JP2834124B2 - Multiplex transmission method and signal generator thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]   The present invention relates to a multiplex transmission method, and particularly to a digital code transmission method.
Effective for transmitting multiplexed audio, etc. with video signals
Transmission method and a signal generation device thereof. [Conventional technology]   Multiplex digitally encoded PCM audio and video signals
For details on the method, see Radio Technology, issued in June 1983.
Report of the Technical Committee on Satellite Reception Technology, edited by the Association
Receiver, etc., but the current NTSC video signal
PCM audio is multiplexed using a subcarrier of 5.7272 MHz.
To satisfy the current terrestrial television broadcasting band
Therefore, it is difficult to use it for terrestrial television broadcasting.   On the other hand, multiplex transmission to current terrestrial television broadcasting is possible
Published by Japan Broadcasting Publishing Association in January 1983
Of the Japanese Broadcasting Society, edited by the Japan Broadcasting Corporation
Expressions on pages 205-208, but high quality audio
Approximately 1 Mbit / s transmission for transmitting 2 channels
There is no description about the method that can secure the capacity
Was. [Problems to be solved by the invention]   With the above conventional technology, high quality
There was no way to multiplex quality audio signals.   An object of the present invention is to multiplex an amplitude-modulated signal with another signal.
A transmission method and a signal generator for the case of double transmission are provided.
High quality, especially for current television broadcasts
Video signals such as digitally encoded audio signals
Transmission method for multiplexing transmission with less interference to signal and its signal
To provide a generator that is effective in generating the
You. [Means for solving the problem]   In order to achieve the above object, in the present invention, 1. A digitally encoded multiplex signal separate from the video signal
And a spectrum suppression process to suppress the reduced component.
Then, the multiplexed signal subjected to the pressing process is
Repeated every horizontal scanning period and adjacent horizontal scanning period
Performs correlation processing to reverse the phase relationship at the same timing
Multiplexed signal, the above-mentioned video carrier and quadrature
Amplitude-modulate the quadrature carrier and combine it with the residual sideband amplitude-modulated wave.
A multiplex transmission method for combining and transmitting, and signal generation
As a device 2.From the carrier generation circuit for transmitting the video signal,
A phase shifter that obtains a carrier and a spectrum near the video carrier
A spectral band suppression circuit to be reduced;
Converts another digitally encoded multiplex signal into a video signal
Repeated in horizontal scanning periods and adjacent horizontal scanning periods
Performs correlation processing to reverse the phase relationship at the same timing between
Processing circuit, and the output of the phase shifter is amplitude-modulated by this output.
Modulating circuit, the output of the modulating circuit and the vestigial sideband
And a combining circuit for combining the amplitude modulated wave.
Was. (Operation)   Vestigial sideband Amplitude modulated video signal carrier on both sides
Common amplitude modulated band (DSB) with waveband
And the carrier is orthogonally related to the video and audio signals.
Modulation with a stake in the video signal
Reduce the effect of voice signals. Where the modulation of the audio signal
Lower than the video signal for playback with envelope detection
To reduce the effect of audio signal on the video signal
There is. Also, since the audio signal is reproduced by synchronous detection,
Without demodulating orthogonally modulated video signals,
The effect of interference on the sound is reduced.   In addition, the receiver's amplitude modulation detection
Wave (also called pseudo-synchronous detection), a carrier recovery circuit
Carrier frequency selection band of carrier frequency selection circuit to configure
There is interference such as orthogonal multiplex signals within the
Phase jitter, resulting in phase fluctuations in the detection output
Image hindrance such as a change in hue of the image is given. Spectrum
The band suppression circuit is used to control the spectrum near the carrier frequency of the orthogonal multiplex signal.
Carrier in the carrier frequency selection circuit
Reduce the interfering signal from the
Hue change due to phase change caused by the signal
To reduce.   The same applies to amplitude modulation detection using the PLL synchronous detection method.
Of frequency response characteristics due to orthogonal multiplexing in band
Is caused by the orthogonal multiplex signal.
Hue change due to the phase change.   The multiplex signal is repeated in units of the horizontal scanning period of the video signal.
And repeat the same multiplex signal in adjacent horizontal scanning periods.
Transmitting in antiphase relationship multiplexes signals into quadrature components
Caused by phase fluctuations of the video signal carrier
On the screen of a television receiver using envelope detection
Hue change is reduced.   In addition, the current FM audio signal means both frequency and modulation
Because they are different, they are compatible without affecting each other. 〔Example〕   Hereinafter, embodiments of the present invention will be described with reference to the drawings. First
The figure shows a television signal transmission device according to an embodiment of the present invention.
It is a block diagram of a device. Digitize as multiplexed signal
The following describes an example of a tar-coded audio signal.   101 is audio signal input terminal, 102 is FM modulator, 103 is audio
Signal carrier generator, 104 is video signal input terminal, 105 is mat
Rix circuit, 106 is a luminance signal processing circuit, 107 is a color difference signal
Processing circuit, 108 is an addition circuit, 109 is a video modulator, 110 is a video
Image signal carrier generator, 111 digitally encoded and transmitted
Input terminal for audio signal to be used, 112 is an analog digital
Converter (hereinafter abbreviated as ADC), 113 is digital signal processing
Circuit, 114 is a ternary conversion circuit, 115 is a processing circuit, 116 is a low band
Pass filter, 117 is a transporter, 118 is digital coding
Modulator for audio signal, 119 equalizer, 120 add
121, a transmission VSB filter for vestigial sideband amplitude modulation, 12
2 is an adder, and 123 is an antenna.   Audio signal transmission with audio signal from audio signal input terminal 101
The carrier for voice from the wave generator 103 is converted to the FM modulator 102.
FM modulation. RGB primary colors input to video input terminal 104
The signal is divided into a luminance signal and a color difference signal by the matrix 105.
Each of the luminance signal processing circuit 106 and the color difference signal processing circuit 107
After the processing, the adder 108 adds. Projected by signal after addition
The carrier from the image signal carrier generator 110 is transmitted to the video modulator 109.
Modulated using the VSB filter 121 and transmitted by the television broadcast
After limiting the band to the band, the adder 122 adds the sound modulation wave and
The signal is transmitted from the antenna 123.   For the above, the conventional terrestrial transmission television broadcasting
Is the same as For transmitting high quality audio to the above signals
Add the following.   The audio signal to be multiplexed is applied to the input terminal 111, and the audio signal
Is converted to a digital signal by the ADC 112, and the digital signal is processed.
Circuit 113 for detecting and correcting errors that occur during transmission.
Add codes or perform interleave processing as described below.
Where The processed digital code is output by the ternary conversion circuit 114.
+ 1,0, -1 ternary digital signal from +1,0 binary digital signal
Digital signal, and the processing circuit 115
Repeat data multiple times in scan period units to
During the scanning period, data can be inverted and transmitted in reverse phase.
Perform processing. A detailed description will be given later. Then the processing circuit
A low-pass filter 116 suitable for the transmission rate of the output of 115
Remove unnecessary high frequency components through This digital code
With 90-degree phase shift through the transfer unit 117
Modulation of the signal carrier for digitally encoded audio signals
Modulates the signal with the Nyquist filter of the video reception IF
The frequency characteristics are corrected by an equalizer 119 having
The arithmetic unit 120 adds the carrier wave modulated with the video signal. So
As a result, the carrier for video is
The modulated audio signal is modulated in an orthogonal relationship.   According to the present embodiment, the phases are opposite in the adjacent horizontal scanning periods.
Since a single signal is transmitted as a multiplex signal, interference with video signals
There is an effect that can be reduced.   The spectrum to be modulated is shown in FIG.
Modulation between video signal and digitally encoded audio signal
3 is shown in FIG.   201 in FIG. 2 is the spectrum of the video signal after the VSB filter.
202, the spectrum of the FM-modulated audio signal, 203
4 shows the spectrum of a digitally encoded audio signal. 204
Will be described later. Where the video signal spectrum
201 and the spectrum 203 of the digitally encoded speech signal
Are shown in two stages in FIG. 2 because they are multiplexed orthogonally.
In the spectrum of a digitally encoded audio signal,
The effect of the equalizer 119 is not taken into account.   In Fig. 2, -0.75 MHz or less with respect to the video carrier
VS is assumed to be the residual sideband amplitude modulation
Attenuated by B filter. Video up to 4.2 MHz
The frequency spectrum modulated by the signal is 4.5 MHz
In the vicinity, there is a spectrum where the voice carrier is FM modulated
doing. Both for ± 0.75 MHz for video carrier
Considered as general amplitude modulation (DSB) because sidebands are transmitted
Good Orthogonal to the carrier that has both sidebands
Signals within ± 0.75 MHz are equivalent to digital codes 1 and 0
And modulated with amplitudes A and −A, the carrier vector
Is when the amplitude of the video carrier is 1   cosωct ± Asinωct (1) Becomes Here, ωc is the angular frequency of the carrier.   This is shown in FIG. Expanding equation (1) It is.   Digitally encoded to the received video signal here
Consider interference from audio signals. Video signal detection circuit is cos
For those that are synchronously detected at ω ct,
However, only the coefficient of cosωct (that is, only the video signal)
Is reproduced and does not disturb. Also, the video signal detection circuit
For those with envelope detection, set the value of A below 1
Interference can be reduced. For example, let A be 0.1
When, And compared to 1 0.005 signal (about -40dB) affects,
It is considered that there is no practical problem if the ratio is 40 dB or more.   On the other hand, interference from video signals to digitally encoded audio
Harm is demodulated by the synchronous detection circuit only for the component orthogonal to the carrier.
Can be eliminated. Signal level to noise ratio (hereinafter SN
Ratio), the S / N ratio of the video signal is 40dB
At a practical level, the bandwidth is digitally encoded sound
Since the transmission bandwidth of voice signals is about four times that of 1 MHz,
The S / N ratio of the digitally coded audio signal is 46 dB,
If the adjustment level A is 0.1, the transmission SN ratio is about 26 dB.
Also, the SNR of the digital signal and the bit error rate
When the SN ratio is 17.4dB even if the relationship is considered as a general binary signal
Ten^-FourIt is. If the S / N ratio of the video signal is 40 dB,
The transmission signal-to-noise ratio of a coded audio signal is 26 dB,
This is a practically sufficient value for transmitting a total signal.   Next, the digitally encoded speech signal spectrum 203
And the ternary conversion circuit 114. Digital code
The spectrum 203 of the converted audio signal is as shown in FIG.
It is assumed that the spectrum near the carrier frequency is suppressed.
This is the baseband digit before modulation by modulator 118.
Can be realized by suppressing the low-frequency component of the
The conversion circuit 114 converts a binary digital signal into a ternary signal.
With this, low-frequency components can be suppressed without reducing the transmission capacity.
There is an effect that can be.   FIG. 4 shows a ternary conversion circuit 114 having the function described above.
This is an example. 401 is binary digital data input, 402, 40
3,404 is an inverter, 405,406 is an AND circuit, 407 is an invar
Data, 408 is an adder, 409 is ternary digital data output, 41
0 is clock input terminal, 411 and 412 are D flip-flops
It is. The operation of FIG. 4 is compared with the timing chart of FIG.
It will be described using FIG. In FIG. 5, (a) is a binary digit
Data waveform, (b) is a clock signal, (c) is D-
Output of flip-flop 411, (d) is D-flip flow
412 outputs, (e) AND circuit 405 outputs, (f) AND times
406 output, (g) inverter 407 output, (h) ternary
It is a digital data waveform (output of the adder 408).
(A) The binary digital data shown in FIG.
First, only T / 2 which is half of one data length T
Delay (see FIG. 5 (c)), and then the D-flip
Delay by T / 2 which is half of one data length due to loop 412
As a result, the output of the D-flip-flop 412 is a binary data
Digital data input 401 than binary digital data
The signal is delayed by one data length T (FIG. 5).
(D)). Binary digital data by AND circuit 405
(A) and inversion of the output (d) of the D-flip-flop 412
Of the binary digital data (a)
Edge is detected as shown in FIG. Similarly, AND circuit 4
Inversion of binary digital data and D-flip at 06
Binary digital data by ANDing 412 output (d)
(A) Falling edge (f)
This is inverted by the inverter 407 to obtain the waveform shown in FIG.
The adder 408 adds the waveform shown in (e) and the waveform shown in (g).
Then, it becomes the ternary digital data shown in FIG.
Comparing the figures (a) and (h), the ternary digital data
Is high at the rising edge of binary digital data
(+1), Low (-1) pulse at falling edge
Generated with a pulse width of 1 data length T, otherwise High and Low
It can be seen that the intermediate potential (0) is obtained. like this
Converts binary digital data to ternary digital data
To reduce the baseband digital signal
Can be suppressed.
Modulation for digitally encoded audio signal, removed at 16
The frequency around the carrier frequency is modulated by the modulator 118.
Of Digitally Encoded Speech Signal with Suppressed Torque
Tol 203 is obtained. According to the ternary conversion circuit of FIG.
To reduce the transmission capacity when the transmission bandwidth is considered constant
Low-frequency components can be suppressed without any
The fundamental component of digital data has a relatively low frequency
Therefore, the baseband bandwidth becomes narrow, and as a result,
This has the effect of narrowing the transmission bandwidth. 1 and FIG.
Reduces frequency components near video carrier by circuit configuration shown
There is an effect that can be.   Next, frequency components near the carrier are reduced by the circuit configuration of FIG.
The effect when the amount is reduced will be described.   Fig. 204 shows carrier recovery in the case of carrier recovery type detection.
Carrier frequency selection of the carrier frequency selection circuit that constitutes the circuit
Selected band or carrier recovery for PLL synchronous detection
This represents the frequency response band of the PLL that constitutes the circuit. Within band 204
If the signal contains a signal other than the carrier frequency component,
These interfere with carrier recovery and degrade video detection characteristics.
Cause Digitally encoded speech signal spectrum
Since the vector 203 becomes this interference component, the band of the response band 204
Hopefully more spectral components in the region will be suppressed
New   Note that the video color subcarrier of the current television broadcast is
This will be discussed in detail later. in this way,
Carrying spectrum 203 of digitally encoded speech signal
Carrier frequency within the band where the spectrum near the wave frequency is suppressed.
By selecting the wave number selection band or PLL frequency response band
From orthogonally multiplexed digitally encoded speech signals.
It has the effect of reducing harm.   Here, one embodiment of the processing circuit 115 of FIG. 1 is shown in FIG.
Show. FIG. 7 shows the operation of FIG. 6 and the transmission of the present invention.
An example of a transmission data string is shown. 601 is the input terminal, 602 is the time axis pressure
Compression circuit, 603 is a timing generation circuit, 604 is an inverter,
605 is a delay circuit, 606 is a changeover switch, 607 is an output terminal, 7
01 is the data string of the input terminal 601, 702 is the time axis compression circuit 602
The output data string 703 is connected to the inverter 604 and the delay circuit 605.
The output data string of the delayed delay circuit 605, 704 is the transmission data of the present invention.
705 is a timing waveform.   Here, the signal input to the input terminal 601 is a ternary signal.
The block diagram shown in FIG.
Ternary digital circuit composed of
A digital circuit).
For example, if a ternary signal is represented by +1, 0, -1, the inverter 604
Converts +1 to -1, -1 to +1 and 0 to 0
Shall be. In addition, the data strings shown in FIGS.
This is a ternary signal.   The data string 701 applied to the input terminal 601 is generated at the timing.
The time axis compression circuit 602 decodes the data according to the timing of the raw circuit 603.
The data is compressed on the time axis and the intermittent data
I do. The intermittent data is transferred to inverter 604 and delay circuit 6
At 05, the data is inverted and only the delay time τ,
In the example shown in the figure, a delay of 5 data is shown in the data column 703.
Become like Switch between data string 703 and data string 702
When added by the switch 606, it becomes as shown in the data string 704. This
Data column 704 is inverted during the period when there is no data in data column 702
This means that the same data that has been entered is delayed. 8th
The figure shows an example of the transmission pattern of the present invention. Image delay time τ
And the timing waveform 705 is the same as the horizontal scanning period of
It shall be synchronized with the horizontal synchronization signal of the vision receiver.
Simulate the data transmission timing according to the television screen.
It is a fake one. Horizontal scanning in Fig. 8
The vertical direction indicates the vertical scanning direction. In the first horizontal scanning period
a₁From a_FiveTime series data until the second horizontal scanning period
The data from ▲ ▼ to ▲ ▼ will be the first and
In two horizontal scanning periods, the same data of opposite phases is obtained.   Also, here, the video color subcarrier of the current television broadcast
think about. FIG. 9 shows the color subcarriers on the video carrier.
FIG. (A) shows that there are many orthogonal components of the video carrier.
(B) shows the case where there is multiplexing to the orthogonal component
Show. ω_SDenotes the phase rotation on the color subcarrier, ω_SAnd ω
_S′ Indicates that the phase of the color subcarrier due to the adjacent horizontal scanning period is not π
Has been shown. l to s are vectors of the color subcarrier
1 to s and l 'to s' indicate color sub-transport.
This shows that the phases of the waves are shifted by π. A and
-A indicates a multiplexed signal into orthogonal components, and at some point adjacent water
The case where A and -A are set in the horizontal scanning period is shown. Current television
Frequency and horizontal scanning frequency in color broadcasting
From the relationship, the color subcarriers are l, m, n,
o…, s and l ′, m ′, n ′, o ′…, s ′
is shifted by π. As shown in FIG. 9 (b),
When multiplexing is performed, as shown in FIG.
Phase fluctuations, and the television video signal detection
In case of line detection, in case of multiplexing of A, color sub-carrier between s and l
Maximum amplitude position when the maximum amplitude of the wave appears and there is no orthogonal component
A phase difference φ from the phase 1 occurs. The phase variation of the color subcarrier is
It appears as a hue change on the playback video screen. This phase variation
Is cosω c in the figure when the video signal detection method is the synchronous detection method.
Since only the t-direction component is detected, even if A is multiplexed,
The maximum amplitude phase of the carrier is 1, and no phase fluctuation occurs.
No. In the case of envelope detection, π / 2 and −
The orthogonal components are multiplexed in π / 2 (indicated by A and -A in FIG. 9).
The phase direction of the maximum amplitude of the color subcarrier (the phase advance and
Delay) is determined, and the phase variation is caused by the absolute values of A and -A.
The amount is determined. The phase of the multiplex signal is changed between adjacent horizontal scanning periods.
When A and -A are set, ω becomes as shown in FIG._SAnd ω
_S'And the phase fluctuation amount is the same.
Therefore, the screen of the same signal in the adjacent horizontal scanning period
Hue change is reversed and frequency characteristics of human visual chromaticity sensitivity
(Eye integration effect), etc.
You. That is, a in FIG.₁~ A_FiveAnd ▲ ▼ ~ ▲
▼, b₁~ B_FiveAnd the same data like ▲ ▼ ~ ▲ ▼
The multiplex signal is A during the horizontal scanning period including the reverse phase of the data.
And -A, so the hue changes.
hard. However, ▲ ▼ ~ ▲ ▼, b₁~ B_FiveSame as
The hue changes during the horizontal scanning period when the data is not in reverse phase.
Easy to feel.   Further, in a television receiver, the horizontal scanning period
Brightness of "comb filter" of correlation (so-called line correlation)
Color sub-conveyance in the receiver used to separate the degree signal and color signal
The phase fluctuation of the wave can be canceled out in a circuit. Fig. 10 (a) shows one
Combined color signal extraction for general luminance signal and color signal separation
FIG. 3B is a configuration diagram of the filter, and FIG.
Show. 101 is an input terminal, 102 is a delay circuit, 103 is a subtractor, 1
04 is an output terminal, and 105 to 108 are waveforms of color subcarriers. Ten
5 is the case where there is no multiplexing, 106 is the right side of FIG.
On the left side of FIG. 9B, 108 is the reverse of 107. Multiplex
In this case, the color subcarrier is set to the time l corresponding to FIG. 9 (a).
Are shown by the maximum amplitude waveform 105. Here, the multiplexed signal of A is added.
In other words, the maximum amplitude appears between s and l, and the waveform 106
You. In the next adjacent horizontal scanning period, the multiplex signal of -A is added.
Ω_S′ Color subcarrier has a maximum amplitude between p ′ and q ′
The phases appear, resulting in waveform 107. One level through delay circuit 102
The waveforms 106 and 107 delayed by the scanning period are added to the subtractor 103.
Can be Waveform 108 shows the inversion of waveform 107.
Subtracting waveform 107 from waveform adds waveform 108 to waveform 106
When the amplitude is further reduced by half, a waveform 105 is obtained.
This waveform 105 is obtained from the output terminal 104. This comb-shaped
The chrominance subcarrier obtained by the filter is
Even if the multiplexed signal is added by the envelope detection method,
Indicates no change. Also in this case, FIG.
A shown₁~ A_FiveAnd horizontal running like ▲ ▼ ~ ▲ ▼
Horizontal scanning period when the upper and lower data are in opposite phases during the inspection period
Only one horizontal period
A horizontal scanning period that is not affected by phase fluctuations appears every scanning period.
It is.   As shown above, the book shown in FIGS. 6 to 8 in addition to FIG.
According to an embodiment of the present invention, the phase is reversed every one horizontal scanning period.
Since the multiplex signal is multiplexed, the hue change of the image due to the multiplex signal
Has the effect of reducing the interference on   In FIG. 6, the input data is continuous data.
Therefore, the time axis compression circuit 602 was used, but the input data was intermittent.
It may not be necessary in the case of typical discontinuous data.   Next, another embodiment of the processing circuit 115 of FIG. 1 is shown in FIG.
Show. FIG. 12 shows the operation of the transmission data sequence example of the present invention.
FIG. 13 is a diagram for explanation, and FIG. 13 is a simulation of transmission data of the present invention.
It is a pattern example. 1101 is input terminal, 1102 is invar
Data, 1103 is a delay circuit, 1104 is a timing generation circuit, 1105
Is a changeover switch, 1106 is an output terminal, 1201 and 1206 are
The timing waveform in the timing generation circuit 1104, and 1202 is the input data
1203, the output data string of the delay circuit 1103, and 1204, the data string.
Output timing waveform of imming generation circuit 1104, 1205
5 is an example of a transmission data string of the present invention.   Here, the signal input to the input terminal 1101 is a ternary signal
Yes, the block diagram shown in FIG.
It is a state digital circuit. See Fig. 12 and Fig. 13.
The data example is also a ternary signal.   The data string 1202 applied to the input terminal 1101 is
The data is delayed by time τ in the delay circuit 1103 via the line 1102.
Data row 1203 is obtained. Note that the timing waveform 1201 has a time τ
Invert every time. Timing waveform 1204 is the data in the data stream.
Data switch, and the switch 11
05 touches the (a) side and touches the (b) side when it is on the lower side. this
With the changeover switch 1105 controlled by the timing waveform 1204
Thus, a data string 1205 is obtained at the output terminal 1106.   The timing waveform 1206 is used as a horizontal synchronizing signal,
A diagram showing the data string 1205 in a simulated manner according to the
FIG. 13 is a diagram. Horizontal scanning direction vertically and vertical scanning direction vertically
Show. As shown by the circled frame in FIG.
In the scanning period, the upper and lower sides are inverted data for each data.
Has become. Data is inverted in the adjacent horizontal scanning period
This means that the multiplexed signal to the orthogonal component of the video carrier is inverted.
This indicates that there is a phase relationship, and the hue change of the image due to the multiplex signal.
The effect of reducing the disturbance to the structure is explained in FIGS. 9 and 10.
Is the same as   As described above, the embodiment shown in FIGS. 11 to 13 in addition to FIG.
If the multiplex signals in adjacent horizontal scanning periods are in opposite phases
Therefore, the effect of reducing the interference on the hue change of the image
There is. In addition, during one horizontal scanning period, one data
Cancels hue change by having opposite phase relationship with adjacent scanning period for each data
Changes to a hue as shown in the circle in Fig. 13
Interference with the visual chromaticity sensitivity frequency
The hue change of the image further than in the case of Figs.
This has the effect of reducing interference with the formation.   In the above embodiment, one horizontal scanning period is used as a transmission data string.
Fig. 7 shows the case of odd data in the example of 7 data.
In the case of data, 6 data are shown in FIGS. 14th
The figure shows a further embodiment of the processing circuit 115 of FIG.
FIG. 15 is a diagram for explaining the operation such as an example of a transmission data string, and FIG.
FIG. 16 is an example of a simulation pattern of transmission data according to the present invention. 11
04 is a timing generation circuit, 1401 is a timing input terminal,
1402 is timing generator, 1501,1504,1507 is timing
The timing waveform in the generation circuit 1104, 1502 is the input terminal 11
Input data string of 01, 1503 is output data of delay circuit 1103
Column, 1505 is the timing wave output from the timing generation circuit 1104
1506 is an embodiment of the transmission data stream of the present invention, and 1403 is
This is the exclusive OR (hereinafter abbreviated as EOR). Other
The same reference numerals as those in FIG. 11 indicate the same functions.   Here, the data strings shown in FIGS. 15 and 16 are ternary signals.
You.   11 is different from FIG. 11 in the timing generator 1104.
Provide a lure or 1403 and add timing waveforms 1501 and 1504
The timing waveform 15 is applied to the output of the timing generation circuit 1104.
05 is to control the changeover switch 1105. EO
R1403 controls the switch 1105 every horizontal scanning period
The timing is reversed, and a transmission data sequence 1506 is obtained.
The transmission data television shown schematically in FIG.
It becomes a pattern on the screen.   In the above embodiment as well, as in FIGS.
Has the effect of reducing interference with hue changes in
You.   The reception of the present invention for receiving the signal transmitted in the above embodiment.
One embodiment of the machine is shown in FIG.   1701 is an antenna, 1702 is a high frequency amplifier circuit, 1703 is a frequency
Number conversion circuit, 1704 is a reproduction IF filter for receiver, 1705 is
Intermediate frequency amplification circuit, 1706 is video signal detection circuit, 1707 is video
Image signal amplifying circuit, 1708: color difference signal demodulation circuit, 1709: primary color
Signal demodulation circuit, 1710 is CRT, 1711 is audio intermediate frequency
Amplification circuit, 1712 is audio FM detection circuit, 1713 is audio signal output
Terminal, 1714 is a band pass filter, 1715 is a synchronous detection circuit,
1716 is carrier recovery circuit, 1717 is delay circuit, 1718 is subtraction
, 1719 is a ternary identification circuit, 1720 is a code identification circuit, 1721 is
Clock recovery circuit, 1722 is switch, 1723 is time base extension
Circuit, 1724 is a timing recovery circuit, 1725 is a binary conversion circuit
Path, 1726 is digital signal processing circuit, 1727 is digital
・ Analog conversion circuit (hereinafter abbreviated as DAC), 1728 is digital
Output terminal for demodulated audio signals
You.   High frequency television signal input from antenna 1701
The signal is amplified by the amplifier circuit 1702 and demodulated by the frequency conversion circuit 1703.
Frequency conversion to intermediate frequency and regenerative IF filter for receiver 17
The signal is amplified by the intermediate frequency amplifier circuit 1705 via the line 04. Tuning is lap
This is achieved by changing the local oscillation frequency of the wave number conversion circuit 1703.
Will be The image from the signal amplified by the IF amplifier 1705
The image signal band is detected by the video signal detection circuit 1706,
Luminance signal and chrominance signal demodulation of output of video signal amplifier circuit 1707
The primary color signal demodulation circuit 1709 is obtained from the color difference signal output from the circuit 1708.
Then, the three primary colors of R, G and B are obtained and projected on the cathode ray tube 1710.   On the other hand, for the audio signal band,
The signal is amplified by the channel 1711 and detected and demodulated by the audio FM detection circuit 1712.
A voice signal is obtained at a voice signal output terminal 1713. The above is the conventional text
Same as the revision receiver.   In addition to the above, demodulate digitally encoded audio signals
The output of the frequency conversion circuit 1703 to the bandpass filter.
Digitally encoded sound multiplexed by router 1714
Select and amplify the voice signal band, and use the synchronous detection circuit 1715
And synchronized with the carrier reproduced by the carrier regeneration circuit 1716
The signal is used to change the amplitude of the
The modulated signal is detected and demodulated.   The demodulated waveform is delayed by one horizontal period via delay unit 1717.
The subtracted 1717 subtracts the demodulated waveform. Subtracting
The transmitted data is doubled and the white noise is Only increase. In addition, for horizontal periods such as image ghosts
Interference from an image having a lot of correlation with can be canceled out.
The signal obtained by the subtractor 1718 is +1,0,
-1. This ternary digital signal
Using a code identification circuit 1720 and a clock recovery circuit 1721
Low error rate (the so-called maximum aperture of the eye pattern)
Section) to digital code. Digitally encoded
Switch 1722 and timing only for necessary data among signals
Select and take out by the reproduction circuit 1724, and the time axis expansion circuit 1723
To return to the original data transmission rate. Then ternary digit
Binary signal of +1 and 0 by the binary conversion circuit 1725
Signal, and transmitted by the digital signal processing circuit 1726 during transmission.
The generated error is detected and corrected using the error detection and correction code.
The digital signal after error detection and correction is processed by DAC1727.
Converted to analog signal and converted back to audio signal, digital code
The demodulated output 1728 of the converted audio signal is obtained.   The removal of interference from video signals is performed in the following process.
Be done. X at a certain timing in a certain horizontal scanning period
When sending data, the next horizontal run is delayed by one horizontal period.
The same data at the same timing as the inspection period
X inverted data is sent. Receiver delay unit17
17 and the subtractor 1718, X received one horizontal scanning period ago and
Received in the next horizontal scanning period, but subtracted at the same timing
So   X-() = 2X Thus, a double signal is obtained. During this transmission,
The video signal is scanned horizontally
For images that have a lot of correlations by period (images such as vertical stripes)
At the timing of X and at the timing of G
The Rukoto. By subtractor 1718,   (X + G)-(+ G) = 2X And the interference from the video is canceled. However,
If the correlation between the horizontal scanning periods of the signal is small,
Less.   According to the reception example described above, the carrier recovery circuit 1716
The carrier frequency selection band or the PLL response frequency band is
Because the spectrum of the multiplex signal is within the band where it is suppressed
Can receive quadrature multiplexed signals stably and further interfere with video
This has the effect of reducing   Next, the ternary conversion circuit 114 and the processing circuit 115 shown in FIG.
Realization in the case of using binary digital elements (TTL, CMOS, etc.)
Examples are shown in FIGS. 18, 19, 20, and 21. FIG.   FIG. 18 shows an embodiment of the ternary conversion circuit of FIG.
Same as the embodiment shown in FIG.
It shows the function. 1801 is binary digital data input
1802A is the edge detection circuit and 1802A is the rising edge.
1802B is a falling edge detection circuit, 1803 is
Time axis compression circuit, 1804 is delay circuit, 1805 is switch
H, 1806 is an inverter, 1807 is an addition circuit, and 1808 is
Circuit. A and B of 1803 to 1804 stand
Rising edge detection circuit 1802A, falling edge detection circuit 1
Indicates that the output of the 802B is to be processed, and the functions are the same.
Selector switch 1805 has both rising and falling edges
A and B mean that the functions are the same to handle signals.
Do not have.   Operation of FIG. 18 is a timing chart of FIGS. 5 and 7.
This will be described with reference to FIG. The binary digital data shown in FIG.
Data waveform is input from binary digital data input 1801
And rising edge detection circuit 1802A, falling edge detection
By the circuit 1802B, as shown in FIGS. 5 (e) and (f), respectively.
An edge is detected as follows.   As can be seen, the ternary conversion circuit shown in FIG.
The output of the AND circuit 405 and the output of the AND circuit 406 of the embodiment are respectively
Outputs rising edge and falling edge. Edge detection
When the output circuits 1802A and 1802 are divided for each data length T,
Each data string can be considered as shown in FIG.
Now, for the sake of explanation, the output of the rising edge detection circuit 1802A
A is added to the number of the data string of the system that processes
Of the data string of the system that processes the output of the edge detection circuit 1802B
With the subscript B. Data strings 701A and B
Time axis compression circuit 18 according to the timing of the
03A and B compress the data on the time axis and
The data strings 702A and 702B are obtained by the ming. Selector switch 1805A, B
If the switches are closed toward (a), the switch
The signal 702A on the rising edge side is switched to the output of switch 1805B.
The signal 702B on the falling edge side is output from the switch 1805A.
Selected. Selector switch 1805A output is inverter 1806
And the output of the switch 1805B by the adder circuit 1807.
The addition results in a ternary signal at the output of the addition circuit 1807. This dynamic
The operation will be described with reference to the time chart of FIG. Fig. 5
(E) Time-axis compression of the rising edge circuit 1802A output
The waveform compressed by the path 1803A, (f) is the falling edge circuit 1
Waveform compressed 802B output by time axis compression circuit 1803B,
(G) is an inverted signal of (f), and (h) is the inverted signal of (e) and (g).
A ternary signal obtained by adding waveforms, (i) is the inverse of (e)
(J) is obtained by adding the waveforms of (f) and (i).
This is a ternary signal. Here, T is 1 d after compression.
Indicates the data length. The changeover switch 1805 is closed toward (a)
Switch, the switch (1805B) turns off the waveform (e).
Switch 1805A outputs the waveform of (f)
The output of the data 1806 has a waveform (g). Therefore the addition circuit
The 1807 output becomes a ternary signal as shown in (h) and a data string
702 is output. Next, switch 1805 is (b)
When the switch is closed to
The waveform (e) is output to the changeover switch 1805A.
The output of the inverter 1806 has the waveform (i). Accordingly
The output of the adder 1807 becomes the waveform of (j) and the waveform of (h)
Are the three types of signals that are inverted with respect to the middle point potential center. However
Delay when switch 1805 is closed toward (b)
Delay through the circuit 1804 with a delay time τ,
In the example of the figure, the ternary signal (j) is delayed by 5 data and the ternary signal (j) is a data string.
As shown in 703. Therefore, the output of the adder 1807 is
The result is as shown in FIG. This data sequence 704 is shown in FIG.
Is the same as the circuit output. According to the embodiment of FIG.
It is possible to process ternary signals using value digital elements.
There is a clear effect.   FIG. 19 also shows a fourth ternary conversion circuit embodiment and a tri-state converter.
G The same machine as the embodiment of FIG.
It shows the performance.   1901 is a time axis compression circuit, 1902 is an edge detection circuit
1902A is the rising edge detection circuit, 1902B is the falling edge detection circuit.
This is a digital detection circuit. The example in Fig. 19 is a binary digital data
Data on the time axis, and edge
It performs detection. Therefore 1902 edge detection
Is the pulse width of one data length interval after compression. Fig. 19
Has the effect that only one time axis compression circuit is required.   FIG. 20 shows an embodiment of the ternary conversion circuit of FIG.
Same as the embodiment of FIG.
Indicates the function. 2001 is a timing generation circuit. Fig. 20
The operation shown in FIG.
Edge detection circuit 1802A output, falling edge detection circuit 1802B output
The delay time τ of the delay circuit 1804 is shown in FIG.
And the timing of switching the switch 1805
Fig. 1224 and its high level (b) side, low level
In the case of, close to (a) side. In this timing waveform 1204
Data string 1205 ternary by controlled switch 1805
It is obtained at the output terminal 1809 as a signal. In the embodiment of FIG.
According to this, it is possible to obtain a ternary signal using a binary digital element.
There is an effect that can be.   FIG. 21 shows an embodiment of the ternary conversion circuit shown in FIG.
Same as the embodiment shown in FIG.
Indicates the function. 2101 is the timing input terminal, 2102 is the timing
The ringing generator 2103 is an EOR.   The difference from Fig. 20 is the timing generation circuit.2001Within EOR2103
The timing waveform shown in Fig. 15
Generator2001Output the timing waveform 1505 to
To control the replacement switch 1805. Embodiment of FIG. 21
Obtains a ternary signal using a binary digital element.
There is an effect that can be.   As can be seen from the above description, the same multiplex signal is output twice in opposite phase.
By taking the form of transmission, interference can be reduced, but on the other hand, multiplexing
If the signal transmission band is fixed, the transmission capacity is reduced by half.
And multi-valued systems with four or more values, and duo-binary codes
Compression of transmission bandwidth by actively utilizing intersymbol interference such as signals
Improvement by partial response method that performs
It is also possible. In addition, partial response method
For the ceremony, see Ohmsha's modern digital
The details are shown on pages 137 to 142 of the
Details are omitted.   Also, in FIGS. 8, 13, and 16, the television video signal
Simultaneously shows the modulation method of the multiplex signal corresponding to the screen of
Was. In these cases, the multiplex signal has a constant
Although explained with the number of synchronized signals, the transmission speed of multiplexed signals
If the horizontal scanning period is not synchronized with the
Horizontal scanning period and the horizontal scanning period of the video signal almost match
The same effect of reducing interference to video signals.
You. The last data time of the horizontal scanning period is optional.
Increase or decrease the number of data in a pair of horizontal scanning periods.
Can also be absorbed.   Indicates the number of increase / decrease of this data number and its horizontal scanning period
If the control signal or the top multiplex signal in the horizontal scanning period is up or down
The same signal in opposite phase to the multiplexed signal in either of the adjacent scanning periods
Control signal or the vertical scan period
Of the present invention to transmit the control signal shown in addition to the multiplex signal.
Another embodiment is shown in FIG. 2201 is for timing generation
Control circuit, 2202 is a control signal generation circuit, 2203 is a changeover switch
And the same reference numerals as those in FIG. 1 indicate the same functions. Digital
Output and control signals of the signal processing circuit 113 and the processing circuit 115
The output of the generation circuit 2202 is
By switching the changeover switch 2203 at the timing, the control signal and
Time division multiplexing with data from digital signal processing circuit
You. Note that only during the period of the control signal (switch 2203
Only when it is in contact with the control signal generation circuit 2202)
Data transmission is not possible, so digital signal processing
The output of the processing circuit 113 or the processing circuit 115 is stopped. Ma
Also, in order to prevent the data during the suspension period from being discontinuous,
Digital signal processing circuit 113 or processing circuit 115
Before performing time axis compression of data, for control signals etc.
Intermittent data with a gap in time. Many of the results
An example of a double signal is shown in FIG. 2301 is vertical sync signal, 2302
Indicates a horizontal synchronization signal, 2303 indicates a multiplex signal, and 2304 indicates a multiplex signal.
This is an intermittent expansion signal. In this example, TV horizontal sync
It is shown according to the signal. Vertical synchronization of horizontal synchronization signal 2302
C in the next horizontal scanning period following the equalization pulse period after the
16 bits of synchronization signal, 32 bits of control signal,
48 bits in the opposite phase during the next horizontal scanning period (indicated by
This is an example of the addition. This control signal period is defined as two vertical periods
Two times, in the case of current Japanese television
Is a control signal for one horizontal scanning period out of 525 horizontal scanning periods.
The output of the processing circuit 115 is 525/523 times
Data may be compressed on the time axis.   According to the present embodiment, the adjacent horizontal scanning period of the horizontal scanning period
Multiplex signal polarity, horizontal scanning period number, horizontal scanning period
Of the transmission capacity of the multiplexed signal, and the increased or decreased horizontal scanning period
Since control signals such as inter-numbers can be multiplexed,
Easy and stable operation of signal processing for receivers that receive signals
There is an effect that can be made.   Next, the interface of the digital signal processing circuit 113 of the present invention is described.
The example of a leave process is shown. Fig. 24 shows television such as Fig. 16
FIG. 3 is a transmission pattern diagram schematically shown corresponding to a screen.
The left channel of the sampled audio signal.
L for each ring₀, L₁, L_TwoRight channel R₀, R₁, R_Two
Indicated by ▲ ▼, ▲ ▼, ▲ ▼, ▲ ▼, ▲
▼ and ▲ ▼ are L₀, L₁, L_Two, R₀, R₁, R_Two, Inverted data
And transmitted in adjacent horizontal scanning periods. In this diagram, L₁To
L for_Two, L₀Data at adjacent sampling points
Inserting (interleaving) more than flat scan period
This is the feature.   According to the present embodiment, data at adjacent sampling points
Since they are inserted at a distance of more than the horizontal scanning period,
As described, the image with little correlation between adjacent horizontal scanning periods
For images (videos with a large difference between adjacent horizontal periods),
Suppose that the signal that was delayed by one horizontal scanning period was subtracted by
Even if the interference from the video signal cannot be sufficiently canceled,
Incorrect data during scanning period, signal at a certain sampling point
Data at adjacent sampling points
Interleaving eliminates errors during the same horizontal scanning period
Since it exists in other horizontal scanning periods, interference from the video signal
Sampling with errors because they are offset and hard to cause errors
It is safe to interpolate the signal at a point from adjacent sampling points.
There is an effect that a constant multiplex signal can be reproduced.   The reception of the present invention for receiving the signal transmitted in the above embodiment.
One embodiment of the machine is shown in FIG. 2501 is the control signal reproduction time
The reference numeral 2502 denotes an interpolation control circuit, which has the same reference numerals as those in FIG.
Indicates the same function. Coded by control signal reproduction circuit 2501
The control signal is obtained from the digital code output from the identification circuit 1720.
And a timing reproduction circuit 1724 according to the control signal.
The necessary data is extracted by the switch 1722 via the
Then, the original continuous data is reproduced by the time axis expansion circuit 1723. De
The digital signal processing circuit 1726 detects errors that occur during transmission.
And correct the error and collect in areas with little correlation
A sump that cannot be corrected due to an intermediate error
The signal at the ring point is digitalized by the interpolation control circuit 2502.
The signal processing circuit 1726 is controlled to
Interpolated by calculating using average value interpolation or holding the previous value
Replace with a signal.   According to this embodiment, the reproduction by the control signal and the adjacent
Interpolation from the sampling point enables stable reception and reproduction
There is an effect that can be obtained. 〔The invention's effect〕   According to the invention, the orthogonal relationship with the amplitude-modulated carrier
Signals such as digitally encoded audio signals that are modulated
From the spectrum of the video signal near the carrier frequency
Carrier that is amplitude modulated because it can suppress torque
If the detection circuit of this type is carrier-wave recovery type detection,
Of the carrier frequency selection band of the selection circuit and the PLL synchronous detection circuit
In this case, the orthogonally multiplexed
Reduces interference from signals such as digitally encoded audio signals.
Slightly due to phase variations caused by orthogonal multiplex signals
This has the effect of reducing the accompanying hue change. Also, video
Wait for the orthogonal relationship with the carrier video signal, and
Phase relationship of the same multiplex signal during the horizontal scanning period
Can be multiplexed as
Multiplexing to video signal even if the detection method is the envelope detection method
This has the effect of reducing interference from signals.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a transmitter according to an embodiment of the present invention, FIG.
FIG. 3 is a spectrum diagram for explaining the present invention, FIG. 3 is a vector diagram for explaining the present invention, FIG. 4 is a block diagram for explaining a main part of the present invention, and FIG. FIG. 6 is a block diagram for explaining the main part of the present invention, FIG. 7 is a timing chart for explaining the operation of FIG. 6, and FIG. 8 is a screen pattern of a transmission signal according to the present invention. FIG. 9 is a vector diagram for explaining the present invention, FIG. 10 is a waveform diagram for explaining the present invention, FIG. 11 is a block diagram for explaining main parts of the present invention, and FIG. FIG. 11 is a timing chart for explaining the operation of FIG. 11, FIG. 13 is a screen pattern of the transmission signal of FIG. 11, FIG. 14 is a block diagram for explaining a main part of the present invention, and FIG. The timing diagram to be described, FIG. 16 is a screen pattern of the transmission signal of FIG. 14,
FIG. 17 is a block diagram of the receiving apparatus of the present invention, FIG. 18 is a block diagram for explaining main parts of the present invention, FIG. 19 is a block diagram for explaining main parts of the present invention, and FIG. FIG. 21 is a block diagram illustrating a main part of the present invention, FIG. 22 is a block diagram of a transmitter illustrating an embodiment of the present invention, and FIG. 23 is a waveform of a transmission signal of the present invention. Figure,
FIG. 24 is a schematic diagram of a screen pattern of a transmission signal of the present invention,
FIG. 25 is a block diagram of the receiving device of the present invention. 114 ternary conversion circuit, 115 processing circuit, 411, 412 D
A flip-flop, 408, an adder, 602, a time axis compression circuit, 603, a timing generation circuit, 605, a delay circuit, 606
... Changeover switch, 1103 Delay circuit, 1104 Timing generation circuit, 1105 Changeover switch, 1402 Timing generator, 1403 EOR, 1802 Edge detection circuit, 1803
Time axis compression circuit, 1804… Delay circuit, 1805… Changeover switch, 1805… Changeover switch, 1807… Addition circuit, 1808…
Timing generation circuit, 1901 …… Time axis compression circuit, 1902 ……
Edge detection circuit, 2102 Timing generator, 2103 EO
R, 2201 timing control control circuit, 2202 control signal generation circuit, 2203 changeover switch.

Continuation of the front page (72) Inventor Noritaka Hotta 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Within Hitachi Video Engineering Co., Ltd. (56) References JP-A-63-240281 (JP, A) JP-A-63-240282 ( JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04N 7/08

Claims (1)

(57) [Claims] In a transmission method for transmitting a residual sideband amplitude modulated wave by performing residual sideband amplitude modulation on a video carrier with a video signal,
A digitized multiplex signal different from the video signal is
Perform a spectrum suppression process to suppress the low frequency component, and further, the multiplexed signal subjected to the spectrum suppression process,
The horizontal scanning inverse correlation processing is performed to obtain the same data that is repeated in units of horizontal scanning periods of the video signal and is inverted at least at the same timing in two adjacent horizontal scanning periods into the opposite phase relationship. A multiplexed signal, wherein a quadrature carrier having a quadrature relationship with the video carrier is carrier-suppressed amplitude-modulated, combined with the residual sideband amplitude-modulated wave, and transmitted. 2. The horizontal scanning inverse correlation process includes a process of compressing a multiplexed signal on the time axis and repeatedly transmitting the time-axis-compressed signal in units of a horizontal scanning period of the video signal. 2. The multiplex transmission method according to claim 1. 3. The above-described spectrum suppression processing sets the rising edge data of the digitally encoded binary signal data to a high-level pulse with respect to the intermediate level, and sets the falling edge data to a low-level pulse with respect to the intermediate level.
3. The multiplex transmission method according to claim 1, wherein the other data is a ternary digital signal having an intermediate level. 4. 4. The multiplexed signal according to claim 1, wherein a control signal is provided for each predetermined period synchronized with a vertical scanning period of the video signal. Multiplex transmission method. 5. In a signal generator having an amplitude modulation circuit for modulating a video carrier with a residual sideband amplitude modulation signal with a video signal to generate a residual sideband amplitude modulated wave, a quadrature carrier is generated from a video carrier generation circuit for transmitting the video signal. A transfer unit, a spectrum band suppression circuit for reducing a frequency spectrum near a video carrier frequency of a digitized multiplex signal different from the video signal, and an output of the spectrum band suppression circuit as a unit of a horizontal scanning period of the video signal. And a horizontal scanning inverse correlation processing circuit for performing horizontal scanning inverse correlation processing so as to obtain the same data inverted to an inverse phase relationship at the same timing in at least two adjacent horizontal scanning periods, and the horizontal scanning inverse correlation processing circuit A modulating circuit for carrier-suppressing amplitude modulation of a quadrature carrier having a quadrature relationship with a video carrier which is an output of the transferer at the output; Signal generating apparatus characterized by the output and the vestigial sideband amplitude modulation wave of the modulation circuit is provided and a combining circuit for combining. 6. The spectrum band suppressing circuit includes a delay circuit that delays the binary data of the digitized multiplexed signal, a first inverting circuit that inverts the binary data of the digitized multiplexed signal, Second to invert the output
A first AND circuit for calculating the logical product of the binary data of the digitized multiplexed signal and the output of the second inverting circuit; the output of the delay circuit and the first inverting circuit A second AND circuit for ANDing the output of the circuit, a third inverting circuit for inverting the output of the second AND circuit, and an output of the first AND circuit and a third inverting circuit 6. The signal generator according to claim 5, further comprising an adder circuit for adding output of the circuit to obtain ternary data. 7. The horizontal scanning de-correlation processing circuit includes a horizontal scanning unit that delays the output of the digitized multiplexed signal from the spectrum band suppression circuit or the multiplexed signal output from the addition circuit in units of a horizontal scanning period of a video signal. 7. The signal generating device according to claim 5, further comprising a period delay circuit, and an inverting circuit for inverting the digitized multiplexed signal to a reverse phase. 8. 8. The horizontal scanning inverse correlation processing circuit according to claim 5, further comprising a time axis compression function for compressing the digitized multiplexed signal on a time axis.
A signal generator according to any of the preceding claims. 9. The horizontal scanning inverse correlation processing circuit has a control signal generating function of adding a control signal at regular intervals in synchronization with the vertical scanning period of the video signal in the digitized multiplexed signal. The signal generator according to any one of claims 5 to 8, wherein: