 are 4VSB of FIG. 57 and 8VSB of FIG. 68 which will be described in the fourth embodiment even in the above 16QAM and 32QAM.
But even with 8PSK Graceful Degradat
The effect of ion is obtained.

Further, as shown in FIGS. 133 and 156,
High Priority Data to 2nd da
ECC in ta stream input 744
Encoder 744a and Trellis Encod
er744b performs high code gain error coding, and sets Low Priority data to E.
Low code only with CC encoder743a
By performing error coding of the gain, H at the time of reception
high Priority data and LowPrio
It is possible to make a large difference in the error rate of the rity data. For this reason, since high priority data can be received even if the C / N is greatly deteriorated in the transmission system, the C / N is severely deteriorated in a receiver having bad reception conditions such as an automobile TV receiver. At the same time, due to the deterioration of Low Priority Data,
The image quality deteriorates. However, High Priority D
Since "ata" is reproduced, the arrangement information of the pixel blocks is reproduced, so that an image with degraded resolution and noise can be obtained without destroying the image, and the viewer can watch TV programs. The effect is obtained.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 29 is an overall view of the third embodiment. Example 3 shows an example in which the transmission device of the present invention is used in a digital TV broadcasting system. An input image 402 of ultra-high resolution is input to an input unit 403 of a first image encoder 401, and a separation circuit 404 outputs a first image. It is separated into a data string, a second data string, and a third data string, compressed by a compression circuit 405, and output.

The other input images 406, 407, 408 are compressed and output by the second image encoders 409, 410, 411 having the same structure as the first image encoder 401, respectively.

Of these four sets of data, the four sets of signals of the first data string are temporally multiplexed by the first multiplexer 413 of the multiplexer 412 by the TDM method or the like to form a first data string. , To the transmitter 1.

All or a part of the signal group of the second data string is multiplexed by the multiplexer 414 and sent to the transmitter 1 as the second data string. Further, all or part of the signal group of the third data string is multiplexed by the multiplexer 415,
It is sent to the transmitter 1 as a data string.

In response to this, in the transmitter 1, the three data strings are modulated by the modulator 4 as described in the first embodiment, and are transmitted to the satellite 10 by the transmitter 5 through the antenna 6 and the transmission path 7 and by the repeater 12. , The first receiver 23 and the like.

In the first receiver 23, the small-diameter antenna 22 having a radius r ₁ is received by the transmission path 21, and only the first data string in the received signal is reproduced by the first data string reproducing section 232.
Low resolution video outputs 425 and 4 such as NTSC signal or wide NTSC signal by the first image decoder 421.
26 is reproduced and outputted.

In the second receiver 33, the medium-diameter antenna 32 having a radius r ₂ is used to receive the first data string reproducing section 232 and the second data string reproducing section 232.
The data string reproducing unit 233 reproduces the first data string and the second data string, and the second image decoder 422 reproduces the HDT.
A high-resolution video output 427 or video output 425, 426 such as a V signal is reproduced and output.

In the third receiver 43, a large-diameter antenna 33 having a radius r ₃ is used to receive the first data string reproducing section 232 and the second data string reproducing section 232.
The data string reproducing unit 233 and the third data string reproducing unit 234 reproduce the first data string, the second data string, and the third data string, and reproduce the ultra high resolution HDTV such as an ultra high resolution HDTV for a video theater or a movie theater. The video output 428 is output. Video output 4
25, 4266, 427 can also be output. General digital TV broadcast is broadcast from the digital transmitter 51, and when received by the first receiver 23, is output as a low-resolution video output 426 such as NTSC.

Next, the configuration will be described in detail based on the block diagram of the first image encoder 401 in FIG. The ultra-high resolution video signal is input to the input unit 403 and sent to the separation circuit 404. The separation circuit 404 separates into four signals by the subband coding method. A horizontal low-pass filter 451 and a horizontal high-pass filter 452 such as QMF separate the components into a horizontal low-pass component and a horizontal high-pass component. The component is a horizontal low-pass vertical low-pass signal, abbreviated to H by a vertical low-pass filter 455 and a vertical high-pass filter 456.
_{The L VL} signal and the horizontal low frequency vertical high frequency signal, which are abbreviated as H _L V _H signals, are separated by the sub-sampling units 457 and 458.
The sampling rate is reduced and the data is sent to the compression unit 405.

The horizontal high frequency component is the vertical low pass filter 4
59 and a vertical high-pass filter 460 separate the signal into a horizontal high-frequency vertical low-frequency signal, which is abbreviated as H _{H VL} signal, and a horizontal high-frequency vertical low-frequency signal, which is abbreviated H _H L _H signal, and sub-sampling units 461 and 462. Then, the sampling rate is reduced and the data is sent to the compression unit 405.

In the compression unit 405, the H _L V _L signal is subjected to optimum compression such as DCT in the first compression unit 471 and the first output unit 472.
Is output as the first data string.

The H _L V _H signal is compressed by the second compression section 473 and sent to the second output section 464. The H _{H VL} signal is compressed by the third compression unit 463 and sent to the second output unit 464. H
_{The H} V _H signal is sent to the high resolution video symbol (H
_{H H} V _H 1) and an ultra-high resolution video signal (H _H V _H 2) are separated, and H _H V _H 1 is sent to the second output unit 464 and H _H V _H 2 is sent to the third output unit 468.

Next, referring to FIG. 31, the first image decoder 4
21 will be described. The first image decoder 421 receives the output from the first receiver 23, the first data string, that is, D _1, as the input unit 5
01 and the descrambling unit 502 descrambles it, and the decompression unit 503 decompresses it to the above-mentioned H _L V _L signal, and the screen ratio changing circuit 504 and the output unit 505 change the screen ratio to change the image of the NTSC signal. 506, NT
The SC signal outputs a striped screen image 507, a wide TV full screen image 508, or a wide TV side panel screen image 509. In this case, two scanning line types, non-interlaced or interlaced, can be selected. In the case of NTSC, 525 scanning lines and 1050 scanning lines by double writing can be obtained. Also, the digital transmitter 5
When the general digital TV broadcast of 4PSK from 1 is received, the TV image can be demodulated and reproduced by the first receiver 23 and the first image decoder 421. Next, the second image decoder will be described with reference to the block diagram of the second image decoder in FIG. First, the D ₁ signal from the second receiver 33 is input from the first input unit 521 and expanded by the first expansion unit 522,
The oversampling unit 523 doubles the sampling rate, and the vertical low-pass filter 524 causes H _L
The V _L signal is reproduced. The D ₂ signal is input from the second input unit 530 and separated into three signals by the separation circuit 531.
2nd extension part 532, 3rd extension part 533, and 3rd extension part 5
The vertical high-pass filter 5 is expanded and descrambled by the reference numeral 34, and the sampling rate is doubled by the oversampling units 535, 536, and 537.
38, a vertical low-pass filter 539, and a vertical high-pass filter 540. The H _L V _L signal and the H _L V _H signal are added by the adder 525, and the oversampling unit 54
1 and the horizontal low-pass filter 542 form a horizontal low-frequency video signal, which is sent to the adder 543. H _{H VL} signal and H
_{The H} V _H 1 signal is added by the adder 526, becomes a horizontal high-frequency video signal by the oversampling unit 544 and the horizontal high-pass filter 545, and is added by the adder 543 to the HDT.
A high-resolution video signal such as V becomes an HD signal, and the output unit 546 outputs an image output 547 such as HDTV. In some cases, the NTSC signal is also output.

FIG. 33 is a block diagram of the third image decoder. The D ₁ signal is input from the first input unit 521 and the D ₂ signal is input from the second input unit 530, and the HD signal is reproduced by the high frequency image decoder 527 by the above-described procedure. To be done. The D ₃ signal is input from the third input unit 551, expanded, descrambled, and synthesized by the super high frequency band image decoder 552 to reproduce the H _H V _H 2 signal. This signal is combined with the HD signal by the combiner 553 to become an ultra-high resolution TV signal and S-HD signal, and the output unit 5
An ultra high resolution video signal 555 is output from 54.

Next, a specific multiplexing method of the multiplexer 401 mentioned in the explanation of FIG. 29 will be described.

FIG. 34 is a data array diagram showing six NTSC channels L1, L2, L3, L4, L5 for the first data string, D ₁ and second data string, D ₂ and third data string D ₃ .
L6 and 6 HDTV channels M1 to M6 and 6 S
-Draws how to arrange HDTV channels H1 to H6 on the time axis during the period T. In FIG. 34, first, L1 to L6 are arranged in the D ₁ signal in the period T by time division multiplexing using the TDM method or the like. Domain 6 of D ₁
The H _{L VL} signal of the first channel is sent to 01. Next, in the domain 602 of the D ₂ signal, the difference information M1 between the HDTV and NTSC of the first channel in the time domain corresponding to the first channel, that is, the above-mentioned H _L V _H signal, H _H V _L signal, and H _H V _H
Send 1 signal. Also, the first in the domain 603 of the D ₃ signal
The super HDTV difference information H1 of the channel, that is, H _H V _H -2H1 described in FIG. 30 is sent.

Here, the case where the TV station of the first channel is selected will be described. First, a general receiver having the system of the small antenna, the first receiver 23, and the first image decoder 421 can obtain the NTSC or wide NTSC TV signal of FIG. Next, when a specific receiver having the medium-sized antenna, the second reception receiver 33, and the second image encoder 422 selects channel 1, the first data string, the domain 60 of D ₁
HD of the same program content as the NTSC program of channel 1 by synthesizing the 1st and 2nd data strings and the signal of domain D 602 of D _2.
Get TV signal.

Some receivers such as a movie theater having a large antenna, a third receiver 43 capable of multi-level demodulation, and a third image decoder 423 have a domain 601 of D ₁ and a domain 602 of D ₂ .
And the signal of the domain 603 of D ₃ is synthesized, and the channel 1
It obtains a super-resolution HDTV signal of movie quality with the same program content as NTSC. Other channels from 2 to 3 are reproduced in the same manner.

FIG. 35 shows another domain configuration. First, the first channel of NTSC is arranged in L1. This L1 is the domain 60 of the first time domain of the D ₁ signal.
It is located at position 1, and the head portion contains the information S11 including the descramble information between NTSCs and the demodulation information described in the first embodiment. Next, the first channel of HDTV is L1 and M
It is divided into 1 and entered. M1 is HDTV and NTSC
It is the difference information with respect to, and is included in both the domain 602 and the domain 611 of D ₂ . In this case 6 Mbps NT
When the SC compressed signal is adopted and accommodated in L1, the band of M1 is doubled to 12 Mbps. When L1 and M1 are combined, a band of 18 Mbps can be demodulated and reproduced from the second receiver 33 and the second image decoder 423. On the other hand, using the currently proposed compression method, HDTV in a band of about 15 Mbps
A compressed signal can be realized. Therefore, with the arrangement of FIG. 35, HDTV and NTSC can be simultaneously broadcast on channel 1. In this case, channel 2 cannot reproduce HDTV. S21 is HDTV descramble information. The super HDTV signal is divided into L1, M1 and H1 and broadcast. The difference information of Super HDTV uses the domains 603, 612 and 613 of D ₃ and NTSC of 6M.
When set to bps, a total of 36 Mbps can be sent, and if the compression is increased, a super HDTV signal of about 2000 scanning lines of image quality for movie theaters can also be transmitted.

The layout diagram of FIG. 36 shows the case where the super HDTV signal is transmitted by occupying 6 time domains in D ₃ . When the NTSC compressed signal is set to 6 Mbps 9
Double Mbps can be transmitted. Therefore, a higher quality Super HDTV can be transmitted.

The above is the case where one of the horizontal and vertical polarization planes of the radio wave of the transmission signal is used. Here, the frequency utilization efficiency is doubled by using two planes of polarization, horizontal and vertical. This will be described below.

FIG. 49 shows the horizontally polarized signal D _V1 of the first data string.
And the vertically polarized signal D _H1 and D _V2 and D of the second data string
A signal arrangement diagram of _H2 and D _V3 and D _H3 of the third data string is shown. In this case, the vertically polarized signal D _V1 of the first data string contains a low-frequency TV signal such as NTSC, and the horizontally polarized signal D _H1 of the first data string contains a high-frequency TV signal. Therefore, the first receiver 23 having only the vertically polarized antenna is the NTSC.
It is possible to reproduce low frequency signals such as. On the other hand, the first receiver 23 having vertically and horizontally polarized antennas is, for example, L ₁
And the M ₁ signal can be combined to obtain an HDTV signal.
That is, when the first receiver 23 is used, NTSC is used on the one hand and NTSC and HD on the other hand, depending on the capability of the antenna.
Since the TV can be played back, there is a great effect that the two systems are compatible with each other.

FIG. 50 shows a case where the TDMA system is used, and a synchronizing section 731 and a card section 741 are provided at the head of each data burst 721. A synchronization information section 720 is provided at the beginning of the frame. In this case, one channel is assigned to each time slot group. For example, in the first time slot 750, NTSC, HDTV, and Super HDTV of the same program on the first channel can be sent. Each time slot 7
50-750e is completely independent. Therefore, when a specific broadcasting station broadcasts in a TDMA system using a specific time slot, there is an effect that NTSC, HDTV, and super HDTV broadcasting can be performed independently of other stations. If the receiving side is a horizontally polarized antenna and the first receiver 23 is used, the NTSC TV signal is a dual polarized antenna and HDTV is used.
Can be played. When the second receiver 33 is used, low-resolution Super HDTV can be reproduced. With the third receiver 43, the super HDTV signal can be completely reproduced. As described above, it is possible to build a compatible broadcasting system. In this case, with the arrangement shown in FIG. 50, it is possible to perform time-division multiplexing of continuous signals as shown in FIG. 49 instead of the burst TDMA method.
Further, if the signal arrangement is as shown in FIG. 51, an HDTV signal having a higher resolution can be reproduced.

As described above, the third embodiment has a remarkable effect that ultrahigh resolution type HDTV, digital TV broadcasting compatible with three signals of HDTV and NTSC-TV can be realized. Especially when transmitted to a movie theater or the like, there is a new effect that the image can be digitized.

Here, the modified QAM according to the present invention is SRQ.
Called AM, a specific error rate will be described.

First, the error rate of 16SRQAM is calculated. FIG. 99 is a vector diagram of 16 SRQAM signal points. In the first quadrant, in the case of 16QAM, the intervals of 16 signal points such as the signal points 83a, 83b, 84a, 85, 83a are equal intervals, and are all 2δ.

The signal point 83a of 16QAM is I on the coordinate axis.
It is at a distance of δ from the axis and the Q axis. Here, in the case of 16 SRQAM, if n is defined as a shift value, the signal point 83a is shifted and the signal point 8 at the position of nδ is located from the coordinate axis.
Move to 3. In this case, n is 0 <n <3. Further, the other signal points 84a and 86a are also shifted and moved to the positions of the signal points 84 and 86.

If the error rate of the first data string is Pe1

[0165]

[Equation 1]

Let Pe2 be the error rate of the second data string.

[0167]

[Equation 2]

It becomes: Then 36 SRQAM or 32
Calculate the SRQAM error rate. 36 in FIG.
It is a signal vector diagram of SRQAM. In the first quadrant, the distance between signal points of 36QAM is defined as 2δ.

The signal point 83a of 36QAM is δ from the coordinate axis.
In the distance. When this signal point 83a reaches 36 SRQAM, it shifts to the position of the signal point 83, and has a distance of nδ from the coordinate axis. Each signal point is shifted to obtain signal points 83, 8
4, 85, 86, 97, 98, 99, 100, 101. The signal point group 90 composed of nine signal points is regarded as one signal point, is received by the modified 4PSK receiver, and the error rate when only the first data string D ₁ is reproduced is set to Pe1 and the signal point group 90 If the error rate in the case of discriminating each of the nine signal points in the above and reproducing the second data string D ₂ is Pe2,

[0170]

[Equation 3]

It becomes In this case, the C / N to error rate diagram of FIG. 101 shows an example of calculating the relationship between the error rate Pe and the C / N of the transmission system. Curve 900 shows the error rate of conventional 32QAM for comparison. Straight line 905
Indicates a straight line with an error rate of 10 −1.5. The first when the shift amount n of SRQAM of the present invention is 1.5
The error rate of the layer D ₁ is the curve 901a, and there is an effect that even if the C / N value is 5 dB lower than the 32QAM of the curve 900 at the error rate of 10 ^−1.5 , the D ₁ can be reproduced at the same error rate.

Next, the error rate of the second layer D ₂ when n = 1.5 is shown by the curve 902a. At an error rate of 10 ^−1.5 , reproduction cannot be performed at an equivalent error rate unless C / N is increased by 2.5 dB as compared with 32QAM shown by the curve 900. The curves 901b and 902b have n = 2.
D ₁ and D ₂ in the case of 0 are shown. Curve 902C shows D ₂ . To summarize this, the error rate is 10 -1.5
When the power value is 22n = 1.5, 2.0, 2.5,
Compared with 32QAM, D ₁ is improved by 5, 8, and ₁₀ dB, and D ₂ is deteriorated by 2.5 dB.

In the case of 32 SRQAM, when the shift amount n is changed, the first necessary for obtaining a predetermined error rate.
The C / N values of the data string D ₁ and the second data string D ₂ are shown in the relationship diagram of the shift amount n and C / N in FIG. As is clear from FIG. 103, if n is 0.8 or more, a difference in C / N value required for hierarchical transmission, that is, transmission of the first data string D ₁ and the second data string D ₂ , is generated, It can be seen that the effects of the present invention occur. Therefore, 32SRQAM is effective under the condition of n> 0.85. The error rate in the case of 16 SRQAM is as shown in the relationship diagram between C / N and error rate in FIG.

In FIG. 102, the curve 900 is 16QAM.
Indicates the error rate of. Curves 901a, 901b, 90
1c is n = 1.2, 1.5, respectively, of the first data string D ₁ .
The error rate for 1.8 is shown. Curve 902a,
902b, 902c each of the second data stream D ₂ n = 1.
The error rates for 2, 1.5 and 1.8 are shown.

The relationship diagram between the shift amount n and C / N in FIG. 104 shows that the first data string D ₁ required to obtain a specific error rate when the shift amount n is changed in the case of 16SRQAM.
And the C / N value of the second data string D ₂ .
As is apparent from FIG. 104, in the case of 16SRQAM, n>
It can be seen that if it is 0.9, the hierarchical transmission of the present invention is possible. From the above, if n> 0.9, hierarchical transmission is established.

Here, an example in which the SRQAM of the present invention is applied to the terrestrial broadcasting of a digital TV will be concretely shown. Figure 1
Reference numeral 05 shows a relationship diagram between the signal level and the distance between the transmitting antenna and the receiving antenna during terrestrial broadcasting. Curve 911 shows the signal level of the receiving antenna when the height of the transmitting antenna is 1250 ft. First, it is assumed that the required error rate of the transmission system required in the digital TV broadcasting system currently under study is 10 −1.5. Area 912
Indicates the noise level, and point 910 indicates the reception limit point of the conventional 32QAM system at the point where C / N = 15 dB.
Digital HDT at this point of L = 60 miles
V broadcasting can be received.

However, the C / N fluctuates with a width of 5 dB with time due to deterioration of receiving conditions such as weather. If the C / N drops in a reception situation where the C / N level is close to the threshold, the HD is suddenly increased.
I have a problem that I cannot receive TV. Also, due to the influence of topography and buildings, a fluctuation of at least about 10 dB is expected, and it cannot be received at all points within a radius of 60 miles. In this case, unlike analog, digital video cannot be completely transmitted. Therefore, conventional digital T
The service area of the V broadcasting system was uncertain.

On the other hand, in the case of 32SRQAM of the present invention or 8-VSB shown in FIG. 68, as shown in FIG.
The configuration of FIG. 137 has three layers. 1st to 1st layer D
_1-1 sends MPEG level low resolution NTSC signal,
It is possible to send medium resolution TV components such as NTSC on the 1-2nd layer D ₁ -2 and high frequency components of HDTV on the 2nd layer D ₂ . For example, in FIG. 105, the service area of the 1st and 2nd layers expands to the 70mile point as indicated by a point 910a, and the 2nd layer retreats to the 55mile point as indicated by 910b. The service area diagram of 32 SRQAM in FIG. 106 shows the difference in service area in this case.
FIG. 106 shows a computer simulation, and FIG.
3 is a more specific calculation of the service area diagram of FIG. Areas 708, 703c, and 703 in FIG.
a, 703b, 712 are each conventional scheme 32QAM service area of the service area of the 1-1 hierarchies D _1-1, first-
Service area of the two layers D ₁ -2, second service area of the hierarchy D _2, shows the service area of the neighboring analog stations. Of these, the conventionally disclosed data is used as the data of the conventional 32QAM service area.

In the conventional 32QAM broadcasting system, a nominal service area of 60 miles can be set. But,
Actually, the reception condition was extremely unstable near the reception limit area due to changes in weather and topographic conditions.

However, using the 36SRQAM of the present invention,
MPEG-1 grade low band TV component is transmitted on the 1-1 layer D _1-1 , NTSC grade mid band component is transmitted on the 1-2 layer D _1-2 , and HDTV high band TV is transmitted on the 2nd layer D _2. By transmitting the components, the radius of the service area of the HDTV of the high resolution grade is reduced by 5 miles as shown in FIG. 106, but the radius of the service area of the EDTV of the medium resolution grade is expanded by 10 miles or more, and the LDTV of the low resolution is increased. The service area will be expanded by 18 miles. FIG. 107 shows the shift factor n or s = 1.8.
The service area in the case of is shown, and FIG. 135 shows the service area of FIG. 107 by area.

As a result, firstly, in the conventional method,
By applying the SRQAM method of the present invention even in an unreceivable area that existed in an area with poor reception conditions,
At least within the set service area, it is possible to perform transmission so that almost all receivers can receive TV broadcasts with medium resolution or low resolution grade. Therefore, by using the present invention in an area where the reception of an area such as a building shadow or a lowland which occurs in normal QAM and an interference from an adjacent analog station occur, the area of the unreceivability is greatly reduced, and accordingly, the area of non-reception is substantially reduced. The number of recipients can be increased.

Secondly, in the conventional digital TV broadcasting system, only the receivers having expensive HDTV receivers and receivers can receive the broadcasts, so that only some receivers can watch the contents even in the service area. However, in the present invention, a receiver having a conventional TV receiver of the conventional NTSC, PAL, or SECAM system can add a digital receiver only, so that a program of digital HDTV broadcasting is NTSC grade or LDTV grade. This has the effect of enabling reception. Therefore, the recipient can watch the program with less financial burden.

At the same time, since the total number of receivers increases, the TV sender side can obtain more viewers, and the social effect that the management as the TV business becomes more stable is produced.

Thirdly, the area of the reception area of the medium and low resolution grade is expanded by 36% as compared with the conventional method when n = 2.5. The number of recipients increases with the expansion. Due to the expansion of the service area and the increase in the number of recipients, the business income of the TV operator increases accordingly. It can be expected that this will reduce the business risk of digital broadcasting and accelerate the spread of digital TV broadcasting.

Now, as shown in the service area diagram of 32SRQAM in FIG. 107, the same effect can be obtained when n or s = 1.8. By changing the shift value n, each broadcasting station can have HDTV receiver and NTSCTV
Depending on the conditions and circumstances peculiar to the region, such as the distribution status of the receivers, n
To the service area 70 of SRQAM D ₁ and D _2.
By setting 3a and 703b to the optimum conditions, the receiver can obtain the maximum satisfaction and the broadcasting station can obtain the maximum number of receivers.

In this case, when n> 1.0, the above effects are obtained. Therefore, 32SR
In the case of QAM, n is 1 <n <5. Similarly, in the case of 16 SRQAM, n is 1 <n <3.

In this case, in the SRQAM system for obtaining the first and second layers by shifting as shown in FIGS. 99 and 100,
If n is 1.0 or more in 16SRQAM, 32SRQAM, and 64SRQAM, the effect of the present invention can be obtained in terrestrial broadcasting.

In the embodiment, the case where the video signal is transmitted has been described, but the audio signal is divided into the high band portion or the high resolution portion and the low band portion or the low resolution portion, and the second data string and the first data string are respectively provided.
When transmitted using the transmission method of the present invention as a data string,
The same effect can be obtained.

When it is used for PCM broadcasting, radio and mobile phones, it has the effect of expanding the service area.

Further, in the third embodiment, as shown in FIG. 133, a subchannel by TDM is provided in combination with the time division multiplexing (TDM) system, and the ECC Encoder 74 is provided.
3a and 2 as shown in ECC Encoder 743b
By differentiating the error correction code gain of one sub-channel, it is possible to increase the number of sub-channels for multilevel transmission by making a difference in the threshold of each sub-channel. In this case, as shown in FIG. 137, 4VSB, 8VSB, 1
Code gain of ECC encoder such as Trellis Encoder for 2 subchannels of VSB-ASK signal of 6VSB
You may change s. The detailed description is the same as the description of FIG.

The block diagram of FIG. 131 is a magnetic recording / reproducing apparatus, and the block diagram of FIG. 137 is a transmitting apparatus. Up converter of the transmitter of the transmission device; Down of the receiver
By replacing the converters with the magnetic head recording signal amplification circuit and the magnetic head reproduction signal amplification circuit of the magnetic recording / reproducing apparatus, respectively, it can be seen that both have exactly the same configuration. Therefore, the configuration and operation of the modem unit are exactly the same. Similarly, it can be seen that the magnetic recording / reproducing system of FIG. 84 has the same configuration as the transmission system of FIG. 156.
If the structure is desired to be simple, the structure shown in FIG. 157 can be adopted. If it is desired to simplify the structure, the structure shown in FIG. 158 can be adopted.

In the simulation of FIG. 106,
A case where a difference of 5 dB in Coding Gain is provided between the 1-1 sub-channel D _1-1 and the 1-2 sub-channel D _1-2 is shown. SRQAM is a signal point code division multiplexing system (Constellation-Code Division) of the present invention called "C-CDM".
Multiplex) is applied to rectangle-QAM. C
-CDM is a multiplexing method independent of TDM and FDM. In this method, sub-channels are obtained by dividing the signal point code corresponding to the code. By increasing the number of signal points, it is possible to obtain the expandability of the transmission capacity that TDM and FDM do not have. This is achieved while maintaining almost complete compatibility with conventional equipment. As such, C-CDM has an excellent effect.

Although the embodiment in which C-CDM and TDM are combined is used, the same threshold relaxation effect can be obtained by combining the embodiment with frequency division multiplexing (FDM). For example, when it is used for TV broadcasting, it becomes as shown in the frequency distribution diagram of the TV signal of FIG. A conventional analog broadcasting signal, for example, an NTSC signal has a frequency distribution like a spectrum 725. The largest signal is video carrier 7
22. The color carrier 723 and the voice carrier 724 are not so large. In order to avoid mutual interference, there is a method of dividing a digital broadcast signal into two frequencies by FDM. In this case, as shown in FIG.
The interference can be reduced by dividing the carrier 727 and transmitting the first signal 720 and the second signal 721, respectively. First signal 7
By transmitting the low resolution TV signal with a large output by 20 and by transmitting the high resolution signal with a small output by the second signal 721, hierarchical broadcasting by FDM is realized while avoiding interference.

FIG. 134 shows a diagram when the conventional system 32QAM is used. Since the sub-channel A has a larger output, the threshold value Threshold1 may be 4 to 5 dB smaller than the sub-channel B threshold value Theshold2. Therefore, two-layer hierarchical broadcasting having a difference of 4 to 5 dB threshold is realized. However, in this case, the received signal level is
In the following cases, all of the shaded signals of the second signal 721a occupying a large amount of information cannot be received at all, and only the first signal 720a having a small amount of information can be received, and the second signal 720a cannot be received.
Only hierarchically poor quality images can be received.

However, in the case of using the present invention, as shown in FIG. 108, first, sub-channel 1ofA is added to the first signal 720 by using 32SRQAM obtained by C-CDM. A sub-channel 1ofA having a low threshold is loaded with a component having a lower resolution. 32S for the second signal 721
RQAM is set, and the threshold value of subchannel 1ofB is adjusted to the threshold value Thershold2 of the first signal. Then the signal level is Th
I cannot receive even if I go down to reshold-2. The area is only the second signal portion 721a indicated by diagonal lines, and since the subchannel 1ofB and the subchannel A can be received, the transmission amount does not decrease so much. Therefore, there is an effect that an image with good image quality can be received even at the signal level of Th-2 even in the second layer.

By transmitting the normal resolution component to one sub-channel, the number of layers is further increased and the low resolution service area is expanded. Voice information or synchronization information on the sub-channel with a low threshold,
By inserting important information such as the header of each data, this important information can be reliably received, and stable reception is possible. If a similar method is used for the second signal 721, the hierarchy of service areas increases. When the scanning line of HDTV is 1050 lines, in addition to 525 lines, C-CDM
Will add 775 service areas.

Thus, the combination of FDM and C-CDM has the effect of expanding the service area. In this case, two sub-channels are provided by FDM, but it is also possible to divide into three frequencies and provide three sub-channels.

Next, a method of combining TDM and C-CDM to avoid interference will be described. As shown in FIG. 109, the analog TV signal has a horizontal retrace line portion 732 and a video signal portion 731. The fact that the signal level of the horizontal retrace line portion 732 is low and that the signal is not output to the screen even if there is interference during this period is used. By synchronizing the synchronization of the digital TV signal with the analog TV signal, important data, for example, a synchronization signal or the like can be transmitted to the horizontal retrace line synchronization slots 733 and 733a in the period of the horizontal retrace line portion 732 or a large amount of data can be transmitted with a high output. it can.
This has the effect that the amount of data can be increased and the output can be increased without increasing interference. The same effect can be obtained by providing the vertical retrace line synchronization slots 737 and 737a in synchronization with the periods of the vertical retrace line portions 735 and 735a.

FIG. 110 is a principle diagram of C-CDM.
Further, FIG. 111 shows a code assignment diagram of the 16-QAM extended version C-CDM, and FIG. 112 shows a code assignment diagram of the 32QAM extended version. As shown in FIGS. 110 and 111, 256QAM has first, second, third and fourth layers 740a and 740.
It is divided into four layers, b, 740c, and 740d, and has 4, 16, 64, and 256 segments, respectively. 256 QAM signal point code word 742d of the fourth layer 740d
Is 8 bits “11111111”. This is 2b
four codewords 741a, 741b, 74 for each it
1c, 741d divided into first, second, third and fourth layers 740
a, 740b, 740c, 740d signal point region 742
“11” is assigned to each of a, 742b, 742c, and 742d,
“11”, “11”, and “11” are assigned. Thus,
Subchannels of 2 bits each, that is, subchannel 1, subchannel 2, subchannel 3, and subchannel 4 are formed. This is called a signal point code division multiplexing system. FIG. 111 shows a specific code arrangement of the 16QAM extended version, and FIG. 112 shows the 36QAM extended version. C-C
The DM multiplexing method is independent. Therefore, conventional frequency division multiplexing (FDM) and time division multiplexing (TD)
The combination with M) has the effect of further increasing the number of sub-channels. In this way, a new multiplexing method can be realized by the C-CDM method. Although C-CDM has been described using Rectangle-QAM, other modulation schemes having signal points, such as other forms of QAM, PSK, ASK, and the frequency domain can be regarded as signal points, and FSK can be similarly multiplexed.

For example, the error rate of sub-channel 1 of 8PS-APSK described above is

[0201]

[Equation 4]

Pe _{2-8 of} subchannel 2 is

[0203]

[Equation 5]

The error rate of 16-PS-APSK (PS type) sub-channel 1 is

[0205]

[Equation 6]

The error rate of sub-channel 2 is

[0207]

[Equation 7]

The error rate of sub-channel 3 is

[0209]

[Equation 8]

It can be expressed by. (Embodiment 4) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 37 is an overall system diagram of the fourth embodiment. The fourth embodiment uses the transmission device described in the third embodiment for terrestrial broadcasting and has substantially the same configuration and operation. Example 3
The difference from FIG. 29 described above is only that the transmitting antenna 6a is a terrestrial transmission antenna and that the antennas 21a, 31a, 41a of the respective receivers are terrestrial transmission antennas. is there. Since the other operations are exactly the same, the duplicated description will be omitted. Unlike satellite broadcasting, in the case of terrestrial broadcasting, the distance between the transmitting antenna 6a and the receiver is important. The receiver at a long distance has a weak arrival wave, and a conventional transmitter cannot demodulate at all with a signal simply multi-valued QAM-modulated, so that the program cannot be viewed.

However, when the transmission apparatus of the present invention is used, the first receiver 23 having the antenna 22a at a long distance as shown in FIG. 37 has a modified 64QMA modulated signal or modified 16QAM.
Since the modulated signal is received and demodulated in the 4PSK mode to reproduce the D1 signal of the first data string, an NTSC TV signal can be obtained. Therefore, even if the radio wave is weak, a TV program can be viewed with medium resolution.

Next, in the second receiver 33 having the antenna 32a in the middle distance, the arrival radio wave is sufficiently strong, so that the deformation 16 or 6 occurs.
The second data sequence and the first data sequence can be demodulated from the 4QAM signal to obtain an HDTV signal. Therefore, the same TV program in HD
You can watch it on TV.

On the other hand, the third receiver 43 having the antenna 42a at a short distance or having an ultra-high sensitivity has the first, second and third data strings D1 and D2 because the radio wave has sufficient strength for demodulating the modified 64QAM signal. , D3 are demodulated to obtain an ultra-high resolution HDTV signal. You can watch the same TV program on Super HDTV with the same image quality as a large movie.

The frequency allocation method in this case can be explained by replacing the time-multiplexed allocation with the frequency allocation using the diagrams of FIGS. 34, 35, and 36. When frequencies are allocated to channels 1 to 6 as shown in FIG. 34, D
NTSC L1 is the first channel for one signal, HDTV difference information is D3 for the first channel M1 of the D2 signal, and D3
By arranging the difference information of the ultra-high resolution HDTV in H1 of the first channel of the signal, NTSC, HDTV and super-resolution HDTV can be transmitted on the same channel. Also, as shown in FIG. 35 and FIG. 36, D2 of another channel
If the use of the signal or the D3 signal is permitted, a higher quality HDTV or an ultra high resolution HDTV can be broadcast.

As described above, three compatible digital TV terrestrial broadcasts can be broadcast using the D2 and D3 signal areas of one channel or another channel. In the case of the present invention, there is an effect that a TV program having the same content on the same channel can be received in a wider area if the resolution is medium.

As digital terrestrial broadcasting, HDTV broadcasting of 6 MHz band using 16QAM has been proposed.
However, since these systems are not compatible with NTSC, it is premised on the adoption of a simulcast system for transmitting the same program on another channel of NTSC. Also 16QAM
In this case, the service area that can be transmitted is expected to be narrowed. The use of the present invention for terrestrial broadcasting not only eliminates the need to provide another channel, but also has the effect of broadening the broadcasting service area because the program can be viewed with medium resolution even by a receiver at a long distance.

FIG. 52 shows an HDT of the conventionally proposed system.
FIG. 5 is a diagram showing a reception interference area at the time of digital terrestrial broadcasting of V, in which an analog broadcasting station 711 adjacent to a receivable area 702 capable of receiving HDTV from a digital broadcasting station 701 of HDTV using a conventionally proposed method can be received. A region 712 is shown. In the overlapping section 713 where the two overlap, due to the radio wave interference of the analog broadcasting station 711, at least HDTV cannot be stably received.

Next, FIG. 53 shows a reception interference area diagram when the hierarchical broadcasting system according to the present invention is used. In the present invention, when the transmission power is the same as that of the conventional method, the power use efficiency is low, and thus the high resolution receivable area 703 of HDTV is slightly narrower than the receivable area 702 of the conventional method. However, there is a low-resolution receivable area 704 such as digital NTSC that is wider than the receivable area 702 of the conventional method. It is composed of the above two areas. The radio interference from the digital broadcasting station 701 to the analog broadcasting station 711 in this case is at the same level as the conventional system shown in FIG.

In this case, the analog broadcasting station 71 is used in the present invention.
The disturbance from 1 to the digital broadcasting station 701 has three areas. One is the first jamming area 705 that neither HDTV nor NTSC can receive. The second is interference, but N
A second jamming area 706 in which the TSC can be received as before the jamming.
Is indicated by a single diagonal line. Here, since NTSC uses the first data string that can be received even if the C / N is low, the influence range of the interference is narrow even if the C / N is lowered due to the radio interference of the analog station 711.

Third, the third interference area 707 where HDTV could be received before the interference but only NTSC can be received after the interference.
Is indicated by a double diagonal line.

As described above, the H
The receiving area of DTV is slightly narrowed, but the receiving range including NTSC is widened. Further, due to the interference from the analog broadcasting station 711, even in the area where the HDTV could not be received due to the interference in the conventional method, the same program as the HDTV is NT.
It can be received by SC. Thus, there is an effect that the unreceivable area of the program is greatly reduced. In this case, by slightly increasing the transmission power of the broadcasting station, the receivable area of HDTV becomes equivalent to that of the conventional system. Furthermore, in the distant area where the conventional system cannot watch the program at all, or in the overlapping area with the analog station, the program can be received with the quality of NTSC TV.

Although the example using the two-layer transmission system is shown, the three-layer transmission system may be used as shown in the time allocation diagram of FIG. By separating HDTV into images of three levels of HDTV, NTSC, and low-resolution NTSC and transmitting the images, the receivable area in FIG. 53 is expanded from two layers to three layers, and the outermost layer is a wide area, and in two-layer transmission. In the first obstruction area 705 that cannot be received at all, a program can be received with the quality of low resolution NTSC TV. The above shows an example in which a digital broadcasting station interferes with analog broadcasting.

Next, an embodiment under the regulation condition that digital broadcasting does not interfere with analog broadcasting will be described.
The method of utilizing an empty channel, which is currently being considered in the United States, uses the same channel adjacently. Therefore, digital broadcasting to be broadcast later must not interfere with existing analog broadcasting. Therefore, it is necessary to lower the transmission level of digital broadcasting as compared with the case of transmission under the conditions of FIG. In this case, in the case of conventional 16QAM or 4ASK modulation, the unreceivable area 713 indicated by the double diagonal lines is large as shown in the interference state diagram of FIG. . The service area becomes smaller, and the number of recipients decreases accordingly, so the number of sponsors decreases. Therefore, it is expected that the broadcasting system will not be economically viable with the conventional method.

Next, FIG. 55 shows the case where the broadcasting system of the present invention is used. The high resolution receivable area 703 of HDTV is
It is slightly narrower than the receivable area 708 of the conventional method. However, a low-resolution receivable area 704 such as NTSC having a wider range than the conventional method can be obtained. The part shown with a single diagonal line cannot receive the same program at the HDTV level.
Indicates the area that can be received at the level. Of these, in the first interference area 705, interference from the analog broadcasting station 711 is received, and neither HDTV nor NTSC can be received.

As described above, in the case of the same radio field intensity, the coverage area of HDTV quality is slightly narrowed in the layered broadcasting of the present invention, while the area where the same program can be received in NTSCTV quality is increased. This has the effect of increasing the service area of the broadcasting station. This has the effect of providing the program to more recipients. It is possible to establish an HDTV / NTSCTV broadcasting business more economically and stably.
In the future, when the ratio of digital broadcasting receivers increases, the interference rule for analog broadcasting will be relaxed, so the radio field strength can be increased. At this point, the HDTV service area can be enlarged. In this case, by adjusting the interval between the signal points of the first data string and the second data string,
The receivable area of the digital HDTV INTSC and the receivable area of the digital NTSC shown in 5 can be adjusted. In this case, by transmitting the information of this interval to the first data string as described above, it is possible to receive more stably.

FIG. 56 shows an interference situation diagram when switching to digital broadcasting in the future. In this case, unlike FIG. 52, the adjacent station is the digital broadcasting station 701a that performs digital broadcasting. Since the transmission power can be increased, the high resolution receivable area 703 such as HDTV can be expanded to the receivable area 702 equivalent to analog TV broadcasting.

Then, the competition area 71 of both receivable areas
In the case of No. 4, the programs cannot be reproduced in the quality of HDTV by the normal directional antenna because they interfere with each other, but the program of the digital broadcasting station in the direction of the receiving antenna is N
It can be received in TSCTV quality. Further, when an antenna having a very high directivity is used, a program of a broadcasting station in the directivity direction of the antenna can be received with HDTV quality. The low-resolution coverage area 704 is wider than the standard coverage area 702 of analog TV broadcasting, and in the competition areas 715 and 716 of the low-resolution coverage area 704a of the adjacent broadcasting station, the broadcasting stations in the directivity direction of the antenna. Program is NTSCTV
It can be reproduced with the quality of.

[0229] Now, in the fairly widespread period of digital broadcasting in the future, the regulatory conditions will be further relaxed, and the hierarchical multilevel broadcasting of the present invention will allow HDTV to have a wide service area.
Broadcasting is possible. Even at this point, by adopting the layered multi-level broadcasting system of the present invention, a wide range of HDTV reception range can be secured as much as the conventional system, and a far region or a competing region that cannot be received by the conventional system. Also, since the program can be received with the quality of NTSCTV, the effect that the defective portion of the service area is greatly reduced is obtained.

(Embodiment 5) Embodiment 5 is an embodiment in which the present invention is applied to amplitude modulation, that is, ASK system. FIG. 57 shows a 4-valued VSB-ASK signal signal point arrangement diagram of Embodiment 5. It has four signal points 721, 722, 723, 724. FIG. 68 (a) shows an 8-value VSB signal Constel.
shows the relation. In case of 4 values, 2 bit data, 8
In the case of a value, 4-bit data can be sent in one cycle. In case of 4VSB, signal points 721, 722, 723,
724 can correspond to 00, 01, 10, 11, for example.

In order to perform multi-valued transmission according to the present invention, as shown in the signal point arrangement diagram of 4 level ASK such as 4 level VSB in FIG. Treat the signal points 723 and 724 as another group, the second signal point group 7
It is defined as 26. Then, the interval between the two signal point groups is made wider than the interval between the equally-spaced signal points. That is, signal point 72
Spacing apart of the signal points 723 and 724 when the L of 1,722 good at the same L but distance L _o of the signal point 722 and signal points 723 is set larger than L.

That is, L _o > L is set. This is a feature of the hierarchical multilevel transmission system of the present invention. However it may become temporarily or permanently L = L _o by the conditions and settings, depending on the design of the system. In the case of 8-value VSB, Constella as shown in FIGS. 68 (a) and 68 (b)
It becomes a section.

As shown in FIG. 59 (a), the two signal point groups can be associated with the 1-bit data of the first data string D ₁ . For example, if the first signal point group 725 is 0,
If the signal point group 726 of 1 is defined as 1, 1 of the first data string
A bit signal can be defined. Next, 1 of the second data string D ₂
The signal of bit is made to correspond to two signal point groups in each signal group. For example, as shown in FIG. 59B, signal points 721, 7
23 and D ₂ = 0, the signal point 722 and 724 can define data D ₂ = 1 Tosureba second data stream D _2. In this case as well, the number is 2 bits / symbol.

By arranging the signal points in this way,
The multilevel transmission of the present invention is possible with the ASK method. The hierarchical multilevel transmission system is no different from the conventional equidistant signal point system when the signal-to-noise ratio, that is, the C / N value is sufficiently high. However, when the C / N value is low, the second data string D ₂ cannot be reproduced by using the present invention, but the first data string D ₁ can be reproduced under the condition that the conventional method cannot reproduce the data at all. To explain this, the state in which the C / N has deteriorated can be shown as in the signal point arrangement diagram of 4VSB-ASK in FIG. That is, the signal points reproduced by the receiver are dispersed signal point areas 721a722a,
23a and 724a are dispersed in a Gaussian distribution. In such a case, distinction between the signal point 721 and the signal point 722 by the slice level 2 by the four-value slicer,
It becomes difficult to distinguish the signal point 723 and the signal point 724 by the slice level 4. That is, the error rate of the second data string D ₂ becomes very high. However, as is clear from the figure, the group of signal points 721 and 722 and the signal points 723 and 72
It is easy to distinguish from the 4 groups. That is, the first signal point group 725 and the second signal point group 726 can be distinguished.
Therefore, the first data string D ₁ can be reproduced at a low error rate.

In this way, the data strings D ₁ and D _{2 of the} two layers can be transmitted and received. Thus both in good condition and the region of C / N of the transmission system of the first data stream D ₁ and the second column D ₂ is C /
In a bad state of N and in an area, there is an effect that multi-valued transmission in which only the first data string D ₁ is reproduced can be performed.

FIG. 61 is a block diagram of the transmitter 741. The input unit 742 is composed of a first data string input unit 743 and a second data string input unit 744. The carrier wave from the carrier wave generator 64 is amplitude-modulated in the multiplier 746 by the input signal obtained by combining the signals from the input unit 742 in the processing unit 745,
It becomes a 4-valued or 8-valued ASK signal as shown in FIG. The 4ASK or 8ASK signal is band-limited by the bandpass filter 747, as shown in FIG.
Side Ba with a little residual carrier like
Vestigial Side Band with nd, that is, A of VSB signal
The SK signal is output from the output unit 748.

The output waveform after passing the filter will be described. FIG. 62 (a) is a frequency distribution diagram of the ASK modulation signal. There are sidebands on both sides of the carrier as shown. A bandpass filter of the filter 747 is used to remove the sideband on one side while leaving a carrier component a little like a transmission signal 749 in FIG. 62 (b). This is called VSB signal, but when the f ₀ and modulation frequency band, since that can be transmitted in a frequency band of about f _0/2, it is known that spectrum efficiency is good. The ASK signal of FIG. 60 originally has 2 bits / symbol, but when the VSB method is used, it is 4 VSB and 8 VS.
B is 4Qi of 16QAM and 32QAM in the same frequency band
An information amount corresponding to 5 bits / symbol of t / symbol can be transmitted.

Next, in the VSB receiver 751 shown in the block diagram of FIG. 63, the signal received by the antenna 32a on the ground is mixed in the mixer 753 with the signal from the variable oscillator 754 which is changed by channel selection via the input section 752. And converted to a lower intermediate frequency. Next, it is detected by the detector 755 and becomes a baseband signal by the LPF 756, and in the case of 4VSB, a Slicer of 4level,
In the case of 8VSB, the first data string D ₁ and the second data string D ₂ are reproduced by the identification and regenerator 757 having a slicer of _{8 level} and are output from the first data string output unit 758 and the second data string output unit 759.

Next, a case where a TV signal is sent using this transmitter and receiver will be described. FIG. 64 shows a video signal transmitter 774.
It is a block diagram of. A high-resolution TV signal such as an HDTV signal is input to the input unit 403 of the first image encoder 401, and a video separation circuit 404 such as a sub-band filter _{HL VL} , _HL V _H , H _{H VL} , H. It is separated into high-frequency TV signal and a low TV signal such as _H H _H. Since the contents have been described in the third embodiment with reference to FIG. 30, detailed description thereof will be omitted. The separated TV signal is encoded in the compression unit 405 using a method such as DPCMDCT variable length encoding used in MPEG or the like. Motion compensation is processed at the input 403. The four compressed image data are combined by the synthesizer 771 into the first data string D ₁ and the second data string D ₂ .
It becomes one data string. In this case H _L V _L signal that is an image signal of low frequency is included in the first data stream. The first data string input unit 743 and the second data string input unit 744 of the transmitter 741
The signal is input to the signal A, and is subjected to amplitude modulation, becomes an ASK signal such as VSB, and is broadcast from the ground antenna.

FIG. 65 is a block diagram of the entire TV receiver for this digital TV broadcast. The broadcast signal received by the terrestrial antenna 32a is input to the input unit 752 of the receiver 751 in the TV receiver 781, and the detection demodulator 760 selects and demodulates a signal of an arbitrary channel desired by the receiver. The first data sequence D ₁ and the second data sequence D ₂ are reproduced and the first data sequence D ₁ is reproduced.
It is output from the data string output unit 758 and the second data string output unit 759. Detailed explanation is omitted because it overlaps. The D ₁ and D ₂ signals are input to the separation unit 776. D ₁ signal is a separator 77
The H _L V _L compressed component separated by 7 is input to the first input unit 521. The other is combined with the D ₂ signal by the combiner 778 and input to the second input section 531. In the second image decoder, the H _L V _L compressed signal that has entered the first input unit 521 is
The first decompression unit 523 decompresses the signal into an H _L V _L signal and sends it to the image composition unit 548 and the screen ratio changing circuit 779. Original T
If the V signal is an HDTV signal, the H _{L VL} signal is a wide N signal.
If it becomes a TSC signal and the original signal is an NTSC signal, M
Low resolution TV with lower quality than NTSC like PEG1
Become a signal.

[0241] In order to have set the original video signal HDTV signal and in this description, T of H _L V _L signal is wide NTSC
It becomes the V signal. If the screen aspect ratio of the TV is 16: 9, the screen ratio of 16: 9 is output as the video output 426 via the output unit 780. If the screen aspect ratio of the TV is 4: 3, the screen ratio changing circuit 779 changes the screen aspect ratio from 16: 9 to 4: 3 to the letterbox format or the side panel format, and outputs it via the output unit 780. It is output as a video output 425.

On the other hand, the second data string D ₂ from the second data string output unit 759 is combined with the signal of the separator 777 in the combiner 778 of the separation unit 776, and is supplied to the second input unit 531 of the second image decoder. Is input and H is output by the separation circuit 531.
_L V _H , H _{H VL} , H _H V _H
Decompression unit 535, the third extension portion 536, is sent to the fourth extension portion is extended original _{H L V H, H H V} L, the _H H V _H signal. The H _L V _L signal is applied to these signals, the image synthesizing unit 54
8 to be combined into a single HDTV signal, which is output from the output unit 546 and HDT via the output unit 780.
It is output as a V video signal 427.

The output section 780 is the second data string output section 7
The error rate of the second data string of 59 is the error rate detection unit 782.
When the error rate is high for a certain period of time, the low-resolution image signal of the H _L V _L signal is automatically output for a certain period of time, the image output is stopped, the filter is activated, Issue control commands for the system such as regaining synchronization.

As described above, it is possible to transmit and receive the layered broadcast. When the transmission conditions are good, for example, for a broadcast having a TV transmission antenna close to it, both the first data string and the second data string can be reproduced, so that the program can be received in HDTV quality. For broadcasting with a long distance from the transmitting antenna, the first data string is reproduced, and a TV signal of low resolution is output from this V _L H _L signal. This makes HD
There is an effect that the same program can be received in a wider area with TV grade or NTSC TV grade.

Also, as shown in the block diagram of the TV receiver of FIG. 66, if the function of the receiver 751 is reduced to only the first data string output section 768, the receiver does not have to handle the second data string and the HDTV signal. The structure can be greatly simplified. As the image decoder, the first image decoder 421 described in FIG. 31 may be used. In this case NTSCTV
An image of the quality of is obtained. Although the quality of HDTV cannot receive a program, the cost of the receiver is significantly reduced. Therefore, it may be widely used. In this system, the conventional T
Many TV systems with V displays can be added as adapters without modification to digital TV
The effect is that broadcasts can be received.

When receiving the scrambled 4VSB and 8VSB signals as shown in FIG.
The descrambler 502b of the descrambler 502c of the descrambler 502 and the descrambling signal transmitted by the B, 8VSB signal are collated by the descramble number collator 502b.
By canceling escramble, the scramble of a specific scrambled program can be properly cancelled.

With the configuration shown in FIG. 67, a receiver having the functions of a satellite broadcast receiver for demodulating a PSK signal and a terrestrial broadcast receiver for demodulating a VSB signal can be easily constructed. In this case, the PSK signal received from satellite antenna 32 is mixed with the signal from oscillator 787 in mixer 786,
It is converted into a low frequency and inputted into the input unit 34 of the TV receiver 781 and inputted into the mixer 753 described in FIG. 63. The PSK or QAM signal converted into the low frequency of the specific channel of the satellite TV broadcast is demodulated by the demodulation unit 35 into the data strings D ₁ and D ₂ , and the second image encoder 422 transmits the image signal through the separation unit 788. And is output from the output unit 780. On the other hand, the digital terrestrial broadcasting and the analog broadcasting received by the terrestrial antenna 32a are input to the input unit 752, a specific channel is selected by the mixer 753 by the same process as described in FIG. It becomes a baseband signal only in the range. The analog satellite TV broadcast is input to the mixer 753 and demodulated. In the case of digital broadcasting, the identification reproducer 757 reproduces the data strings D ₁ and D _2, and the second image decoder 42
2, the video signal is reproduced and output. When receiving analog TV broadcasts from the ground and satellite, the video demodulation unit 7
The analog TV signal AM-demodulated by 88 is output from the output unit 7
It is output from 80. When the configuration of FIG. 67 is taken, the mixer 75
3 can be shared by satellite and terrestrial broadcasting. The second image decoder 422 can also be shared. Also, in digital terrestrial broadcasting A
When the SK signal is used, the receiver circuit such as the detector 755 and the LPF 756 similar to the conventional analog broadcast can be used for AM demodulation. As described above, the configuration of FIG. 67 has the effect of largely sharing the receiving circuit and reducing the number of circuits.

Further, in the embodiment, the 4-level ASK signal is divided into two groups, and multi-level transmission of 1 bit for each of the two layers D ₁ and D ₂ is performed. However, the 8VSB shown in FIGS.
8-value A shown in the signal Constellation diagram
If SK signal, that is, 8level-VSB is used, D ₁ ,
A total of 3 bits / symb for each 1 bit of 3 layers of D ₂ and D _3.
It is possible to perform multi-valued transmission of ol. As shown in FIG. 68 (a), the way of assigning the first bit code is first described. The signal points of the D ₃ signal are the signal points 721a, 721b, and 7b.
22a and 722b, 723a and 723b, 724a and 7
It is a binary value of 24b, that is, 1 bit. Next 1 bit
The coding of the signal points of D ₂ is the signal point group 721.
And 722, binary 1 bit of signal point groups 723 and 724
Is. The data of D ₃ is 2 of the large signal point groups 725 and 726.
The value is 1 bit. In this case, the four signal points 721, 722, 723, and 724 in FIG.
21a and 721b, 722a and 722b, 723a and 7
23b, 724a, and 724b are separated, and the distance between each group is increased to enable hierarchical multilevel transmission of up to three layers. As described above, L = L ₀ can be set.

[0249] Using the three-layer multi-level transmission system to perform three-layer digital HDTV video transmission is the third embodiment.
The detailed description of the operation will be omitted.

[0250] Here, the TV by the 8-value VSB in FIG.
The effect of broadcasting is described. Although 8VSB has a large amount of transmission information, the error rate for the same C / N value is higher than 4VSB. However, when performing high-definition HDTV broadcasting, since there are plenty of transmission capacities and a large number of error correction codes are included, the error rate can be reduced and hierarchical TV broadcasting can be performed in the future.

Here, the effects of 4VSB, 8VSB and 16VSB will be described while comparing them. When terrestrial broadcasting is performed using the NTSC or PAL frequency band, as shown in FIG. 136, in the case of NTSC, there is a band limitation of 6 MHz and about 5 MHz.
A substantial transmission band of MHz is allowed. In the case of 4VSB, since the frequency utilization efficiency is 4bit / Hz, there is substantially a data transmission capacity of 5MHz × 4 = 20Mbps. On the other hand, transmission of a digital HDTV signal requires at least 15 Mbps to 18 Mbps. Therefore, 4
-Since VSB has no margin in data capacity, as shown in the comparison diagram of FIG.
Only 10 to 20% of the actual transmission amount of TV can be obtained.

Next, in the case of 8-VSB, since the frequency utilization efficiency is 6 bits / HZ, 5 MHz × 6 = 30 Mbps.
The data transmission capacity of is obtained. As described above, transmission of HDTV signals requires 15 to 18 MHz, but 8VSB
In the case of the modulation method, as shown in FIG. 169, the information amount of 50% or more of the actual transmission amount of the HDTV signal can be used for the error correction code. Therefore, HDT with the same data rate
Under the condition that the V digital signal is terrestrially broadcast in the band of 6 MHz, since 8VSB can add a larger capacity error correction code, as shown in error rate curves 805 and 806 of FIG. T for which Code Gain for error correction is increased for the same C / N value of
The CM-8VSB has an error rate after error correction lower than that of 4VSB having a low code gain for error correction. Therefore, 8VSB error-coded by High coda gain has the effect of expanding the service area in TV terrestrial broadcasting as compared with 4VSB.
Certainly, 8VSB has a drawback that the circuit of the receiver becomes more complicated due to the increase of error correction circuits. But VSB
Since the ASK method is the amplitude modulation method, Q including the phase component
Compared with the AM modulation method, the equalizer of the receiver is originally used.
The circuit scale of r is extremely small. Therefore, even if an error correction circuit is added, the overall circuit scale is 32 in the 8VSB system.
It does not become larger than the QAM method. Therefore, 8VSB
According to the method, a digital HDTV receiver having a wide service area and an appropriate circuit scale is realized.

A concrete example of the error correction method will be described later in the fifth embodiment and the like, but the transmitter / receiver blocks of FIG. 84, the sixth embodiment, FIGS. 131, 137, 156 and 157. ECC744a and Trellis Enc shown
Using the oder 744b, 4VSB described in FIG. 61,
Transmission is performed using the VSSB modulation unit 749 of 8 VSB and 16 VSB. On the receiver side, the VSB demodulation unit 760 described with reference to FIG.
Lev of 4, 8 or 16 values from B or 16 VSB signal
The digital data is reproduced by the el slicer 757, and also FIG. 84 and the sixth embodiment which will be described later in the fifth embodiment and the like.
131, 137, 156, and 157 of FIG.
lis Decoder 759b and ECC Decode
After performing error correction by the er 759a, the image expander of the image decoder 402 reproduces and outputs the digital HDTV signal.

The ECC Encoder 744a has an R value as shown in FIGS. 160 (a) and 160 (b) described in the sixth embodiment.
ed solomon Encoder 744j and I
ECC Dec using the interleaver 744k
DeInterleaver75 for oder759a
9k and Reed solomon Decoder75
9j is used. Interl as described in the previous example
Burst error becomes strong by applying eave.

128 (a) (b) (c) (d) (e)
By adopting the Trellis encoder shown in (f), Code Gain can be further increased, and the error rate is reduced. In case of 8VSB, FIG. 172
Ratio2 / 3 Trellis en as shown in
Coder 744b and decoder 759b can be applied.

The embodiments have been described mainly using an example of transmitting a hierarchical digital TV signal. In the case of the hierarchical type, ideal broadcasting can be performed, but the circuit of the image compression circuit and the modulator / demodulator becomes complicated, which is not preferable in terms of cost at the start of broadcasting. As described at the beginning of Example 5, 4VSB or 8VS
The non-hierarchical TV transmission is performed by setting the signal point intervals of B to L = L _0, that is, at equal intervals, and as shown in FIG.
With a simple structure, a TV broadcasting system with a simple circuit is realized. And 8VSB at the stage of popularization
It is sufficient to switch to the hierarchical transmission of.

The 4VSB and 8VSB have been described above. In FIGS. 159 (a) to 159 (d), 16VSB and 3VSB have been described.
2VSB will be described. 159 (a) shows 16VS
B shows the constellation. Fig. 159
(B) is grouped into two signal point groups 722a to 722h, and is regarded as eight signal points.
Since it can be handled as an SB, a two-layer hierarchical multilevel transmission is realized. In this case Time Division Malti
Hierarchical transmission can be realized even if the 8VSB signal is intermittently transmitted by plex. However, in this method, the maximum data rate becomes 2/3. In FIG. 157 (c), there are four groups 723a to 723d, which are treated as 4VSB, so that the number of layers further increases by one layer. In this case as well, Time Divi
Even if the 4VSB signal is transmitted intermittently by the sion multiplex, the maximum data rate is reduced, but the hierarchical transmission is realized. With the above, a three-layer hierarchical VSB is realized.

This system realizes the hierarchical transmission in which the data of 8VSB or 4VSB can be reproduced when the C / N of 16VSB becomes worse. Also, FIG.
By doubling the 16VSB signal points as shown in (d), 32VSB can be transmitted. When it is desired to increase the capacity of 16 VSB in the future, this method has an effect that a data capacity of 5 bit / symbol can be obtained while maintaining compatibility.

The above description is summarized in FIG.
162 and the receiver shown in the block diagram of the VSB receiver of FIG.
The configuration of the transmitter is shown in the block diagram of the VSB transmitter.

Although the description has been made mainly using 4-VSB and 8-VSB, 16VS as shown in FIGS. 159 (a) (b) (c).
It is also possible to transmit using B. In the case of 16 VSB, when performing terrestrial broadcasting, a transmission capacity of 40 Mbps can be obtained in a band of 6 MHz. However, the data rate of the HDTV digital compressed signal is 15 to 18 when the MPEG standard is used.
Since it becomes Mbps, the margin of the transmission capacity becomes too large. As shown in FIG. 169, Redundancy: R ₁₆
= 100% or more, 1-channel digital HDT
Redundancy becomes too large to transmit V, and the circuit becomes complicated, but it is less effective for 8VSB. And 16VS for 2 channel HDTV terrestrial broadcasting
If it is B, the redundancy is the same as 4VSB and only about 10b can be taken, so that a sufficient error correction code cannot be inserted, and the service area becomes narrow. 4-V as described above
In SB, Redundancy: R ₄ = 10 to 20%, and sufficient error correction cannot be performed, so that the service area cannot be wide. As is clear from FIG. 169, sufficient error correction coding can be performed with 8-VSB Redundancy: R ₈ = 50%. The service area can be taken without increasing the circuit scale for error correction. Therefore digital H
Under the condition that the DTV terrestrial broadcasting is limited to a band of 6 to 8 MHz, as is clear from FIG. 169, 8 Level
It can be seen that -VSB is the most effective and optimal VSB modulation method.

Although the image encoder 401 as shown in FIG. 30 has been described in the third embodiment, the block diagram of FIG. 30 can be rewritten as shown in FIG. 69. Since the contents are exactly the same, the description is omitted. As described above, the image encoder 401 includes the video separation circuit 40 such as a subband filter.
It has two 4 and 404a. When these are referred to as a separating unit 794, they are shown in the block diagram of the separating unit in FIG. 70. Thus, the circuit can be eliminated by passing the signal through one separation circuit twice in a time division manner. To explain this, in the first cycle, the video signal of HDTV or super HDTV from the input unit 403 is compressed on the time axis by the time axis compression circuit 795 and separated by the separation circuit 404 to H _H V _H -H, H _H V. _L- H, _HL V _H-
H, divided into four components H _L V _L +1. in this case,
Switch 765,765a, 765b, 765c is in the first position, the compression unit _{405, H H V H -H,} H H V L -
H, outputs three signals of _{H L} V H -H. But _HL
The _VL- H signal is input from the output 1 of the switch 765c to the input 2 of the time axis adjustment circuit 795, and is sent to the separation circuit 404 in the idle time of the second cycle, that is, the time division processing, and is subjected to the separation processing H _H V _H , It is divided into four components, H _{H VL} , H _L V _H , and H _{L VL} , and output. Switch 76 in the second cycle
Since 5, 765a, 765b, and 765c change to the position of the output 2, the four components are sent to the compression unit 405. By thus adopting the configuration of FIG. 70 and performing time division processing, there is an effect that the number of separation circuits can be reduced.

Next, when such three-layer hierarchical image transmission is performed, an image decoder as described in the block diagram of FIG. 33 of the third embodiment is required on the receiver side. By rewriting this, a block diagram as shown in FIG. 71 is obtained. Although there are different processing capabilities, there are two combiners 566 having the same configuration.

If this is adopted in the configuration shown in FIG.
This can be realized by one combiner as in the case of the separation circuit of. Referring to FIG. 72, five switches, 765a,
First, at timing 1, the switches 765, 765a, 765b, and 765b, 765c, and 765d are used.
The input of 765c switches to 1. Then, first extending portion 522, a second extending portion 522a, the third extension portion 522b, each H _L V _L from the fourth extension portions _{522c, H L V H, H} H V L, H
The signal of _H V _H is input to the corresponding input section of the combiner 556 through the switch and is combined to form one video signal. This video signal is sent to the switch 765d and output 1
And output again to the input 2 of the switch 765c.
This video signal is originally a signal of H _L V _L -H components obtained by dividing a high resolution video signal. At the next timing 2, the switches 765, 765a, 765b, 765c are switched to the input 2. Thus, in turn, _{H H} V _H -H, _{H H
V L -H, H L V H} -H , and H _L V _L -H signal combiner 5
It is sent to 56 and is subjected to a synthesis process to obtain one video signal. This video signal is output from the output unit 554 from the output 2 of the switch 765d.

In this way, when receiving a three-layer hierarchical broadcast, there is an effect that the number of two combiners is reduced to one by time division processing.

In this system, first, at timing 1, the H _H V _H , H _H V _L , H _L V _H , and H _L V _L signals are input, and H
The _L V _L -H signal is synthesized. Then, at a timing 2 other than the timing 1, H _H V _H −H, H _H V _L −
The procedure is such that the H, _HL V _H- H and the _{HL VL-} H signal are input to obtain the final video signal. Therefore,
It is necessary to shift the timing of the signals of the two groups.

If the timings of the above components of the input signal are originally different or overlapped, the switches 765, 765a, 76 are used for temporal separation.
It is necessary to provide a memory in 5b and 765c to store the data and adjust the time axis. However, the transmission signal of the transmitter is shown in FIG.
By separately transmitting the timing 1 and the timing 2 as described above, the time axis adjustment circuit is not required on the receiver side. Therefore, there is an effect that the structure of the receiver is simplified.

[0267] D1 time layout of FIG. 73 shows a first data stream D1 of the transmission signal, H _L V _L by the D-channel for the duration of the timing _{1, H L V H, H} H V L, H H V Send an _H signal,
H _L V _H -H at D2 channel during the timing 2, H
_H V _L -H, shows the time arrangement of signals when sending the _{H H} V _H -H. By thus transmitting the transmission signals separated in time, there is an effect that the circuit configuration of the receiver econcoder is deleted.

Next, the number of extension parts of the receiver is large. A method of reducing these numbers will be described. FIG. 74 (b) shows a time allocation diagram of transmission signal data 810, 810a, 810b, 810c. In this figure, separate data 811, 810a, 811b, 811c are transmitted between the data.
Then, the target transmission data is intermittently transmitted. Then, the second image encoder 422 shown in the block diagram of FIG.
21 and the switch 812 to successively input the data to the decompression unit 503. For example, after the input of the data 810 is completed, the expansion processing is performed during the time of the different data 811, and after the processing of the data 810 is completed, the next data 810a is input. By doing so, it is possible to share one decompressing unit 503 in a time-division manner by the same method as in the case of the combiner. In this way, the total number of extension parts can be reduced.

FIG. 75 is a time allocation diagram when transmitting HDTV. For example, NTS of the first channel of the broadcast program
If the H _L V _L signal corresponding to the C component is H _L V _L (1),
This is arranged in time at the position of the data 821 indicated by the thick line of the D1 signal. The H _L V _H , H _H V _L , and H _H V _H signals corresponding to the HDTV additional component of the first channel are the data 82 of the D2 signal.
It is arranged at the positions of 1a, 821b, and 821c. Then, another data 822, 822a, 822b, 822 which is information of another TV program is provided between all the data of the first channel.
Since c exists, the expansion processing of the expansion unit is possible during this period. Thus, one extension can process all components. This method can be applied when the processing of the expander is fast.

Similar effects can be obtained by arranging data 821, 821a, 821b, 821c in the D1 signal as shown in FIG. This is effective when transmitting and receiving by using transmission without a hierarchy such as normal 4PSK and 4ASK.

FIG. 77 shows, for example, NTSC and HDTV and high resolution HDTV or low resolution NTSC and NTSC.
And a time allocation diagram in the case of performing hierarchical multilevel broadcasting of a three-layer video such as HDTV by physically using a two-layer hierarchical transmission system. For example, low resolution NTSC, NTSC and HD
When broadcasting 3 layers of TV image, low resolution N for D1 signal
H _L V _L signal corresponding to the TSC signal is placed in the data 821. Further, the separation signal NTSC _{H L} V H, H
_H V _{L, H} H V signals of each component of _H data 821a, 821
b, 821c. HDTV is a separation signal _{H L V H -H, H H} V L -H, H H V H -H signal are arranged data 823,823A, to 823b.

Here, as shown in the block diagrams of FIG. 156 and FIG. 170, logical hierarchical transmission by differentiating the error correction capability described in the second embodiment is added to 4VSB, 8VSB and 16VSB. Specifically, H _L D _L uses the D _1-1 channel in the D ₁ signal. As described in the second embodiment, the D _1-1 channel employs an error correction method having a much higher correction capability than the D _1-2 channel. D _1-1
The channel has higher redundancy than the D _1-2 channel, but the error rate after reproduction is low, so other data 821
It can be reproduced even under the condition that the C / N value is lower than a, 821b and 821c. Therefore, even in a case where the receiving condition is bad such as a region far from the antenna or the inside of a car, the program can be reproduced with the quality of the low resolution NTSC TV. In terms of the error rate as described in the second embodiment,
The data 821 on the D _1-1 channel in the D ₁ signal is the other data 821a and 821 on the D _1-2 channel.
b, 821c, more resistant to reception interference, differentiated, and different in logical hierarchy. As described in the second embodiment, D ₁ ,
The layer of D ₂ can be said to be a physical layer, and the layered structure obtained by differentiating the distance between error correction codes can be said to be a logical layered structure.

Now, demodulation of the D ₂ signal physically requires a C / N value higher than that of the D ₁ signal. Therefore, C in remote areas
/ The lowest reception condition of N values, i.e. H _L V _L signal, the low resolution NTSC signal is reproduced. Then, under the receiving condition of the next lowest C / N value, H _L V _H , H _H V _L , and H _H V _H are reproduced, and the NTSC signal can be reproduced. In addition to the H _L V _L is high reception conditions of C / N values _{H L V H -H, H H} V L
-H, HDTV signals for also played _H H V _H -H is played. In this way, broadcasting of three layers can be performed. By using this method, the receivable area described with reference to FIG. 53 is expanded from two layers to three layers as shown in the reception interference area diagram of FIG. 90, and the program receivable area is further expanded.

FIG. 78 shows a block diagram of the third image decoder in the case of the time arrangement shown in FIG. Basically Fig. 7
The block diagram of FIG. 2 has a configuration in which the third input unit 551 of the D3 signal is omitted and the configuration of the block diagram of FIG.

The operation will be described. At timing 1, the D1 signal is input from the input section 521 and the D2 signal is input from the input section 530. Since each component such as H _L V _H is temporally separated, these are sequentially and independently sent to the decompression unit 503 by the switch 812. This order will be described with reference to the time allocation diagram of FIG. First, the H _L V _L compressed signal of the first channel enters the decompression unit 503 and undergoes decompression processing. Next, H _L V _H , H _H V _L , and H _H V _{H of} the first channel are expanded, input to a predetermined input section of the combiner 556 through the switch 812a, and combined, and first, H _L The _VL- H signals are combined. This signal is input from the output 1 of the switch 765 a to the input 2 of the switch 765, and is input to the H _L V _L input section of the combiner 556.

Next, at the timing 2, as shown in the time arrangement diagram of FIG. 77, H _L V _H −H and H _H V _L − of the D2 signal.
_H, H H V H -H signal is inputted is extended by extension 503, the signal through the switch 812a is combiner 556
Is input to a predetermined input of, and a composite processing is performed to output an HDTV signal. The HDTV signal is output from the output 2 of the switch 765a via the output unit 521. As described above, transmitting by the time arrangement of FIG. 77 has the effect of significantly reducing the number of expanders and combiners of the receiver. Note that FIG. 77 shows D1 in the time allocation diagram.
Although the two stages of the D2 signal are used, when the above-mentioned D3 signal is used, a high-definition HDTV can be added to perform TV broadcasting of four layers.

[0277] Fig. 79 is a time allocation diagram of hierarchical broadcasting for broadcasting video of three layers using the three physical layers D1, D2 and D3. As is clear from the figure, the components of the same TV channel are arranged so as not to overlap in time.
Further, FIG. 80 shows a receiver obtained by adding a third input unit 521a to the receiver described in the block diagram of FIG. Broadcasting by the time arrangement of FIG. 79 has an effect that the receiver can be configured with a simple configuration as shown in the block diagram of FIG.

The operation is almost the same as the time allocation diagram of FIG. 77 and the block diagram of FIG. Therefore, the description is omitted.
Further, all signals can be time-multiplexed with the D1 signal as shown in the time allocation diagram of FIG. In this case, the data 821
And the separate data 822 are two data 821a, 821
12b and 821c have higher error correction capability. Therefore, the hierarchy is higher than other data. As mentioned above, it is physically one layer but logically two.
It is a hierarchical transmission of layers. Further, another data of another program channel 2 is bundled between the data of the program channel 1. Therefore, serial processing can be performed on the receiver side, and the same effect as the time allocation diagram of FIG. 79 can be obtained.

In the case of the time allocation diagram of FIG. 81, a logical hierarchy is used. Since the error rate of is reduced, it is possible to perform physical layer transmission. In this case, there are three physical layers.

FIG. 82 is similar to the time allocation diagram of FIG.
Image decoder 4 for transmitting only data string D1 signal
The block diagram of 23 has a simpler configuration than the image decoder shown in the block diagram of FIG. 80. The operation is shown in Figure 80.
The description is omitted because it is the same as the image decoder described in.

As described above, transmitting a transmission signal as shown in the time allocation diagram of FIG. 81 has the effect of significantly reducing the number of decompression unit 503 combiners 556 as shown in the block diagram of FIG. Since the four components are temporally separated and input, the combiner 556, that is, the image combiner 5 in FIG.
It is also possible to share some of the blocks in time division by omitting the circuit by changing the connection in accordance with the image components that input the circuit blocks inside 48.

As described above, there is an effect that the receiver can be configured with a simple configuration. In the fifth embodiment, AS
Although the operation has been described using K modulation, many of the techniques described in the fifth embodiment are PSK and QA described in the first, second, and third embodiments.
It can also be used for M modulation.

The above-described embodiments can also be used for FSK modulation. For example, as shown in FIG. 83, f1, f2, f3, f4
When multi-level FSK modulation is performed, grouping is performed as shown in the signal point arrangement diagram of FIG. 58 of the fifth embodiment, and the signal point positions of each group are separated so that hierarchical transmission can be performed.

In FIG. 83, the frequency group 841 of frequencies f1 and f2 is defined as D1 = 0, and the frequency group 842 of frequencies f3 and f4 is defined as D1 = 1. And f1, f3
If D2 = 0, f2, and f4 are defined as D2 = 1, as shown in the figure, 1-bit each of D1 and D2, a total of 2-bit hierarchical transmission becomes possible. For example, when C / N is high, t = t
At 3, D1 = 0 and D2 = 1 can be reproduced, and at t = t4, D1 = 1 and D2 = 0 can be reproduced. Next, when C / N is low, only D1 = 0 can be reproduced at t = t3, and only D = 1 can be reproduced at t = t4. In this way, FSK hierarchical transmission can be performed. It is also possible to use the FSK hierarchical multilevel transmission system for the hierarchical broadcasting of the video signal described in the third, fourth and fifth embodiments.

Further, the fifth embodiment of the present invention can be applied to the magnetic recording / reproducing apparatus shown in the block diagram of FIG. Since the fifth embodiment is ASK, magnetic recording and reproduction can be performed.

FIG. 84 shows a recording device (Recorder) / transmitter (Transmitter) and a reproducing device (Play).
er) / receiver (Receiver) block diagram.

In the block diagram of FIG. 84, the transmitter 1,
According to the VSB-ASK modulation method of the fifth embodiment of the receiver 43, the transmitter circuit 5a of the transmitter 1 is connected to the recording device magnetic recording signal amplifier 85.
7a, and the reception circuit 24a of the receiver 43 is replaced with the magnetic reproduction signal amplifier 857b, so that the same configuration is obtained. In the present text, all ASK signals in the transmission apparatus are VSB-ASK, so the VSB-ASK signal will be abbreviated as the ASK signal in the description.

The operation of FIG. 84 will be described. The HDTV signal is compressed by the video encoder 401 and then 2
The first data string is error coded by the ECC encoder 743a, and the second data string is ECC7.
Trellis Enc after error coding at 44a
Trellis encoded by oder 744b to produce VS
Enter B-ASK Modulator 749. Rec
Offset Generator8 for oder
The recording circuit 8 after adding an Offset signal by 56
It is recorded on the magnetic tape 855 by 53. Offset for Transmitter 1 of the transmission device
The DC offset voltage is superimposed on the ASK signal by the Generator 856, and the up converter 5a
Sent by. By performing the DC offset, it becomes easy for the receiver 43 to reproduce the carrier. The transmitted VSB-ASK signals of 4VSB, 8VSB and 16VSB are received by the antenna 32b and input to the demodulator 852a via the receiving circuit 24a.

On the other hand, the recording signal recorded by the recording device is reproduced by the reproducing head 854a and is also sent to the demodulator 852b via the reproducing circuit 858.

The signal input to the demodulator 852b passes through the filter 858a of the demodulator 852b and is demodulated by the above-mentioned ASK demodulator 852b such as VSB. The first data string of the demodulated signal is error-corrected by the ECC decoder 758a, and the second data string is Trellis decoder 75.
9b and the ECC decoder 759a perform error correction. Then, the video decoder 402 expands the video signal and outputs an HDTV, TV signal or SDTV signal.

Although the circuit is complicated by the addition of the Trellis encoder, the error rate is reduced, the transmission distance of the transmission device is extended, and the image quality of the recording / reproducing device is improved. In this case, the Filter 858a of the receiver 43 is shown in FIG.
By using the comb-shaped Filter 760a having a filter characteristic for eliminating the main carrier, video carrier, and audio carrier of the analog TV signal as shown in FIG. 4, it is possible to eliminate the interference of the analog TV signal and reduce the error rate. . In this case, if the filter is always inserted even when there is no interference, the received signal deteriorates. To avoid this, as shown in FIG. 65, the error rate detection unit 782 turns on the analog TV filter 760a only when the signal is deteriorated due to the interference of the analog TV and turns it off when there is no interference. It is possible to prevent signal deterioration due to.

In the case of FIG. 84, the error rate is smaller in the second data string after the first data string and the second data string. Therefore, by transmitting / recording important High priority (HP) information such as the descramble information of FIG. 66 and the header information of the image data of each image block in the second data string, the descramble and each image can be The image signal reproduction of the block can be stabilized.

Further, as shown in FIGS. 137 and 172, 8 V
In a transmission device of SB or 16VSB, a code string for error correction of a trellis decoder or an ECC decoder is changed for each sub-channel of a time-divided data string of each sub-channel, and High Priority (HP) information is assigned to a higher one. Send on a subchannel of. Since the error rate of the HP information is low, noise is generated to some extent on the transmission line and the signal deteriorates, causing the LowPri.
Even if the ority information (LP) information is destroyed, the HP information data is not destroyed. By transmitting the above-mentioned descrambling information or header information such as the address of the data packet in image block units as the HP information, the descrambling is stable for a long time, and the viewer can stably watch the descrambled program. In addition, since each image block is prevented from being destroyed catastrophically, even if the received signal is deteriorated, the entire image quality is deteriorated, so that the viewer can watch the TV program with a certain image quality.

(Embodiment 6) An example in which the transmission recording method of the present invention is applied to a magnetic recording / reproducing apparatus according to a sixth embodiment will be described. In the fifth embodiment, the case where the present invention is applied to the multi-level ASK transmission system is shown, but the present invention is also applied to the multi-level ASK recording system magnetic recording / reproducing apparatus as shown in the block diagram of FIG. Can be applied. In addition to ASK,
By applying the C-CDM system of the present invention to PSK, FCK, and QAM, hierarchical and non-hierarchical multilevel magnetic recording is possible. As described above, the present invention can be applied to both a recording device and a transmission device, but an example of the recording device will be described.

First, a method of hierarchization and multi-leveling will be described using an example in which the C-CDM system of the present invention is applied to a 16QAM or 32QAM magnetic recording / reproducing apparatus. FIG. 84 describes the transmission / recording apparatus using 9ASK such as multi-valued VSB in the fifth embodiment, but the same effect can be obtained even if ASK in FIG. 84 is changed to QAM. 84 and 173, Q
A case where C-CDM is applied to AM will be described. Below QA
C-CDM multiplexed M is called SRQAM. Note that FIGS. 137 and 154 describe a case where the present invention is applied to a transmission system.

Referring to FIGS. 84 and 173, the magnetic recording / reproducing apparatus 851 uses the first image encoder 401a and the second image encoder 401b of the image encoder 401 to input the inputted video signal of the HDTV or the like into the high frequency signal and the low frequency signal. The first data string input unit 743 of the input unit 742 is compressed to a low-frequency video signal such as an H _L V _L component, and the second data string input unit 744 includes a H _H V V _H component or the like. The local video signal is input to the modulator 749 in the modulator / demodulator 852.
In the first data string input unit 743, the error correction code is E
It is added to the low frequency signal in the CC unit 73a. On the other hand, the second data string input to the second data string input unit 744 is 1
In the case of 6SRQAM, 36SRQAM, and 64SRQAM, it becomes 2 bits, 3 bits, and 4 bits. This signal is error coded by the ECC 744a and then 16SRQAM, 32SRQ by the Trellis encoder 744b.
In the case of AM and 64SRQAM, FIG. 128 (a) (b)
1 each by Trellis Encoder 744b shown in (c)
It is Trellis coded with a ratio of / 2, 2/3, 3/4.
For example, in the case of 64 SRQAM, the first data string is 2 bits
Then, the second data string becomes 4 bits. Therefore, FIG.
Using Trellis Encoder 744b as shown in (c), 3
Trellis E of Ratio 3/4 with 4 bit data
do ncode. In the case of 4ASK, 8ASK, and 16ASK, 1/2, 2/3, and 3/4 trellis encoding is independently performed. In this way, the redundancy is increased and the data rate is decreased while the error correction capability is increased, so that the error rate of the same data rate can be decreased. Therefore, the amount of information transmission of the recording / reproducing system or the transmission system is substantially increased. In the case of the 8VSB transmission system described in the fifth embodiment, since it is 3 bits / symbol, FIG.
(B) Trellis Encode of Ratio2 / 3 shown in (e)
r744g and Trellis Decoder 744q can be used, and the overall block diagram is as shown in FIG. However, Trellis
In the block diagram of FIG. 84 of the sixth embodiment, Encode is not used for the first data string which originally has a low error rate because the circuit becomes complicated. Although the second data string has a smaller inter-code distance and a lower error rate than the first data string, the error rate is improved by Trellis-encoding the second data string. The configuration in which the Trellis encoding circuit for the first data string is omitted has the effect of making the entire circuit simpler. Since the modulation operation is almost the same as that of the transmitter of FIG. 64 of the fifth embodiment, detailed description will be omitted. In the recording / reproducing circuit 853, the signal modulated by the modulator 749 is AC biased by the bias generator 856, widened by the widening device 857 a, and recorded on the magnetic tape 855 by the magnetic head 854.

[0297] with information is recorded in the main signal 859 for example 16SRQAM of having a frequency fc becomes the carrier as shown in a recording signal frequency arrangement diagram of a format of the recording signal Figure 113, the frequency of 2 times the 2f _c in f _c A pilot f _p signal 859a with is recorded simultaneously. Frequency f
_The bias signal 859b of _BIAS applies AC bias to the magnetic recording, so that the distortion during recording is reduced. Since the multi-level recording of two layers among the three layers shown in FIG. 113 is performed, the thresholds for recording / reproducing are Th-1-2 and Th-.
There are two of two. Depending on the C / N level of recording / reproducing, if the signal 859 is two layers, and if the signal is 859C, only D ₁ is recorded / reproducing.

When 16 SRQAM is used for the main signal, the signal point arrangement is as shown in FIG. When 36 SRQAM is used, the result is as shown in FIG. 4ASK, 8ASK
In the case of using, the arrangement is as shown in FIGS. 58, 68 (a) and 68 (b). When reproducing this signal, the magnetic head 854
From, the main signal 859 and the pilot signal 859a are reproduced and amplified by the amplifier 857b. From this signal, a filter 858a of the carrier recovery circuit 858 outputs 2f _o.
The frequency of the pilot signal f _p is separated, the carrier of f _o is regenerated by the 1/2 frequency divider 858b, and the demodulation unit 760
Sent to. The demodulation unit 76 uses the reproduced carrier wave.
At 0, the main signal is demodulated. At this time, if a magnetic recording tape 855 having a high C / N value such as for HDTV is used, it becomes easy to discriminate each of the 16 signal points, and therefore the demodulation unit 7
At 60, both D1 and D2 are demodulated. Then, the image decoder 422 reproduces all signals. HDTV
In the case of VTR, for example, a high bit rate TV signal of HDTV of 15 Mbps is reproduced. The lower the C / N value, the lower the cost. At present, there is a difference of 10 dB or more in C / N between the commercially available VHS tape and the high C / N type tape for broadcasting. When an inexpensive video tape 855 having a low C / N value is used, it is difficult to discriminate all 16-value and 36-value signal points because the C / N value is low. Therefore, the first data string D1 can be reproduced, but the 2-bit, 3-bit, or 4-bit data string of the second data string D2 cannot be reproduced, and only the 2-bit data string of the first data string is reproduced. When a two-layer hierarchical HDTV image signal is recorded / reproduced, the low-frequency C / N tape does not reproduce the high-frequency image signal. An NTSC TV signal is output.

Further, as shown in the block diagram of FIG. 114, the second data string output unit 759, the second data string input unit 744 and the second image decoder 422a are omitted, and the first data string D ₁
A recording / reproducing device 851 dedicated to a low bit rate having a modulator such as a modified QPSK that modulates / demodulates only the signal can be set as one product form. This device can record and reproduce only the first data string. That is, a wide NTSC grade image signal can be recorded and reproduced. When the video tape 855, which outputs a high C / N value in which a high bit rate signal such as the above HDTV signal is recorded, is reproduced by the magnetic recording / reproducing apparatus dedicated to the low bit rate, only the D1 signal of the first data string is generated. Is reproduced, the wide NTSC signal is output, and the second data string is not reproduced. That is, when the video tape 855 on which the HDTV signal of the same layer type is recorded is reproduced, the HDTV signal can be reproduced by the recording / reproducing apparatus having one complicated structure and the wide NTSCTV signal can be reproduced by the recording / reproducing apparatus having the one simple structure. That is, in the case of two layers, there is a great effect that full compatibility of four combinations is realized between tapes having different C / N values and models having different recording / reproducing data rates. In this case, NT
The SC dedicated machine has a remarkably simple structure. Specifically, for example, the circuit scale of the EDTV decoder is 1/6 that of the HDTV decoder. Therefore, a low-function machine can be realized at a significantly low cost. As described above, since two types of recording / reproducing devices having different recording and reproducing capacities of HDTV and EDTV can be realized, it is possible to set a wide range of price models. Also, the user can freely select a tape from a high-priced tape with a high C / N to a low-priced tape with a low C / N according to the required image quality. In this way, it is possible to obtain expandability while maintaining complete compatibility, and to ensure compatibility with the future. Therefore, it becomes possible to realize a standard of a recording / reproducing apparatus that will not be obsolete in the future. As another recording method, hierarchical recording by the phase modulation described in the first and third embodiments can be performed.

Recording by ASK described in the fifth embodiment is also possible. 59 (c) and (d) in FIG.
As shown in FIGS. 68 (a) and 68 (b), signal points of 4-valued ASK and 8-valued ASK can be divided into two groups, and can be hierarchized into two layers and three layers.

The block diagram for ASK is the same as FIG. It becomes like FIG. Trellis and AS
The error rate decreases depending on the combination of K. In addition to the description in the embodiment, multi-level recording such as hierarchical recording by multi-tracks on a magnetic tape is also possible. Also, by changing the error correction ability,
A logical hierarchical record can be made by differentiating the data.

Here, compatibility with future standards will be described. Normally, when setting the standard of a recording / reproducing apparatus such as a VTR, the standard is determined by using the highest C / N tape that is actually available. The recording characteristics of the tape improve day by day. For example, the C / N value is currently improved by 10 dB or more as compared with the tape 10 years ago. In this case, 10 from the present
When a new standard is set when the tape performance is improved in the future 20 to 20 years later, it is very difficult for the conventional method to be compatible with the old standard. For this reason, the old and new standards were often one-sided or incompatible.

However, in the case of the present invention, first, a standard for recording / reproducing the first data string or the second data string on the current tape is created. Next, when the present invention is adopted in advance when the C / N of the tape is greatly improved in the future, the data of the upper data layer, for example, the data of the third data row is added, and the data of, for example, 3 is added.
Super HDTV VTR that records / reproduces 64 levels of SRQAM and 8ASK will be realized while maintaining full compatibility with conventional standards. At the time when this future standard was realized, the magnetic tape in which three layers were recorded up to the third data string according to the present invention and the new standard can record and reproduce only the first data string and the second data string. When reproduced by the reproducing apparatus, the third data string cannot be reproduced, but the first and second data strings can be completely reproduced. Therefore, the HDTV signal is reproduced. Therefore, there is an effect that the recording data amount can be expanded in the future while maintaining compatibility between the old and new standards.

Now, let us return to the description of the reproducing operation in FIG. When reproducing, the magnetic tape 855 is reproduced by the magnetic head 854 and the magnetic reproducing circuit 853 to reproduce the reproduced signal, and the modulator / demodulator 852 is reproduced.
Send to. Since the demodulation unit operates almost in the same way as in the first, third, and fourth embodiments, its explanation is omitted. The demodulation unit 760 reproduces the first data string D1 and the second data string D2, and the second data string is
By Trellis-Decoder 759b such as Vitabi decoder, c
High ode gain error correction, lower error rate. The D1 and D2 signals are demodulated by the image decoder 422 and an HDTV video signal is output.

The above is the embodiment of the magnetic recording / reproducing apparatus having two layers. Next, the embodiment of the magnetic recording / reproducing apparatus of three layers, which is one physical layer of two layers and one logical layer is added. This will be described with reference to the block diagram of FIG. 131. Basically, the configuration is the same as that of FIG. 84, but the first data string is
Furthermore, it is divided into two sub-channels to form a three-layer structure. As shown in FIG. 131, first, the HDTV signal is the first-1 image encoder 4 in the first image encoder 401a.
The 01c and the 1-2 image encoder 401d, 2 pieces of data midrange and low frequency video signal, D _1-1 and D1 _- are input to the first data stream input unit 2 to be separated input unit 742.
The data stream D _1-1 of MPEG grade image quality is ECC coder 7
Is the high error correction coding of Code gain at 43a, D1 _- 2 normal Code gai in ECC Coder743b
It is error correction coded with n. D _1-1 and D1 _- 2 is TD
One data string D is time-multiplexed by the M unit 743c.
Becomes ₁ . D ₁ and D 2 are modulated by the C-CDM modulator 749, and are hierarchically recorded in two layers on the magnetic tape 855 by the magnetic head 854.

At the time of reproduction, the recording signal reproduced by the magnetic head 854 is demodulated to D ₁ and D 2 by the C-CDM demodulation section 760 by the same operation as described with reference to FIG. The first data string D ₁ is transmitted to the two sub-channels D in the TDM unit 758c in the first data output unit 758.
_1-1 and D1 _- 2 is demodulated into. D _1-1 is an ECC with high code gain
In Decoder758a, to be error-corrected, D1 _- 2
D _1-1 is demodulated even at a lower C / N value than 1-1.
LDTV is decoded and output by the image decoder 402a. Meanwhile D1 _- 2 normal ECC Decoder7 of Code gain
Since the error correction at 58b, D1 _- signal level due to its threshold value of 1 in comparison the high C / N can not be played not larger. Then, demodulated in the 1-2 image encoder 402d, is combined with D _1-1, EDTV wide NTSC grade is outputted.

The second data string D2 is Trellis Decoder 759.
b by a Vitabi decoded, error corrected by ECC759a, the second image encoder 402b becomes a high-frequency image signal, D _1-1, D1 _- are 2 Synthesis HDTV it is outputted. The threshold of the C / N of D ₂ in the case D1 _- greater than 2 sets. Thus if C / N value of the tape 855 is small, D _1-1 clogging LDTV is reproduced, if the normal C / N value of the tape 855 D _1-1, D1 _- 2 clogging EDTV is reproduced, C / N having a high tape 855 its value when D _1-1, D1 _- 2, D2, that the HDTV signal is reproduced.

In this way, a magnetic recording / reproducing apparatus having three layers is realized. As described above, the C / N value of the tape 855 and the cost have a correlation. In the case of the present invention, the user can record and reproduce image signals of three grades of image quality corresponding to the cost of the three types of tapes, so that the user wants to record TV.
This has the effect of expanding the range of choices for tape grades depending on the content of the program.

Next, as shown in the recording track diagram of FIG. 132, which describes the effect of the hierarchical recording during fast-forward reproduction, the magnetic tape 8 is used.
On the 55, a recording track 855b having an azimuth angle A and a recording track 855b having an azimuth angle B opposite to the recording track 855a are recorded. The left recording area 855c in the center of the recording track 855a as shown is provided, the other region and D _1-2 recording region 855D. This is provided at least at one place for each of several recording tracks. One frame of LDTV is recorded in this. The D2 signal of the high frequency signal is recorded in the D2 recording area 855e of the entire area of the recording track 855a. This recording format has no new effect when recording / reproducing at a normal speed. Now, during fast-forward reproduction of the tape in the forward and reverse directions, the magnetic head trace 855f with the azimuth angle A does not coincide with the magnetic track as shown in the figure. In the present invention shown in FIG. 132, a D _1-1 recording area 855c set in a narrow area in the central portion of the tape is provided. Therefore, with a certain probability, this area is certainly reproduced. MPE from the reproduced D _1-1 signal
Although the image quality of LDTV is similar to that of G1, it is possible to demodulate the image of the entire screen at the same time. Thus, during fast-forward reproduction, if several to several tens of complete images of the LDTV are reproduced per second, the user can confirm the image screen during fast-forward, which is a great effect.

[0310] Also, at the time of reverse reproduction, the head trace 85
Only a partial area of the magnetic track is traced as shown in g. However, even in this case, when the recording / reproducing format shown in FIG. 132 is used, since the D1-1 recording area can be reproduced, a moving image of LDTV grade image quality is intermittently output.

As described above, according to the present invention, since an LDTV grade image is recorded in a narrow area of a part of the recording track, the user can intermittently obtain a substantially complete still image with the LDTV grade image quality when fast-forwarding in both forward and reverse directions. Since it can be played back, there is an effect that it is easy to check the screen during high-speed search.

Next, a method for coping with higher speed fast forward reproduction will be described. As shown in the lower right part of FIG. 132, a D _1-1 recording area 855C is provided to record one frame of the LDTV and D _1-1 / D ₂ recording of a narrower area in a part of the D _1-1 recording area 855C. A region 855h is provided. Some of the information in one frame of LDTV is recorded in the subchannel D _1-1 in this region. D ₂ recording region 855j of the remaining information of ldtv D _1-1 · D ₂ recording region 855h
Record in duplicate. The sub-channel D ₂ has a data recording amount 3 to 5 times that of the sub-channel D _1-1 . Therefore D
LDTV on tape of 1/3 to 1/5 area with _1-1 and D ₂
The information of one frame can be recorded. Since the head race can be recorded in the regions 855h and 855j, which are narrower, the time and area are 1/3 to 1/5 of the head trace time T _s1 . Therefore, even if the rapid traverse speed is increased and the head tracing is further inclined, the probability of tracing the entire area is increased. Therefore, a complete LDTV image is intermittently reproduced even during fast-forwarding which is 3 to 5 times faster than in the case of only D _1-1 .

In the case of a two-layer VTR, this system does not have the function of reproducing the D ₂ recording area 855j, so that it cannot be reproduced during fast forward. On the other hand, in the three-layer high-performance VTR, the image can be confirmed even when fast-forwarding 3 to 5 times faster than the two-layer. That is, not only the image quality according to the number of layers, that is, the cost, but also the VTR at which the reproducible maximum fast-forward speed differs according to the cost is realized.

Although the hierarchical modulation system is used in the embodiment, the fast-forward reproduction according to the present invention can be realized by performing the hierarchical image coding even with the normal modulation system such as 16QAM. Needless to say.

In the conventional non-hierarchical digital VTR recording method of highly compressing images, the image data is evenly distributed, and therefore all the images on the screen at the same time of each frame are reproduced at the time of fast-forward reproduction. You cannot do it. For this reason, only the images of which the time axis of each block on the screen is deviated can be reproduced. However, although the hierarchical HDTV VTR of the present invention is of LDTV grade, it has an effect of being able to reproduce an image in which the time axis of each block of the screen is not deviated during fast forward reproduction.

When three-layered recording of the HDTV of the present invention is performed, a high-resolution TV signal such as HDTV can be reproduced when the C / N of the recording / reproducing system is high. And the recording / playback system C /
When N is low or when reproduced by a magnetic reproducing device having a low function, an EDTV grade TV signal such as wide NTSC or an LDTV grade TV signal such as low resolution NTSC is output.

As described above, in the magnetic reproducing apparatus using the present invention, even when the C / N becomes low or the error rate becomes high, the same content image is reproduced at a low resolution or a low image quality. The effect of being able to be obtained is obtained.

(Embodiment 7) Embodiment 7 is a case where the present invention is applied to video hierarchy transmission of four layers. By combining the four-layer transmission method and the four-layer video data structure described in the second embodiment, as shown in the reception interference area diagram of FIG.
The reception area of the layer is created. As shown in the figure, a first reception area 890a is formed on the innermost side, and a second reception area 890b, a third reception area 890c, and a fourth reception area 890d are formed on the outer side.
A method for realizing these four layers will be described.

To realize four layers, there are four physical layers by modulation and four logical layers by differentiating the error correction capability, but the former has a large C / N difference between layers and is large in four layers. C / N is required. The latter is based on the premise that demodulation is possible, so that the C / N difference between layers cannot be made large. What is realistic is to perform 4-layer hierarchical transmission using a 2-layer physical layer and a 2-layer logical layer. Then
First, a method of separating a video signal into four layers will be described.

FIG. 93 is a block diagram of the separation circuit 3. The separation circuit 3 comprises a video separation circuit 895 and four compression circuits. The basic configuration inside the separation circuits 404a, 404b, and 404c is the first image encoder 40 in FIG.
Since it is the same as the block diagram of the separation circuit 404 in No. 1, description will be omitted. The separation circuit 404a or the like divides the video signal into a low frequency component H _{L VL} , a high frequency component H _H V _H, and intermediate components H _{H VL} and H _L V _H.
Separate into two signals. In this case, H _L V _L has half the resolution of the original video signal.

Now, the input video signal is the video separation circuit 40.
It is divided into two by 4a into a high frequency component and a low frequency component. Since it is divided in the horizontal and vertical directions, four components are output. The dividing points of the high band and the low band are at the midpoints in this embodiment. Therefore, if the input signal is a vertical 1000 HDTV signal, H
_{The L VL} signal is a TV signal with 500 vertical lines and half the horizontal resolution.

The low-frequency component H _L V _L signal is separated by the separation circuit 404c.
Thus, the frequency components in the horizontal and vertical directions are each further divided into two. Therefore, the H _L V _L output is, for example, 250 vertical lines and the horizontal resolution is 1/4. When this is defined as the LL signal, the LL component is compressed by the compression unit 405a and output as the _D1-1 signal.

On the other hand, the three components of the high frequency component of H _{L VL} are combined into one LH signal by the combiner 772c, and the compression unit 40
It is compressed by 5b and output as a D _1-2 signal. In this case, three compression units may be provided between the separation circuit 404c and the combiner 772c.

The three components of H _H V _H , H _L V _H and H _H V _L of the high frequency components are combined into one H _H V _H -H signal by the combiner 772a. When the compressed signal has 1000 vertical and horizontal signals, this signal has components of 500 to 1000 in the horizontal and vertical directions. Then, it is separated into four components by the separation circuit 404b.

Therefore, 500 to 750 components in the horizontal and vertical directions are separated as the H _L V _L output. This is called an HH signal. And the three components of H _H V _H , H _L V _H , and H _H V _L are 7
It has 50 to 1000 components, and is synthesized by the synthesizer 772b to be an HH signal, which is compressed by the compression unit 405d and is D
_2-2 Output as a signal. On the other hand, the HL signal is output as the D _2-1 signal. Therefore, LL, that is, the D _1-1 signal is, for example, 0 to 250 or less components, and LH, that is, the D _1-2 signal is 250 or more and 500 or less frequency components HL, that is, D.
_{The 2-1} signal has 500 or more and 750 or less components, and HH, that is, the D _2-2 signal has 750 or more and 1000 or less frequency components. This separating circuit 3 has an effect of forming a hierarchical data structure. By using the separation circuit 3 of FIG. 93 and replacing the part of the separation circuit 3 in the transmitter 1 of FIG. 87 described in the second embodiment, four-layer hierarchical transmission can be performed.

By combining the hierarchical data structure and the hierarchical transmission in this way, it is possible to realize image transmission in which the image quality gradually deteriorates as the C / N deteriorates. This has the great effect of expanding the service area in broadcasting.
Next, the receiver for demodulating and reproducing this signal has the same configuration and operation as the second receiver of FIG. 88 described in the second embodiment. Therefore, the whole operation is omitted. However, since the video signal is handled, the composition of the composition unit 37 is different from that of data transmission. Here, the combining unit 37
Will be described in detail.

As described with reference to the block diagram of the receiver of FIG. 88 in the second embodiment, the received signal is demodulated and error-corrected, and D _1-1 , D _1-2 , D _2-1 and D are received. _2-2 of 4
It becomes one signal and is input to the combining unit 37.

Here, FIG. 94 is a block diagram of the combining unit 33. The input D _1-1 , D _1-2 , D _2-1 and D _2-2 signals are expanded in the expansion units 523a, 523b, 523c and 523d, and LL and L described in the separation circuit of FIG.
It becomes H, HL, and HH signals. In this signal, LL is 1/4, L when the horizontal and vertical bands of the original video signal are 1.
L + LH is 1/2, LL + LH + HL is 3/4, LL +
LH + HL + HH is a band of 1. The LH signal is separated by the separator 531a, and is separated by L in the image combining unit 548a.
Is combined with the L signal is input to the H _L V _L terminal of the image synthesizing unit 548c. The description of the example of the image synthesizing unit 531a has been given with respect to the image decoder 527 of FIG.
On the other hand, the HH signal is separated by the separator 531b and input to the image synthesizing unit 548b. The HL signal is the image synthesizing unit 5
Is combined with HH signal at 48b, separated by the separator 531c becomes _H H V _H -H signal, the image combining unit 548
In c, it is combined with the combined signal of LH and LL to be a video signal, which is output from the combining unit 33. And second in FIG. 88.
The output unit 36 of the receiver outputs a TV signal. In this case, the original signal has 1050 vertical lines and approximately 1000 HDT lines.
If it is a V signal, TV signals of four image qualities are received under the four reception conditions shown in the reception interference diagram of FIG.

The image quality of the TV signal will be described in detail. FIG. 91
FIG. 86 is integrated into the transmission hierarchical structure diagram of FIG. In this way, the C / N is improved and the reception area 86 is increased.
D _1-1 in 2d, 862c, 862b, 862a,
D _1-2 , D _2-1 , and D _2-2, and the hierarchical channels that can be reproduced one after another are added to increase the data amount.

In the case of hierarchical transmission of video signals As shown in the transmission hierarchical structure diagram of FIG.
The hierarchical channels of the L and HH signals are reproduced. Therefore, the image quality improves as the distance from the transmitting antenna decreases. LL signal when L = Ld, L when L = Lc
L + LH signal, LL + LH + HL signal when L = Lb, L
= La, the LL + LH + HL + HH signal is reproduced.
Therefore, if the band of the original signal is 1, then 1/4, 1/2, 3
Image quality of / 4 and 1 bands is obtained in each reception area. If the original signal is an HDTV with 1000 vertical scanning lines, 250
Books, 500, 750, and 1000 TV signals can be obtained. In this way, hierarchical video transmission in which the image quality gradually deteriorates becomes possible. Figure 96 shows a conventional digital HDTV
It is a reception obstruction figure in the case of broadcasting. As is clear from the figure, in the conventional method, the reproduction of the TV signal becomes completely impossible when CN is V _O or less. Therefore, even within the service area distance R, reception cannot be performed as shown by a cross mark in a competitive area with other stations, a building shadow, or the like. FIG. 97 shows a receiving state diagram of HDTV hierarchical broadcasting using the present invention. As shown in FIG. 97, C / N = a at the distance La, C / N = b at the distance Lb, and C / N = at the distance Lc.
C / N = d in c and Ld, and 250 in each receiving area
Book, 500, 750, and 1000 image quality can be obtained. Even within the distance La, the C / N deteriorates, and there are areas where the image quality of HDTV cannot be reproduced. However, even in that case, it is possible to reproduce although the image quality is deteriorated. For example, 750 lines at the B point of the building shadow, 25 at the D point on the train
Image quality of 0, 750 at point F receiving ghost, 250 at point G in the car, and 250 at point L, which is a competitive area with other stations, can be reproduced. As described above, by using the hierarchical transmission of the present invention, it becomes possible to receive even in an area where reception and reproduction cannot be performed by the conventionally proposed method, and there is a remarkable effect that the service area of the TV station is greatly expanded. . Also, as shown in the hierarchical transmission diagram of FIG. 98, the program D of the same program as the analog broadcast in the area is broadcast on the D _1-1 channel, and the other channels are broadcast on the D _1-2 , D _2-1 and D _2-2 channels. By broadcasting the programs C, B, and A, the simulcast of the program D can be reliably broadcast in all regions, and the effect of multi-programming can be obtained by serving the other three programs while playing the role of the simulcast. To be

(Embodiment 8) A seventh embodiment will be described below with reference to the drawings. Embodiment 8 is an application of the hierarchical transmission system of the present invention to a transceiver of a cellular telephone system. In the block diagram of the transceiver of the mobile phone of FIG. 115, the voice of the caller input from the microphone 762 is the data D ₁ , D ₂ , D _{3 of} the hierarchical structure described above by the compression unit 405.
1 is compressed and encoded into a predetermined time slot based on the timing in the time division unit 765, and the modulator 4 receives hierarchical modulation such as SRQAM described above.
One carrier wave is transmitted from the antenna 22 via the antenna duplexer 764, is received by a base station described later, is transmitted to another base station or a telephone station, and can communicate with another telephone.

On the other hand, communication signals from other telephones are received by the antenna 22 as radio waves transmitted from the base station. The received signal is demodulated as data of D ₁ , D ₂ and D ₃ in a hierarchical demodulator 45 such as SRQAM. A timing circuit 767 detects a timing signal from the demodulated signal, and the timing signal is sent to the time division unit 765. The demodulated signals D ₁ , D ₂ , and D ₃ are expanded by the expansion unit 503 to become a voice signal, which is sent to the speaker 65 and becomes voice.

Next, as shown in the block diagram of the base station in FIG. 116, three hexagonal or circular reception cells 768, 7 are received.
69,770, base stations 771 and 77 at the center of each
2, 773 are transceivers 761a to 761 similar to those in FIG.
It has a plurality of 1j and transmits and receives data of the same number of channels as the number of transceivers. The base station control unit 774 connected to each base station constantly monitors the traffic volume of the communication of each base station, and accordingly allocates the channel frequency to each base station and the size of the reception cell of each base station. Control the entire system such as control.

As shown in the conventional method communication capacity traffic distribution chart of FIG. 117, in the conventional digital communication method such as QPSK, the transmission capacity of Ach of the receiving cells 768 and 770 is the same number of waves as shown in the figure of d = A. Usage efficiency 2bit /
The data 774d is a combination of the data 774d and 774b of Hz and the data 774c of the figure of d = B, and the frequency utilization efficiency is uniform at 2 bits / Hz at any point.
On the other hand, the actual urban areas are densely populated areas 775a, 775b, 77.
In areas where buildings are concentrated like 5c, the population density is high,
The amount of communication traffic also peaks as shown by the data 774e. The amount of communication is small in other surrounding areas.
With respect to the data 774e of the actual traffic volume TF, the capacity of the conventional cellular telephone has the same frequency efficiency of 2 bit / Hz in all regions as shown in the data 774d. In other words, there is an inefficiency that the same frequency efficiency is applied to a place with a small amount of traffic as well as a place with a large amount of traffic. In the conventional method, in a region with a large amount of traffic, the frequency allocation is increased to increase the number of channels, or the size of the receiving cell is reduced. However, there was a restriction on the frequency spectrum to increase the number of channels. In addition, multi-leveling such as 16QAM and 64QAM in the conventional method increased the transmission power. Reducing the size of the receiving cells and increasing the number of cells leads to an increase in the number of base stations and increases the installation cost. There are the above problems.

Ideally, increasing the frequency efficiency in an area with a large amount of traffic, increasing the frequency efficiency in an area with a small amount of traffic, and decreasing the frequency efficiency in an area with a small amount of traffic will increase the efficiency of the entire system. To be The above can be realized by adopting the hierarchical transmission system of the present invention. This will be described with reference to the communication capacity / traffic distribution chart in Embodiment 8 of the present invention in FIG. Figure 11
The distribution map of No. 8 is the receiving cells 770B, 768, 7 in order from the top.
The communication capacities on the AA 'line of 69, 770, and 770a are shown. The receiving cells 768 and 770 use the frequencies of the channel group A and the receiving cells 770b, 769 and 770a do not overlap with the channel group A. These channels are shown in FIG. 1 according to the traffic volume of each receiving cell.
The number of channels is increased or decreased by 16 base station controllers 774. In FIG. 118, d = A shows the distribution of the communication capacity of the A channel. d = B is the communication capacity of the B channel, d = A + B is the communication capacity of all channels added together, TF is the communication traffic volume, and P is the distribution of buildings and population. Since the receiving cells 768, 769, and 770 use the multilayer hierarchical transmission method such as SRQAM described in the previous embodiment, as shown in data 776a, 776b, and 776c, the frequency utilization efficiency of QPSK is 2 bits / Hz. The doubled 6 bit / Hz can be obtained in the periphery of the base station. It decreases to 4 bits / Hz and 2 bits / Hz as it goes to the periphery. If the transmission power is not increased, the dotted lines 777a, b,
2 bits compared to the size of the reception cell of QPSK shown in c.
Although the area of / Hz becomes narrower, an equivalent reception cell size can be obtained by slightly increasing the transmission power of the base station.
The 64SRQAM-compatible slave station transmits / receives with modified QPSK in which the shift amount of SRQAM is S = 1 at a place far from the base station, 16SRQAM at a near place, and 64SRQAM at a near place. Therefore, the maximum transmission power does not increase as compared with QPSK. In addition, 4SRQ as shown in the block diagram of FIG.
The AM transceiver can also communicate with other phones while maintaining compatibility. The same applies to the case of 16SRQAM shown in the block diagram of FIG. Therefore, there are three modulation type slaves. For mobile phones, small scale is important. 4 SRQ
In the case of AM, the frequency usage efficiency is lowered and the call charge is increased, but since the circuit is simple, it is suitable for users who are required to be small and lightweight. In this way, this method can be applied to a wide range of applications.

As described above, a transmission system having distributions with different capacities such as d = A + B in FIG. 118 can be obtained.
Installing a base station according to the amount of TF traffic has a great effect of improving the overall frequency utilization efficiency. In particular, in the microcell system having a small cell, since many sub base stations can be installed, it is easy to install the sub base station in a place with a lot of traffic, and the effect of the present invention is high.

Next, the data arrangement of each time slot will be described with reference to the data time arrangement diagram of FIG. FIG. 119
FIG. 119A shows a conventional time slot, and FIG. 119B shows a time slot of the eighth embodiment. As shown in FIG. 119 (a), the conventional transmission / reception frequency system transmits the synchronization signal S at the time slot 780a at frequency A at the time of transmission from the base station to the slave station, and the slot 780b,
At 780c and 780d, transmission signals to the slave units of A, B and C channels are sent. Next, when sending from the Up side, that is, from the child device to the base station, the time slots 781a and 781 at the frequency B are transmitted.
Sync signals are transmitted to b, 781c, and 781d, and a, b, and c channels are transmitted.

In the case of the present invention, as shown in FIG. 119 (b), since the hierarchical transmission system such as the above-mentioned 64SRQAM is used, three hierarchical data of 2 bits / Hz for each of D ₁ , D ₂ and D ₃ are used. With. Since A ₁ and A ₂ data are sent by 16SRQAM, slots 782b and 782c and slot 783
b, 783c, the data rate is about double. When sending with the same sound quality, it can be sent in half the time. Therefore, the time slots 782b and 782c are half the time.
Thus, double the transmission capacity is obtained in the area of the second layer of 776c in FIG. 118, that is, in the vicinity of the base station. Similarly,
In the time slots 782g and 783g, transmission / reception of E ₁ data is performed by 64 SRQAM. Because having a transmission capacity of about 3 times, E ₁ three times in the same time slot, E _2, E ₃
3 channels can be secured. In this case, transmission / reception is required in an area near the base station. In this way, there is an effect that a maximum of about three times as many calls can be obtained in the same frequency band. However, in this case, this is the case where the call is made as it is in the vicinity of the base station, which is actually lower than this number. In addition, the actual transmission efficiency drops to about 90%. In order to enhance the effect of the present invention, it is desirable that the regional distribution of traffic volume and the transmission capacity distribution according to the present invention match. But,
As shown in the TF diagram of FIG. 118, in an actual city, green zones are arranged around the building street. Even in the suburbs, fields and forests are arranged around the residential area. Therefore, the distribution is close to that of the TF diagram. Therefore, the effect of applying the present invention is high.

In the TDMA time slot diagram of FIG. 120, (a) shows the conventional method and (b) shows the method of the present invention. Figure 1
As shown in FIG. 20 (a), in the same frequency band, the time slots 786a and 786b transmit to the A and B channel slave units, respectively, and the time slots 787a and 787b transmit to the A and B channel slave units, respectively. I do. FIG. 120
As shown in (b), in the case of 16 SRQAM in the present invention, the A ₁ channel is received in the slot 788a, and the A ₁ channel is transmitted in the slot 788c. The time slot width is about 1/2. In the case of 64 SRQAM, D ₁ channel is received in slot 788i, and D ₁ channel is transmitted in slot 788l. The time slot width is about 1/3.

In particular, in order to reduce the power consumption, the slot 78
16 SRQAM with 1/2 time slot in 8p
E ₁ is received, but the transmission is performed in the normal time slot 4SRQAM in the slot 788r. 16 SRQAM
Since 4SRQAM consumes less power, it has the effect of reducing power consumption during transmission. However, the longer the occupation time, the higher the communication charge. It is highly effective for small and lightweight mobile phones with a small battery and when the battery level is low.

As described above, since the transmission capacity distribution can be set according to the actual traffic distribution, there is an effect that the substantial transmission capacity can be increased. In addition, the transmission capacity of three or two transmission capacities can be selected by the base station and the slave station, so that frequency efficiency can be reduced to reduce power consumption, and conversely, efficiency can be increased to reduce call charges, providing a high degree of freedom and various effects. Is obtained. Also, 4S RQA with low transmission capacity
By using the method such as M, it is possible to set a child device having a simple circuit and a small size and low cost. In this case, one of the features of the present invention is that the transmission compatibility between all the models can be obtained as described in the previous embodiment. In this way, with the increase in transmission capacity, it is possible to expand the range of models from ultra-compact to highly functional.

(Embodiment 9) A ninth embodiment will be described below with reference to the drawings. The ninth embodiment applies the present invention to an OFDM transmission system. The block diagram of the OFDM transmitter / receiver of FIG. 123 and the operation principle diagram of the OFDM of FIG. 124 are shown. F
OFDM, which is a type of DM, has a higher frequency band utilization efficiency than general FDM by making adjacent carriers orthogonal. It is also considered for digital music broadcasting and digital TV broadcasting because it is resistant to multipath interference such as ghost. As shown in the principle diagram of OFDM in FIG.
In the case of, the serial-parallel converter 791 converts the input signal into the frequency axis 79
Data are arranged on the No. 3 at an interval of 1 / ts to create subchannels 794a to 794e. Inverse FFT device 40
Inverse FFT conversion is performed on the time axis 799 by the modulator 4 having a transmission signal 795. This inverse FFTed signal is transmitted during a period of ts valid symbol periods 796, and a tg guard period 797 is provided between each symbol.

The operation of the ninth embodiment when transmitting and receiving HDTV signals will be described with reference to the block diagram of the OFDM-CCD M hybrid system of FIG. Input HDTV
The signal is separated by the image encoder 401 into an image signal having a three-layered hierarchical structure of low range D _1-1 , (middle range-low range) D _1-2, and (high range-middle range-low range) D ₂ . It is input to the input unit 742. In the first data string input section 743, the D _1-1 signal is C
ECC coding with high ode gain is performed, and the D _1-2 signal is encoded with normal code gain ECC. D _1-1 and D
_2-2 is time-division multiplexed by the TDM unit 743, and D ₁
Signal, and the D ₁ serial-parallel converter 79 of the modulator 852a
1a is input. The D ₁ signal becomes n pieces of parallel data and is input to the first input portions of the n pieces of C-CDM modulators 4a, 4b, ....

On the other hand, D ₂ of the high frequency component signal is input to the input section 742.
ECC unit 744a in second data string input unit 744 of
In ECC (Error Correction Code) and trellis coded in trellis encoder 744b, and is input to D ₂ series-parallel device 791b of modulator 852a to become n pieces of parallel data, and C-CDM modulator 4a,
4b ... is input to the second input unit. Each C-CDM is composed of D ₁ data of the first input section and D ₂ data of the second input section.
The modulators 4a, 4b, 4c ... Are C-CDM modulated to 16 SRQAM or the like. The n C-CDM modulators have carriers of different frequencies, and adjacent carriers are 794a, 794b and 794c in FIG.
As shown by ..., they are on the frequency axis 793 while being orthogonal to each other. Thus, the C-CDM modulated n modulation signals are mapped by the inverse FFT circuit 40 from the frequency axis dimension 793 to the time axis dimension 790,
The time signals 796a and 796b having an effective symbol length of ts are obtained. Between the effective symbol time zones 796a and 796b, a guard time zone 7 of Tg seconds is set in order to reduce multipath interference.
97a is provided. A time axis-signal level diagram of this is shown in the time axis-signal level diagram of FIG. 129. The Tg of the guard time zone 797a is determined according to the application from the influence time of the multipath. By setting Tg longer than the influence time of multipath such as TV ghost or the like, the modulated signal from the inverse FFT circuit 40 at the time of reception becomes one signal by the parallel / serial converter 40b and is transmitted as an RF signal by the transmitter 5.

Next, the operation of the receiver 43 will be described. 12
4 time axis symbol signal 796e. The received signal is input to the input section 24 of FIG. 123, input to the modulation section 852b, digitized, expanded into Fourier coefficients by the FFT section 40a, and as shown in FIG.
To the frequency axis 793a. From the time axis symbol signal of FIG. 124, the frequency axis signal carrier 794
a, 794b, etc. Since these carriers are orthogonal to each other, each modulated signal can be separated. The 16SRQAM or the like shown in FIG. 125 (b) is demodulated and sent to the respective C-CDM demodulators 45a, 45b and the like. Then, each C-CDM demodulator 4 of the C-CDM demodulator 45
5a, b, etc., demodulated hierarchically to demodulate the D ₁ and D ₂ sub-signals, and the D ₁ parallel-serial converter 852a and the D ₂ parallel-serial converter 852b convert the original D ₁ and D ₂ signals into serial signals. Demodulated. In this case, FIG.
Since the hierarchical transmission method using C-CDM as shown in FIG. 5 (b) is used, D ₁ is set under the reception condition of poor C / N value.
Only the signal is demodulated, and in good reception conditions both the D ₁ and D 2 signals are demodulated. The demodulated D ₁ signal is output from the output unit 75.
Demodulated at 7. Because of the high code cane D _1-1 signal error correction as compared with D _1-2 signal, an error signal of the D _1-1 signal is reproduced even in bad conditions with more reception condition. D _1-
1 signal is LDTV by the 1st-1 image decoder 402c
Becomes a low frequency signal, D _1-2 signal becomes a signal of the middle frequency component of the EDTV by a 1-2 video decoder 402d, and output.

The D ₂ signal is trellis-decoded, and is output as a high frequency component of HDTV by the second image decoder 402b. LDTV is output only with the above low-frequency signals,
A wide NTSC grade EDTV signal is output by adding the mid-range component, and an HDTV signal is synthesized by adding the high-range component. As in the previous embodiment, a TV signal of image quality according to the reception C / N can be received. In the case of the ninth embodiment, by using OFDM and C-CDM in combination, it is possible to realize hierarchical transmission that cannot be realized by OFDM itself. As shown in the error rate C / N of FIG. 130, the C-CDM-OFD of the present invention is compared with the curve 805 of the conventional OFDM-TCM modulated signal.
In the M method, the error rate of sub-channel 1 807a decreases and the error rate of sub-channel 2 807b increases. In this way, a hierarchical structure is realized.

Since OFDM certainly contains multipath interference signals during the guard period Tg, it is strong against multipath such as TV ghost. Therefore, it can be used for digital TV broadcasting for TV receivers of automobiles. However, since it is not a hierarchical transmission, it cannot be received below a certain C / N threshold. By combining with the C-CDM of the present invention, two of image reception (Graditional Degradation) that is strong against multipath and that corresponds to the deterioration of C / N can be realized. When receiving TV in a car, not only multipath but also C / N value deteriorates. Therefore, the service area of the TV broadcasting station is not expanded so much only by the measures against multipath. However, by combining with C-CDM of hierarchical transmission, LDTV grade can be received even if C / N is considerably deteriorated. On the other hand, in the case of an automobile TV, since the screen size is usually 100 inches or less, a sufficient image quality can be obtained with the LDTV grade. The effect is that the LDTV grade service area of a car TV is greatly expanded.
If OFDM is used in the entire band of HDTV, the circuit scale of DSP becomes large in the current semiconductor technology. So low-frequency TV
A method of transmitting only D _{1-1 of the} signal by OFDM will be shown. FIG.
As shown in the block diagram of FIG. 8, two of HDTV middle and high frequency components D _1-2 and D ₂ signals are C-CDM multiplexed according to the present invention, and are transmitted in the frequency band A by the FDM 40D. On the other hand, the signal received on the receiver side is frequency separated by the FDM 4oe and demodulated by the C-CDM demodulator 4b of the present invention.
In the same manner as in FIG. 123, the HDTV middle frequency component and high frequency component are reproduced. The operation of the image decoder in this case is the same as that in the first, second, and third embodiments, and therefore the description thereof is omitted.

[0348] Then D _1-1 signal is a low frequency signal of MPEG1 grade HDTV is in the OFDM converter 852C becomes parallel signals by the serial-parallel converter 791 QP
It receives SK or 16QAM modulation, is converted to a time axis signal by the inverse FFT unit 40, and is frequency band B by the FDM 40d.
Sent by.

On the other hand, the signal received by the receiver 43 is FD
The frequency is separated in the M section 40e, and the OFDM demodulation section 8
At 52d, the FFT 40a produces signals on many frequency axes, which are demodulated by the demodulators 45a and 45b, etc., and the D _1-1 signal is demodulated by the parallel-series converter 852a.
_{The 1-1} signal is output from the receiver 43.

In this way, hierarchical transmission is realized in which only LDTV signals are OFDM. By using the method of FIG. 138, the complex circuit of OFDM requires only LDTV signals. The LDTV signal has a bit rate of 1/20 as compared with the HDTV signal. Therefore, the circuit scale of OFDM is 1/2
It becomes 0, and the overall circuit scale is greatly reduced.

OFDM is a transmission method that is strong against multi-paths and is mainly applied to mobile stations such as when receiving mobile TVs or car TVs or when receiving digital music broadcasts from cars, where multi-path interference is large and fluctuates. I am trying to do. In such applications, a small screen size of 10 inches or less, which is 4 to 8 inches, is predominant. Therefore, the method of OFDM-modulating all high-resolution TV signals such as HDTV and EDTV is less effective for the cost, and reception of LDTV-grade TV signals is sufficient for automobile TV. On the other hand, in a fixed station such as a home TV, since multipath is always constant, it is easy to take measures against multipath. For this reason, it is OFD except in the strong ghost area.
The effect of M is not high. OFDM for mid-high range components of HDTV
The use of is not good in the present situation where the circuit scale of OFDM is large. Therefore, the method of using the OFDM shown in FIG. 138 of the present invention only for low-frequency TV signals does not lose the effect of OFDM, which greatly reduces the multipath interference of LDTV received by mobile stations such as automobiles. , OFDM
There is a great effect that the circuit scale can be greatly reduced to 1/10 or less.

[0352] Incidentally, OFDM only D _1-1 in Fig. 138
Modulation to have can be OFDM modulating the D _1-1 and D _1-2. In this case, since D _1-1 and D _1-2 is capable of 2 hierarchical transmission of C-CDM, hierarchical broadcasting is realized strong multi-pulse even in a mobile such as an automobile, in the mobile, L
Traditional Degradation that DTV and SDTV can receive images with image quality according to the reception level and antenna sensitivity
The effect of n is born.

In this way, the hierarchical transmission of the present invention becomes possible,
The various effects described above can be obtained. In the case of OFDM, since it is particularly strong against multipath, the effect that it is strong against multipath and the deterioration of the data transmission grade according to the deterioration of the reception level can be obtained by combining with the hierarchical transmission of the present invention.

As a method for realizing the hierarchical structure type transmission method, as shown in FIG. 126 (a), each sub-channel 794a-c of the FDM is set as the first layer 801a and each sub-channel 794d-f is set as the second layer 801b. By providing the frequency guard band 802a of fg in the middle and providing the power difference 802b of Pg as shown in FIG. 126 (b), the transmission power of the first layer 801a and the second layer 801b can be differentiated.

Utilizing this, FIG.
As shown in (d), the power of the first layer 801a can be increased within a range that does not interfere with analog TV broadcasting. In this case, as shown in FIG. 108 (e), the receivable threshold value of the C / N value of the first layer 801a is lower than that of the second layer 801b. Therefore, it is possible to obtain the effect that the first layer 801a can be received even in an area having a low signal level or an area having a lot of noise. As shown in FIG. 147, two-layer hierarchical transmission is realized. This is the Power-Weighted-OFDM system
(PW-OFDM) is called in the text. By combining the PW-OFDM of this embodiment with the above-mentioned C-CDM system of the present invention, there is an effect that the number of layers increases to three as shown in FIG. 108 (e), and the coverage area further expands. .

As a concrete circuit, as shown in FIG. 144, the first layer data is subjected to the inverse FFT with the carriers f _{1 to} f ₃ by the modulators 4 a to 4 c having large amplitude via the first data string circuit 791 a.
40, the second layer data is OFDM-modulated by the second data string circuit 791b and the modulators 4d to 4f having normal amplitudes are used.
Then, OFDM modulation is performed by the inverse FFT 40 on the carriers f _{6 to} f ₈ and transmission is performed.

The received signal is separated by the FFT 40a of the receiver 43 into signals having carriers f _{1 to} f _n , and the carriers f _{1 to} f ₃ are demodulated by the first data string D by the demodulators 45a to 45c.
_1, i.e. the first layer 801a is demodulated, the carrier f ₆ ~f ₈
From, the second data string D _2, that is, the second layer 801b is demodulated.

Since the power of the first layer 801a is large, the signal can be received even in an area where the signal is weak. Thus, PW-OFDM realizes two-layer hierarchical transmission. PW-OFDM to C-CD
When combined with M, a hierarchy of 3 to 4 layers is realized. The other operations in FIG. 144 are the same as those in the block diagram of FIG.

Next, the Time-Weighted-OFDM of the present invention will be described.
The layering method of (TW-OFDM) method is described. OFDM
Since the system has the guard time zone tg as described above, the ghost, that is, the delay time t _{M of the} multipath signal is t _M.
If the conditional expression <tg is satisfied, the influence of the ghost can be eliminated. In a fixed station such as a TV receiver of a general home, t
_{Since M} is as small as several μs and is constant, it is easy to cancel. However, in the case of a mobile station such as an in-vehicle TV receiver, there are many reflected waves, so t _M is not only large and close to several tens of μs, but it is difficult to cancel because it changes with movement. Therefore, it is expected that hierarchization for multipath will be required.

The hierarchical method of this embodiment will be described with reference to FIG.
As shown by 46, by making the guard time tga of the A-th layer larger than the guard time tgb of the B-th layer, the symbol of the sub-channel of the A-layer becomes strong against the ghost. In this way, weighting of guard time realizes hierarchical transmission for multipath. This method is called Guard-Time
-It is called Weighted-OFDM (GTW-OFDM).

Further, the symbol time Ts of the A layer and the B layer
When the number of symbols in A is set to the same number, the symbol time tsa of A is set to be larger than the symbol time tsb of B. As a result, Δfa> Δfb, where Δfa and Δfb are the intervals between A and B carriers on the frequency axis.
Is. Therefore, the error rate when demodulating the A symbol is lower than that of the B symbol. In this way, by differentiating the weighting of the symbol time Ts, a two-layer hierarchy is realized for the multipaths of the A-th layer and the B-th layer.
This method is called Carrier-Spacing-Weighted-OFDM (CSW-OFDM).
Call. Realizing two-layer transmission using GTW-0FDM, and transmitting low-resolution TV signals in layer A and high-frequency components in layer B, there are many ghosts like in-vehicle TV receivers. Stable reception of low-resolution TV is possible even under the condition reception. In addition, by differentiating the symbol time ts using CSW-OFDM, the layering for the C / N of the A layer and the B layer is GTW-.
By combining with OFDM, a great effect that more stable reception can be realized in an in-vehicle TV having a low received signal level is realized. High resolution is not required for TVs for in-vehicle use and portable use. Since the time ratio of the symbol time including the low resolution TV signal is small, increasing the guard time alone does not significantly reduce the overall transmission efficiency. Therefore, using the GTW-OFDM of this embodiment, the low resolution T
Hierarchical type that balances mobile stations such as mobile TVs and vehicle-mounted TVs with fixed stations such as home TVs, with almost no effect on transmission efficiency by taking multipath measures with emphasis on V signals. It has a great effect of realizing TV broadcasting. In this case, by combining with CSW-OFDM or C-CDM as described above, layering of C / N is added, and more stable reception of mobile stations becomes possible.

The effect of multipath will be specifically described below.
As shown in FIG. 145 (a), in the case of the multipaths 810a to 810d having a short delay time, the signals of the first transmission and the second layer can be received, and the HDTV signal can be demodulated. However, FIG.
In the case of long multipaths 811a to 811d as shown in (b), demodulation cannot be performed because the guard time Tgb of the B signal of the second layer is short. In this case, the A signal of the first layer has a long guard time Tga, and therefore is not affected by multipath having a long delay time. As described above, since the B signal includes the high frequency component of TV and the A signal includes the low frequency component of TV, the LDTV can be reproduced on the vehicle-mounted TV, for example.
Further, since the symbol time Tsa of the first layer is set to be larger than Tsb, the first layer is strong against deterioration of C / N.

By thus differentiating the guard time from the symbol time, the two-dimensional hierarchy of OFDM can be realized with a simple structure. By combining guard time differentiation and C-CDM with the configuration shown in FIG. 123, both multipath and C / N value deterioration can be layered.

A detailed example will be described here.
The smaller the D / U ratio is, the more the multipath delay time T _M becomes because the reflected waves are larger than the direct waves. For example, FIG.
As shown in, when D / U <30 dB, the influence of the reflected wave becomes large and becomes 30 μs or more. 50 as shown in FIG.
By taking a Tg of μs or more, it is possible to receive even under the worst conditions. Therefore, as shown concretely in FIG. 149 (a), for a TV signal of 1 sec, 2 ms shown in FIG. 149 (b).
Of the symbols of the first layer 801a and the second layer 8
01b and the third layer 801c are divided into three hierarchical groups, which are shown in FIG. 149 (c). Guard time 797a, 797b, 797c of each group, that is, Tga, Tg
By weighting and setting b and Tgc to, for example, 50 μs, 5 μs, and 1 μs, layered broadcasting regarding multipath of three layers of layers 801a, 801b, and 801c as shown in FIG. 150 is realized. When GTW-OFDM is applied to all image qualities, the transmission efficiency naturally lowers. However, by taking measures against the multipath of GTW-OFDM only for the image quality signal of LDTV having a small amount of information, there is an effect that the overall transmission efficiency does not decrease so much. Particularly, in the first layer 801a, the guard time Tg is 5 μs of 30 μs or more.
Since it is kept at 0 μs, it can be received even by a vehicle-mounted TV receiver. As the circuit, the one shown in the block diagram of FIG. 127 is used. In particular, since a vehicle-mounted TV has an image quality of LDTV grade, a transmission capacity of about 1 Mbps of MPEG1 class is sufficient. Therefore, as shown in FIG.
If aTsa is 200 μs for a cycle of 2 ms, 2M
Since it is possible to obtain bps, it is close to 1 Mbps even if the symbol rate is reduced to half, and LDTV grade image quality can be obtained. Therefore, CSW-OFDM of the present invention slightly lowers transmission efficiency but lowers error rate. In particular, when the C-CDM of the present invention is combined with GTW-OFDM, the transmission efficiency does not decrease and the effect is even higher. Figure 1
In 49, the symbol time is 796 for the same number of symbols.
a, 796b, 796c for 200 μs, 150 μs, 1
Differentiated to 00 μs. Therefore, the layer-type transmission is such that the error rate increases in the order of the first layer, the second layer, and the third layer.

At the same time, hierarchical transmission is realized for C / N. As shown in FIG. 151, CSW-OFDM and CSW
-A combination of OFDM realizes two-dimensional hierarchical transmission of multipath and C / N. As mentioned above, CSW-
It can also be realized by combining OFDM and the C-CDM of the present invention, and in this case, there is an effect that there is little reduction in the overall transmission efficiency. In the first layer 801a, the first-second layer 851a, and the first-third layer 851a, the multipath T _M is large and C /
LDTV grade stable reception is possible even in applications where N is low, such as in-vehicle TV Receiver. In the second layer 801b and the second to third layers 851b, the C / N is low like the fringe area of the service area, and standard-definition SDTV grade reception can be performed in a fixed station in a reception area with many ghosts. In the third layer 801c, which occupies more than half of the service area, the C / N is high, the direct wave is large, and the ghost is small, so that image quality of HDTV grade can be received.
In this way, two-dimensional hierarchical broadcasting of C / N and multipath is realized. As described above, the great effect is the GTW-OF of the present invention.
Combination of DM and C-CDM or GTW-OFD
Obtained by the combination of M and CSW-C-CDM.
Hitherto, a hierarchical broadcast system for C / N has been proposed, but the present invention realizes a two-dimensional matrix-type hierarchical broadcast of C / N and multipath.

Specific HDTV, SDTV, LDTV of two-dimensional layered broadcasting of three layers of C / N and three layers of multipath.
FIG. 152 shows a time arrangement diagram of TV signals of the three layers. As shown in the figure, an LDTV is arranged in the slot 796a1 of the first layer of the A layer, which is strong against multipath, and then the slot 796a2 resistant to multipath and the slot 796b1 resistant to C / N deterioration.
Are important HP such as SDTV sync signals and address signals.
Place the signal. General signals of SDTV, that is, LP signals and HP signals of HDTV are arranged in the second and third layers of the B layer. SDTV, EDTV, HD in C layer 1, 2 and 3 layers
A high frequency component TV signal such as a TV is arranged.

In this case, the stronger the resistance to CN deterioration or multipath, the lower the transmission rate and the lower the resolution of the TV signal. As shown in FIG. 153, three-dimensional Gracefu is obtained.
According to the present invention, an effect not achieved in the related art that 1 Degradation is realized can be obtained. FIG. 153 shows the hierarchical broadcasting of the three-dimensional structure of the present invention by the three parameters of CNR, multipath delay time and transmission rate.

An embodiment will be described using an example in which a two-dimensional hierarchical structure is obtained by a combination of GTW-OFDM of the present invention and the above-mentioned C-CDM of the present invention or a combination of GTW-OFDM and CSW-C-CDM. I did GTW-O
Two-dimensional layered broadcasting can be realized by combining FDM and Power-Weighted-OFDM or combining GTW-OFDM and other CNR layered transmission systems.

FIG. 154 shows carriers 794a, 794c,
The power of 794e is supplied to the carriers 794b, 794d, 794.
It is transmitted with a smaller weight than that of f, and realizes 2-layer Power-Weighted-OFDM. Carriers 795a, 7 orthogonal to the carrier 794a
Similarly, the power of 95c is applied to carriers 795b and 795d.
Two layers can be obtained by weighting the power with respect to. A total of four layers can be obtained, but FIG. 154 shows an example in the case of two layers. As shown in the figure, since the carrier frequency distribution is dispersed, interference with other analog broadcasts and the like in the same frequency band is dispersed, so that the effect is small.

Also, as shown in FIG. 155, one symbol 7
Guard time 797a for every 96a, 796b, 796c,
Hierarchical multilevel transmission for three-layer multipath is realized by taking the time arrangement in which the time widths of 797b and 797c are changed. In the time arrangement of FIG. 155, layers A and B
The data of layers C and C are dispersed on the time axis. Therefore, even if burst noise occurs at a specific time, the data in each layer is interleaved so that the data is prevented from being destroyed and the TV signal can be stably demodulated. In particular, by dispersing the data of layer A and applying interleaving, it is possible to greatly reduce the interference of burst noise generated from the ignition device of another vehicle when receiving the vehicle-mounted TV.

Specific ECC encoder 7 in this case
44j and block diagram of ECC decoder 749j are shown in FIG.
60 (a) and (b) respectively. In addition, in FIG.
The block diagram of the interleave part 936b is shown. Deinterleave RAM 9 of the deinterleave unit 936b
Interleave table 954 processed in 36a
Is shown in FIG. 168 (a), and the interleave distance L1 is shown in FIG. 168 (b).

By interleaving the data in this way, the interference of burst noise can be reduced.
A block diagram of the VSB receiver of FIG. 161 and VS of FIG. 162.
As shown in the block diagram of the B transmitter, the burst can be obtained by using the 4VSB, 8VSB, 16VSB transmission device described in the embodiments 4, 5, and 6 and the QAM and PSK transmission devices described in the embodiments 1 and 2. Since the interference of noise can be reduced, there is an effect that TV reception with less noise can be performed in terrestrial broadcasting.

[0373] By performing the three-layer broadcast by the system of Fig. 155, the layer A can reduce the interference of burst noise in addition to the above-mentioned multipath and C / N deterioration, and thus the vehicle-mounted TV
This has the effect of stabilizing LDTV grade TV reception by mobile stations such as receivers and pocket TVs.

The present invention is applicable to ASK, QAM, PSK, OFD.
Although the embodiment has been described using the M modulation method, the same effect can be obtained with other modulation methods. Further, by using the partial response, the error rate can be reduced not only in the recording system but also in the transmission system.

One feature of the multilevel transmission system of the present invention is to improve the frequency utilization efficiency, but for some receivers, the power utilization efficiency is considerably reduced. Therefore, it cannot be applied to all transmission systems. For example, in the case of a satellite communication system between specific receivers, the most economical method is to replace the device with the highest frequency use efficiency and the highest power use efficiency obtained at that time. In such a case, it is not always necessary to use the present invention.

However, in the case of the satellite broadcasting system or the terrestrial broadcasting system, the hierarchical transmission system as in the present invention is required. This is because satellite broadcasting standards require durability of 50 years or more. During this period, the broadcasting standard will not be changed, but the transmission power of the satellite will be dramatically improved with technological innovation. Broadcasters must provide compatible broadcasts so that even receivers manufactured at this time can receive and watch TV programs in the decades to come. Using the present invention, existing NTS
The effects of compatibility between C broadcasting and HDTV broadcasting and expandability of future information transmission amount can be obtained.

The present invention attaches importance to frequency efficiency rather than power efficiency, but the receiver side is provided with a designed receiving sensitivity according to each transmission stage, and transmission is performed by setting several kinds of receivers. There is no need to increase the power of the machine so much.
For this reason, it is possible to sufficiently transmit even the present low-satellite. Further, even if the transmission power increases in the future, the same standard can be used for transmission, so that future expandability and compatibility between old and new receivers can be obtained. As described above, the present invention has remarkable effects when used in the satellite broadcasting standard.

When the multilevel transmission system of the present invention is used for terrestrial broadcasting, the present invention is easier to carry out than satellite broadcasting, because it is not necessary to consider the power utilization efficiency. As described above, there is a remarkable effect of greatly reducing the unreceivable area in the service area that existed in the conventional digital HDTV broadcasting system, and the effect of compatibility between the NTSC and the HDTV receiver or the receiver described above. There is also an effect that the service area is substantially expanded when viewed from the TV program sponsor. In the embodiment, QPSK, 16QAM, 32
The description has been made using the example using the modulation method of QAM and 4VSB, 8VSB, 16VSB, but 64QAM, 128QA
It goes without saying that it can be applied to M, 256QAM, 32VSB, 64VSB and the like. Needless to say, it can be applied to multi-level PSK, ASK, and FSK as described with reference to the drawings. Although the embodiment in which the present invention and TDM are combined and transmitted has been described, it is also possible to combine and transmit FDM, CDMA and spread spectrum communication systems.

One of the features of the multilevel transmission system of the present invention is to improve the frequency utilization efficiency, but the power utilization efficiency is considerably reduced for some receivers. Therefore, it cannot be applied to all transmission systems. For example, in the case of a satellite communication system between specific receivers, the most economical method is to replace the device with the highest frequency use efficiency and the highest power use efficiency obtained at that time. In such a case, it is not always necessary to use the present invention.

However, in the case of the satellite broadcasting system or the terrestrial broadcasting system, the multilevel transmission system as in the present invention is required. This is because satellite broadcasting standards require durability of 50 years or more. During this period, the broadcasting standard will not be changed, but the transmission power of the satellite will be dramatically improved with technological innovation. Broadcasters must provide compatible broadcasts so that even receivers manufactured at this time can receive and watch TV programs in the decades to come. Existing NTSC with the present invention
The effects of compatibility between broadcasting and HDTV broadcasting and expandability of future information transmission amount can be obtained.

Although the present invention emphasizes frequency efficiency rather than power efficiency, the receiver side is provided with a designed reception sensitivity according to each transmission stage, and transmission is performed by setting several kinds of receivers. There is no need to increase the power of the machine so much.
For this reason, it is possible to sufficiently transmit even the present low-satellite. Further, even if the transmission power increases in the future, the same standard can be used for transmission, so that future expandability and compatibility between old and new receivers can be obtained. As described above, the present invention has remarkable effects when used in the satellite broadcasting standard.

When the multilevel transmission system of the present invention is used for terrestrial broadcasting, the present invention is easier to carry out than satellite broadcasting because it is not necessary to consider the power utilization efficiency. As described above, there is a remarkable effect of greatly reducing the unreceivable area in the service area that existed in the conventional digital HDTV broadcasting system, and the effect of compatibility between the NTSC and the HDTV receiver or the receiver described above. There is also an effect that the service area is substantially expanded when viewed from the TV program sponsor. In the embodiment, the example using the modulation system of 16QAM and 32QAM has been described, but 64QAM and 1
It goes without saying that it can be applied to 28QAM, 256QAM and the like. In addition, as described with reference to the figure, multivalued PS
It goes without saying that it can be applied to K, ASK, and FSK.

[0383]

As described above, the present invention includes a signal input section,
A transmission device for transmitting data, which includes a modulation unit that modulates a plurality of carrier waves having different phases by an input signal from the input unit to generate an m-value signal point on a signal vector diagram, and a transmission unit that transmits the modulated signal. In, the first data sequence and the second data sequence of n values are input, the signal is divided into n signal point groups, and each of the signal point groups is assigned to the data of the first data sequence, Allocate each data of the second data group to each signal point inside, and transmit the signal by the transmitter that transmits,
In the receiver having the input part of the transmission signal, the demodulator for demodulating the QAM modulated wave of the p-valued signal point on the signal space diagram, and the output part, the signal points are divided into n-valued signal point groups, and The signal point group is demodulated in correspondence with the n-valued first data string, and the data of the p / n-valued second data string is demodulated and reproduced at the substantially p / n-valued signal points in the signal point group and received. By transmitting data using the device, for example, the modulator 4 of the transmitter 1 allocates the data of the first data sequence, the second data sequence, and the third data sequence of n values to the signal point group and transforms them. Value QA
The M-modulated signal is transmitted, and in the first receiver 23, the demodulator 25
The first data string of n value is
By demodulating the data sequence and the second data sequence, and the third receiver 43 demodulating the first data sequence, the second data sequence, and the third data sequence, the multi-level modulated wave that is obtained by modulating the maximum m-value data is effectively obtained. It is possible to obtain a compatible and expandable transmission device capable of demodulating n-valued data even with a receiver having an n-valued demodulating ability of n <m. Further, when the distance between the signal point closest to the origin and the I-axis or the Q-axis among the signal points of the QAM system is f, the signal points are shifted so that the distance is nf such that n> 1. , Hierarchical transmission becomes possible.

By transmitting the NTSC signal as the first data string and the difference signal between HDTV and NTSC as the second data string to this transmission system, there is compatibility between NTSC broadcasting and HDTV broadcasting in satellite broadcasting, and Highly scalable digital broadcasting becomes possible, and terrestrial broadcasting has the remarkable effect of expanding the service area and eliminating unreceivable areas.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an entire system of a transmission device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a transmitter 1 according to the first embodiment of the present invention.

FIG. 3 is a vector diagram of a transmission signal according to the first embodiment of the present invention.

FIG. 4 is a vector diagram of a transmission signal according to the first embodiment of the present invention.

FIG. 5 is a diagram of assigning codes to signal points according to the first embodiment of the present invention.

FIG. 6 is a coding diagram for a signal point group according to the first embodiment of the present invention.

FIG. 7 is a coding diagram of signal points in a signal point group according to the first embodiment of the present invention.

FIG. 8 is a signal point group according to the first embodiment of the present invention and a coding diagram for the signal points.

FIG. 9 is a threshold state diagram of a signal point group of a transmission signal according to the first embodiment of the present invention.

FIG. 10 is a vector diagram of modified 16-value QAM according to the first embodiment of the present invention.

FIG. 11 is a diagram showing the relationship between the antenna radius r ₂ and the transmission power ratio n according to the first embodiment of the present invention.

FIG. 12 is a diagram of modified 64-value QAM signal points according to the first embodiment of the present invention.

FIG. 13 is a diagram showing the relationship between the antenna radius r ₃ and the transmission power ratio n according to the first embodiment of the present invention.

FIG. 14 is a vector diagram of a modified 64-value QAM signal group and sub-signal point group according to the first embodiment of the present invention.

FIG. 15 is an explanatory diagram of modified 64-value QAM ratios A ₁ and A _{2 according to} the _first embodiment of the present invention.

FIG. 16 is a relational diagram of antenna radii r ₂ and r ₃ and transmission power ratios n ₁₆ and n _{64 according to} the first embodiment of the present invention.

FIG. 17 is a block diagram of the digital transmitter according to the first embodiment of the present invention.

FIG. 18 is a signal space diagram diagram of 4PSK modulation according to the first embodiment of the present invention.

FIG. 19 is a block diagram of a first receiver according to the first embodiment of the present invention.

FIG. 20 is a signal space diagram diagram of the 4PSK modulation signal according to the first embodiment of the present invention.

FIG. 21 is a block diagram of a second receiver according to the first embodiment of the present invention.

FIG. 22 is a signal vector diagram of modified 16-level QAM according to the first embodiment of the present invention.

FIG. 23 is a signal vector diagram of modified 64-value QAM according to the first embodiment of the present invention.

FIG. 24 is a flowchart of the first embodiment of the present invention.

25A is a signal vector diagram of 8-value QAM according to the first embodiment of the present invention, and FIG. 25B is a signal vector diagram of 16-value QAM according to the first embodiment of the present invention.

FIG. 26 is a block diagram of a third receiver according to the first embodiment of the present invention.

FIG. 27 is a diagram of signal points of modified 64-value QAM according to the first embodiment of the present invention.

FIG. 28 is a flowchart of the first embodiment of the present invention.

FIG. 29 is an overall configuration diagram of a transmission system according to a third embodiment of the present invention.

FIG. 30 is a block diagram of a first image encoder according to a third embodiment of the present invention.

FIG. 31 is a block diagram of a first image decoder according to the third embodiment of the present invention.

FIG. 32 is a block diagram of a second image decoder according to the third embodiment of the present invention.

FIG. 33 is a block diagram of a third image decoder according to the third embodiment of the present invention.

FIG. 34 is an explanatory diagram of time multiplexing of D ₁ , D ₂ , and D ₃ signals according to the _third embodiment of the present invention.

FIG. 35 is an explanatory diagram of time multiplexing of D ₁ , D ₂ , and D ₃ signals according to the _third embodiment of the present invention.

FIG. 36 is an explanatory diagram of time multiplexing of D ₁ , D ₂ , and D ₃ signals according to the _third embodiment of the present invention.

FIG. 37 is a configuration diagram of the entire system of a transmission device according to a fourth embodiment of the present invention.

FIG. 38 is a vector diagram of signal points of modified 16QAM according to the third embodiment of the present invention.

FIG. 39 is a vector diagram of signal points of modified 16QAM according to the third embodiment of the present invention.

FIG. 40 is a vector diagram of signal points of modified 64QAM according to the third embodiment of the present invention.

FIG. 41 is a signal arrangement diagram on the time axis according to the third embodiment of the present invention.

FIG. 42 is a signal arrangement diagram on the time axis of the TDMA system according to the third embodiment of the present invention.

FIG. 43 is a block diagram of a carrier recovery circuit according to a third embodiment of the present invention.

FIG. 44 is a principle diagram of carrier wave reproduction according to the third embodiment of the present invention.

FIG. 45 is a block diagram of an inverse modulation carrier recovery circuit according to a third embodiment of the present invention.

FIG. 46 is a signal point arrangement diagram of 16QAM signals according to the third embodiment of the present invention.

FIG. 47 is a signal point arrangement diagram of 64QAM signals according to the third embodiment of the present invention.

FIG. 48 is a block diagram of a carrier multiplication circuit of 16 multiplication system according to a third embodiment of the present invention.

[FIG. 49] D _V1 , D _H1 , D _{V2 of} Example 3 of the present invention,
Illustration of time multiplexing of D _H2 , D _V3 , and D _H3 signals

[FIG. 50] D _V1 , D _H1 , D _{V2 of} Example 3 of the present invention,
Explanatory drawing of TDMA time multiplexing of D _H2 , D _V3 and D _H3 signals

FIG. 51 shows D _V1 , D _H1 , D _{V2 of} the third embodiment of the present invention,
Explanatory drawing of TDMA time multiplexing of D _H2 , D _V3 and D _H3 signals

FIG. 52 is a reception interference area diagram of a conventional method in Embodiment 4 of the present invention.

[Fig. 53] Fig. 53 is a reception interference area diagram in the case of the hierarchical broadcasting system according to the fourth embodiment of the present invention

FIG. 54 is a diagram showing a reception interference area of the conventional method in the fourth embodiment of the present invention.

[Fig. 55] Fig. 55 is a reception interference area diagram in the case of the hierarchical broadcasting system according to the fourth embodiment of the present invention

FIG. 56 is a digital broadcasting station 2 according to the fourth embodiment of the present invention.
Station interference area map

FIG. 57 is a signal point arrangement diagram of a modified 4ASK signal according to the fifth embodiment of the present invention.

FIG. 58 is a signal point arrangement diagram of modified 4ASK according to the fifth embodiment of the present invention.

FIG. 59 (a) is a modification 4A of the fifth embodiment of the present invention.
Signal point constellation diagram of SK (b) is a signal point constellation diagram of modified 4ASK in the fifth embodiment of the present invention

FIG. 60 is a signal point arrangement diagram of a modified 4ASK signal in the case of a low C / N value according to the fifth embodiment of the present invention.

FIG. 61 is a 4VSB, 8VSB transmitter according to the fifth embodiment.

FIG. 62 (a) is a spectrum diagram of an ASK signal in the fifth embodiment of the present invention, that is, a multi-valued VSB signal for filtering, and (b) is a frequency distribution diagram of the VSB signal in the fifth embodiment of the present invention.

FIG. 63 shows 4VSB, 8VSB, and 16 in Example 5.
VSB Receiver block diagram

FIG. 64 is a block diagram of a video signal transmitter according to a fifth embodiment of the present invention.

FIG. 65 is a block diagram of the entire TV receiver in Embodiment 5 of the present invention.

FIG. 66 is a block diagram of another TV receiver in Embodiment 5 of the present invention.

FIG. 67 is a block diagram of a satellite / terrestrial TV receiver in Embodiment 5 of the present invention.

68 (a) is a C of 8VSB in Examples 5 and 6. FIG.
The onstellation diagram (b) shows the 8VSB of the constellation in Examples 5 and 6.
(c) Signal vs. time waveform diagram of 8VSB in Examples 5 and 6

FIG. 69 is another block diagram of the image encoder according to the fifth embodiment of the present invention.

FIG. 70 is a block diagram of an image encoder having one separation circuit according to the fifth embodiment of the present invention.

FIG. 71 is a block diagram of an image decoder according to the fifth embodiment of the present invention.

FIG. 72 is a block diagram of an image decoder having one combiner according to the fifth embodiment of the present invention.

FIG. 73 is a time allocation diagram of transmission signals according to the fifth embodiment of the present invention.

FIG. 74 (a) is a block diagram of an image decoder of Embodiment 5 according to the present invention, and (b) is a time allocation diagram of transmission signals of Embodiment 5 according to the present invention.

FIG. 75 is a time allocation diagram of transmission signals according to the fifth embodiment of the present invention.

FIG. 76 is a time allocation diagram of transmission signals according to the fifth embodiment of the present invention.

FIG. 77 is a time allocation diagram of transmission signals according to the fifth embodiment of the present invention.

FIG. 78 is a block diagram of an image decoder according to a fifth embodiment of the present invention.

FIG. 79 is a time allocation diagram of transmission signals of three layers according to the fifth embodiment of the present invention.

FIG. 80 is a block diagram of an image decoder according to a fifth embodiment of the present invention.

FIG. 81 is a time allocation diagram of transmission signals according to the fifth embodiment of the present invention.

FIG. 82 is a block diagram of an image decoder of D1 according to Example 5 of the present invention.

FIG. 83 is a frequency-time diagram of the frequency modulation signal according to the fifth embodiment of the present invention.

FIG. 84 is a block diagram of a magnetic recording / reproducing apparatus in a fifth embodiment according to the present invention.

FIG. 85 is a diagram showing the relationship between the C / N and the layer number according to the second embodiment of the present invention.

FIG. 86 is a relationship diagram between transmission distance and C / N according to the second embodiment of the present invention.

FIG. 87 is a block diagram of a transmitter according to a second embodiment of the present invention.

FIG. 88 is a block diagram of a receiver according to the second embodiment of the present invention.

FIG. 89 is a relational diagram of C / N-error rate according to the second embodiment of the present invention.

FIG. 90 is a diagram showing a reception interference area of three layers according to the fifth embodiment of the present invention.

[Fig. 91] Fig. 91 is a diagram illustrating a 4-layer reception interference region according to the present invention.

FIG. 92 is a hierarchical transmission diagram of the sixth embodiment according to the present invention.

FIG. 93 is a block diagram of a separation circuit according to a sixth embodiment of the present invention.

FIG. 94 is a block diagram of a synthesis unit according to the sixth embodiment of the present invention.

FIG. 95 is a transmission hierarchical structure diagram of Embodiment 6 according to the present invention.

FIG. 96 is a reception state diagram of a conventional digital TV broadcast.

[FIG. 97] FIG. 97 is a reception state diagram of a digital TV hierarchical broadcast according to a sixth embodiment of the present invention.

FIG. 98 is a transmission hierarchical structure diagram of Embodiment 6 according to the present invention.

FIG. 99 is a vector diagram of 16SRQAM of Example 3 according to the present invention.

FIG. 100 is a vector diagram of 32SRQAM according to the third embodiment of the present invention.

FIG. 101 is a relationship diagram of C / N-error rate according to the third embodiment of the present invention.

FIG. 102 is a relational diagram of C / N-error rate according to the third embodiment of the present invention.

103 is a diagram showing the relationship between the shift amount n and the C / N required for transmission according to the third embodiment of the present invention. FIG.

FIG. 104 is a diagram showing the relationship between the shift amount n and the C / N required for transmission according to the third embodiment of the present invention.

FIG. 105 is a distance from the transmitting antenna and a signal level during terrestrial broadcasting according to the third embodiment of the present invention.

FIG. 106 is a service area diagram of 32SRQAM according to the third embodiment of the present invention.

FIG. 107 is a service area diagram of 32SRQAM according to the third embodiment of the present invention

108A is a frequency distribution diagram of a conventional TV signal, FIG. 108B is a frequency distribution diagram of a conventional two-level TV signal, and FIG. 108C is a diagram showing a threshold value of the third embodiment of the present invention. Is a frequency distribution diagram of the carrier groups of the two-layered OFDM of the ninth embodiment. (E) is a diagram showing three threshold values of the three modified OFDM of the ninth embodiment.

FIG. 109 is a TV signal time allocation diagram according to the third embodiment of the present invention.

FIG. 110 is a principle diagram of C-CDM of Example 3 according to the present invention.

FIG. 111 is a code assignment diagram according to the third embodiment of the present invention.

FIG. 112 is a code allocation diagram when 36QAM of the third embodiment according to the present invention is extended.

FIG. 113 is a modulation signal frequency allocation diagram according to the fifth embodiment of the present invention.

FIG. 114 is a block diagram of a magnetic recording / reproducing apparatus in Example 5 according to the present invention.

FIG. 115 is a block diagram of a transmitter / receiver of a mobile phone according to a seventh embodiment of the present invention.

FIG. 116 is a block diagram of a base station according to Example 7 of the present invention.

FIG. 117 is a distribution chart of communication capacity and traffic in the conventional method.

FIG. 118 is a distribution diagram of communication capacity and traffic according to the seventh embodiment of the present invention

FIG. 119 (a) is a time slot arrangement diagram of a conventional method, and (b) is a time slot arrangement diagram of the seventh embodiment according to the present invention.

FIG. 120 (a) is a TDMA system time slot layout diagram of a conventional system, and (b) is a TDMA system time slot layout diagram of Example 7 according to the present invention.

FIG. 121 is a block diagram of a one-layer transceiver according to the seventh embodiment of the present invention.

FIG. 122 is a block diagram of a two-layer transceiver according to the seventh embodiment of the present invention.

FIG. 123 is a block diagram of an OFDM transceiver according to an eighth embodiment of the present invention.

FIG. 124 is a diagram illustrating the principle of operation of the OFDM system according to the eighth embodiment of the present invention.

FIG. 125 (a) is a frequency allocation diagram of a modulation signal of a conventional system, and (b) is a frequency allocation diagram of a modulation signal of Example 8 according to the present invention.

126A is a Weig of OFDM in Embodiment 9. FIG.
FIG. 7B shows a state in which no hting is performed. FIG. 8B shows two subchannels of the two-layered OFDM weighted by the transmission power in the ninth embodiment.
(e) is a frequency distribution map of OFDM with carrier spacing without weighting according to the ninth embodiment.

FIG. 127 is a block diagram of a transceiver of Example 9 according to the present invention.

FIG. 128 (a) is Tre in Examples 2, 4, and 5.
Block diagram of lls Encoder (Ratio1 / 2) (b) shows Trellis E in Examples 2, 4 and 5.
Block diagram of coder (Ratio 2/3) (c) shows Trellis E in Examples 2, 4, and 5.
Block diagram of coder (Ratio 3/4) (d) shows Trellis D in Examples 2, 4, and 5.
(e) is a block diagram of the encoder (Ratio1 / 2), and Trellis D in Examples 2, 4, and 5.
(f) is a block diagram of the ecoder (Ratio 2/3), and Trellis D in Examples 2, 4, and 5.
block diagram of ecoder (Ratio 3/4)

FIG. 129 is a time allocation diagram of the effective symbol period and the guard period according to the ninth embodiment.

FIG. 130 is a relational diagram of C / N vs. error rate of the conventional example and the ninth example.

131 is a block diagram of a magnetic recording / reproducing apparatus in Example 5. FIG.

132 is a recording format of tracks on the magnetic tape of Example 5 and a running diagram of the head. FIG.

FIG. 133 is a block diagram of a transceiver according to the third embodiment.

[FIG. 134] A frequency allocation diagram of a conventional broadcasting system

FIG. 135 is a diagram showing the relationship between the service area and the image quality when the three-layer hierarchical transmission system of the third embodiment is used.

[FIG. 136] FIG. 136 is a frequency allocation diagram in the case where the hierarchical transmission system of the third embodiment and FDM are combined.

137] FIG. 137 is a block diagram of a transceiver when trellis coding is used in Embodiment 3. [FIG.

138] FIG. 138 is a diagram illustrating a part of low-frequency signal OFD according to the ninth embodiment.
Block diagram of transceiver when transmitting by M

139] FIG. 139 is a signal point constellation diagram of 8-PS-APSK in Embodiment 1. [FIG.

FIG. 140 is a constellation diagram of 16-PS-APSK signal points according to the first embodiment.

141 is a signal point constellation diagram of 8-PS-PSK in Embodiment 1. FIG.

FIG. 142 is a diagram showing 16-PS-PSK (P in Example 1;
S type) signal point arrangement diagram

[FIG. 143] FIG. 143 is a relationship diagram between a radius of a satellite antenna and a transmission capacity in Embodiment 1.

144: Weighted OF in Example 9 FIG.
Block diagram of DM transceiver

145 (a) is a guard time when the multipath is short in the ninth embodiment, and a symbol time hierarchical OFDM waveform diagram (b) is a guard time when the multipath is long and the symbol time hierarchical type in the ninth embodiment Waveform diagram of OFDM

[FIG. 146] FIG. 146 is a principle diagram of a guard time / symbol time hierarchical OFDM in Embodiment 9.

FIG. 147 is a sub-channel arrangement diagram of a two-layer transmission system by power weighting according to the ninth embodiment.

148] FIG. 148 is a relationship diagram of D / V conversion, multipath delay time, and guard time in Embodiment 9. [FIG.

149 (a) is a time slot diagram of each layer in the ninth embodiment, (b) is a time distribution diagram of guard time of each layer in the ninth embodiment, and (c) is a guard of each layer in the ninth embodiment Time distribution diagram of time

FIG. 150 is an explanatory diagram of a layered broadcasting system of three layers for multipath in the relationship diagram between the multipath delay time and the transmission rate diagram of the ninth embodiment.

151] GTW-OFDM and C-CDM of Example 9 [FIG.
(Or CSW-OFDM) combination is an explanatory view of a hierarchical broadcasting system having a two-dimensional matrix structure in the relationship diagram between the delay time and the CN value

[FIG. 152] A GTW-OFDM and C-CDM of Example 9.
(Or CSW-OFDM) combination time allocation diagram of TV signals of three layers in each time slot

153] GTW-OFDM and C-CDM of Example 9. [FIG.
(Or CSW-OFDM) combination is an explanatory view of a hierarchical broadcasting system having a three-dimensional matrix structure in a relationship diagram of a multipath signal delay time, a CN value, and a transmission rate.

154] Power-Weighted of Example 9. [FIG.
-Frequency distribution diagram of OFDM

FIG. 155: Guard-Time-OFD of Example 9
Layout diagram of TV signals of three layers in each time slot on the time axis when M and C-CDM are combined

156] FIG. 156 is a block diagram of a transmitter and a receiver in Embodiments 4 and 5. [FIG.

FIG. 157 is a block diagram of a transmitter and a receiver in Embodiments 4 and 5;

FIG. 158 is a block diagram of a transmitter and a receiver in Embodiments 4 and 5;

159 (a) is a 16VSB signal point constellation diagram in the fifth embodiment (b) is a 16VSB signal point constellation diagram in the fifth embodiment (8VSB) (c) is a 16VSB signal point constellation diagram in the fifth embodiment 4VSB) (d) is a 16VSB signal point arrangement diagram (16VSB) in the fifth embodiment.

FIG. 160 (a) shows ECC E in Examples 5 and 6.
The block diagram (b) of the coder is the ECC encoder in the fifth and sixth embodiments.
Block diagram of

FIG. 161 is an overall block diagram of a VSB receiver according to a fifth embodiment.

162] FIG. 162 is a diagram illustrating a transmitter in Embodiment 5. [FIG.

FIG. 163 Example 4 VSB and TC-8VSB error rate / C / N value curve

FIG. 164 is an error rate curve of subchannel 1 and subchannel 2 of Example 4 VSB and TC-8VSB.

FIG. 165 (a) is a Ree in Examples 2, 4, and 5.
d Solomon Encoder block diagram (b) is the Reed Solo in Examples 2, 5, and 6.
Block diagram of mon Decoder

FIG. 166 is a Reed Solom of Examples 2, 4, and 5.
on Flowchart of error correction and calculation

FIG. 167 is a block diagram of a deinterleave unit according to the second, third, fourth, fifth, and sixth embodiments.

168 (a) is a diagram of interleaving and de-interleaving tables in Examples 2, 3, 4, and 5 (b) is a diagram showing interleaving distances in Examples 2, 3, 4, and 5. FIG.

[FIG. 169] 4-VSB, 8-VS in Example 5
B, 16-VSB Redundancy comparison diagram

FIG. 170 High in Examples 2, 3, 4, and 5
TV Receive receiving Priority signal
Block diagram of r

171] FIG. 171 is a block diagram of a transmitter and a receiver in Embodiments 2, 3, 4, and 5.

172] FIG. 172 is a block diagram of a transmitter and a receiver in Embodiments 2, 3, 4, and 5.

FIG. 173 is a block diagram of an ASK type magnetic recording / reproducing apparatus according to a sixth embodiment.

[Explanation of symbols]

 1 transmitter 4 modulator 6 antenna 6a ground antenna 10 satellite 12 repeater 23 first receiver 25 demodulator 33 second receiver 35 demodulator 43 third receiver 51 digital transmitter 85 signal point 91 first split signal point Group 401 First image encoder 703 Receivable area of SRQAM

 ─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. 5-349972 (32) Priority date Hei 5 (1993) December 27 (33) Priority claim country Japan (JP)

Claims (5)

[Claims] 1. An image signal input means, an image compression means for compressing the image signal into a digital image compression signal, and an error correction coding for adding an error correction code to the digital image compression signal to produce an error correction coded signal. Means, a modulation means for modulating the error correction coded signal into an n-value VSB modulated signal, and a means for transmitting a transmission signal by a transmitter having a transmission means for transmitting the modulation signal, and means for receiving the transmission signal, Demodulation means for demodulating the transmission signal into a reception digital signal,
Error correction means for error-correcting the received digital signal into an error-corrected digital signal, an image expansion unit for expanding the error-corrected digital signal into a video output signal, and output means for outputting the video output signal A transmission device characterized by using a trellis encoder or a trellis decoder as error correction means in a device for transmitting an image signal by a receiver. 2. The transmission device according to claim 1, wherein the modulation means is a modulation means for modulating an 8-value VSB signal. 3. A received digital signal is divided into a high-importance signal and a low-importance signal, a first error correction means having a high error-encoding code gain in the error-correction means, and an error-encoding code. 2. The transmission device according to claim 1, wherein two second error correction means having a low gain are provided, and the first signal is corrected by the first error correction means. 4. As a high importance signal, header information including address information of image data divided in pixel block units is transmitted, and image data in the pixel block is transmitted as a low importance signal. The transmission device according to claim 3. 5. The transmission device according to claim 1, wherein the error coded signal is interleaved.