JP2002152158A - Ground digital tv broadcasting transmitting method and ground digital tv broadcasting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground digital TV broadcasting transmitting method and a ground digital TV broadcasting system, with which repeated transmitting is enabled while keeping sufficient performance as a while by holding high frequency accuracy, improving a transmitting quality as well and dealing with multi-stage repeating although there is a problem that the transmitting quality is deteriorated by superimposing phase noise in a conventional method. SOLUTION: In this ground digital TV broadcasting transmitting method, a receiving side frequency reference signal, a pilot carrier and a broadcasting wave IF signal are transmitted from a studio as a frequency-multiplexed STL signal and at a transmitting station, the frequency synchronization and noise removal of the broadcasting wave IF signal and a repeating wave IF signal are performed by using the receiving side frequency reference signal and the pilot carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a terrestrial digital TV.
More particularly, the present invention relates to a terrestrial digital TV broadcast transmission method and a terrestrial digital TV broadcast transmission system capable of relay transmission while maintaining sufficient performance by removing noise.

[0002]

2. Description of the Related Art At present, research and development of terrestrial digital TV broadcasting are being vigorously pursued for future realization. In terrestrial digital TV broadcasting, in order to expand the service area on a nationwide scale, it is essential to install a broadcast wave relay station that relays a broadcast wave transmitted from a master station and transmits the broadcast wave to a slave station.

[0003] At present, a broadcast wave relay station in analog terrestrial broadcasting uses a system in which a broadcast wave from a master station is converted into a frequency different from the transmission frequency of the master station and transmitted to a slave station. In terrestrial digital TV broadcasting, on the other hand, effective use of precious frequency resources is
In order to widen the area broadcast at the same frequency in a mobile service using V broadcast, the transmission frequency of the broadcast relay station is set to the same frequency as that of the master station, so-called SF.
Construction of N (Single Frequency Network) is an important issue.

When a network is constructed by the SFN method,
In the relay station, there is a problem that an oscillation phenomenon or the like due to the roundabout of the local station occurs, so that it becomes difficult to relay the broadcast wave, and it becomes impossible to transmit with a desired output.

[0005] To solve the problem caused by the wraparound, OFD used in terrestrial digital TV broadcasting has been proposed.
It is considered that an M (Orthogonal Frequency Division Multiple) signal is relayed to each relay station as it is to achieve effective use of frequency and cost reduction. However, if the OFDM signal is frequency-converted and transmitted as it is, even if there is a slight fluctuation in the local oscillation frequency on the side of the receiving device provided in each relay station, the OFDM signal can be transmitted.
Since a fatal obstacle is given to the demodulation of the DM signal, there has been a demand for the development of a technique capable of eliminating such fluctuations and reliably relaying the OFDM signal.

As one method for preventing fluctuations in the local oscillation frequency at each relay station, a technique using a pilot signal is disclosed in Japanese Patent Application Laid-Open No. H11-205280, published Jul. 30, 1999, entitled "Transmission Device and Receiving device "
(Applicant: Japan Broadcasting Corporation, Inventor: Yukio Tatsumi and others). According to this conventional technique, a pilot signal is superimposed on the upper side (or lower side) of a spectrum constituting an OFDM signal so as to have a frequency slightly apart from the spectrum of the OFDM signal, and is transmitted from a transmitting apparatus. The oscillation frequency of the local oscillator is controlled based on the pilot signal in the IF signal obtained by frequency-converting the transmission signal. This prevents fluctuations in the local frequency at each relay station. , OFDM signal can be reliably converted or demodulated, and effective use of frequency and cost reduction can be achieved.

[0007]

However, in the terrestrial digital TV broadcasting system using the above-mentioned conventional transmitting device and receiving device, it is possible to cancel the phase noise and the like superimposed during the relay transmission process, while maintaining the frequency accuracy. However, when the number of relays increases, phase noise and the like are superimposed one after another, deteriorating transmission quality.

[0008] The present invention has been made in view of the above-mentioned circumstances, while maintaining high frequency accuracy, improving transmission quality, and coping with multi-stage relay, while maintaining sufficient performance as a whole. Terrestrial digital T that can be relayed
It is an object to provide a V broadcast transmission method and a terrestrial digital TV broadcast system.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention relates to a method of transmitting digital terrestrial television broadcasting. FM reference signal obtained by FM-modulating a signal, pilot carrier and broadcast wave IF
Frequency multiplexing with a signal, frequency-converted and transmitted as an STL signal, a transmitting station receives an STL or a TTL signal from a preceding transmitting station, frequency-converts the signal, generates a reception IF signal, and Acquires the receiving-side frequency reference signal from the FM reference signal in the signal, performs frequency synchronization and noise reduction of the broadcast wave IF signal using the receiving-side frequency reference signal and the pilot carrier, and transmits it to the television receiver as a broadcast wave. At the same time, the reception IF signal is frequency-synchronized and denoised using the reception-side frequency reference signal and the pilot carrier to form a relay IF signal, and the relay IF signal is frequency-converted to a subsequent transmission station as a TTL signal. Since the relay transmission is used, the FM transmitted from the studio at each transmitting station
According to the receiving-side frequency reference signal obtained from the reference signal, frequency synchronization is performed with high precision, and further, while removing phase noise superimposed in the transmission process, while transmitting the broadcast IF signal, relay-transmitting the relay IF signal, While maintaining high frequency accuracy, transmission quality is also improved, and multi-stage relay can be supported, so that relay transmission can be performed while maintaining sufficient performance as a whole.

The present invention for solving the above-mentioned problems of the prior art is a digital terrestrial television broadcasting transmission system in which a studio performs FM modulation on a receiving-side frequency reference signal used for frequency synchronization and noise removal on the receiving side. A signal, a pilot carrier and a broadcast wave IF signal are frequency-multiplexed and then converted into a frequency and transmitted as an STL signal. The transmitting station receives the TTL signal from the STL or the preceding transmitting station, Generates a reception IF signal by performing frequency conversion, obtains a reception-side frequency reference signal from an FM reference signal in the reception IF signal, and uses the reception-side frequency reference signal and a pilot carrier to perform frequency synchronization and noise of a broadcast wave IF signal. The signal is removed, transmitted as a broadcast wave to the TV receiver, and the receiving side frequency reference signal and pilot
Since the carrier IF is used to perform frequency synchronization and noise removal of the received IF signal to form a relay IF signal, and to convert the frequency of the relay IF signal to a TTL signal for relay transmission to a subsequent transmitting station, each transmitting station is used. At the same time, while synchronizing the frequency with high precision according to the receiving side frequency reference signal obtained from the FM reference signal transmitted from the studio, and further removing the phase noise superimposed in the transmission process, transmitting the broadcast wave IF signal, The relay IF signal is relay-transmitted, and while maintaining high frequency accuracy, transmission quality is improved and multi-stage relay is supported, so that relay transmission can be performed while maintaining sufficient performance as a whole.

[0011]

Embodiments of the present invention will be described with reference to the drawings. Note that the function realizing means described below may be any circuit or device as long as the function can be realized, and some or all of the functions may be realized by software. is there. Further, the function realizing means may be realized by a plurality of circuits, or the plurality of function realizing means may be realized by a single circuit.

[0012] In general terms, the terrestrial digital TV broadcasting transmission method and the terrestrial digital TV broadcasting system according to the present invention provide a receiving side frequency reference signal used for frequency synchronization and noise removal at a receiving side in a studio. Modulated FM reference signal, pilot carrier and broadcast wave I
Frequency multiplexing with the F signal, frequency conversion and STL
The signal is transmitted as a signal, the transmitting station receives the STL or the TTL signal from the preceding transmitting station, converts the frequency, generates a receiving IF signal, and obtains the receiving-side frequency reference signal from the FM reference signal in the receiving IF signal. Then, frequency synchronization and noise removal of the broadcast wave IF signal are performed using the reception-side frequency reference signal and the pilot carrier, and the broadcast-wave IF signal is transmitted to a television receiver as broadcast radio waves.
The carrier IF is used to perform frequency synchronization and noise removal on the received IF signal to form a relay IF signal, and the relay IF signal is frequency-converted and relayed and transmitted as a TTL signal to a subsequent transmitting station. F transmitted from
Transmits the broadcast IF signal while relaying the relay IF signal while synchronizing the frequency with high accuracy in accordance with the receiving-side frequency reference signal obtained from the M reference signal and further removing the phase noise superimposed in the transmission process. In addition to maintaining high frequency accuracy, the transmission quality is also improved, and multi-stage relay can be supported, so that relay transmission can be performed while maintaining sufficient performance as a whole.

According to the function realizing means, in the digital TV broadcasting system according to the present invention, a modulator in a studio generates a broadcast wave IF signal by digitally modulating broadcast data using a high-precision reference signal. A modulator that outputs a broadcast wave IF signal and a reference signal, and the STL transmitter in the studio is:
Pilot carrier generation means for generating a pilot carrier used for frequency synchronization and noise removal on the reception side, and a reception side frequency reference signal used for frequency synchronization and noise removal on the reception side based on a reference signal from the modulator. A receiving-side frequency reference signal generating unit, an FM reference signal generating unit configured to generate a FM reference signal by performing broadband FM modulation on the receiving-side frequency reference signal, and a broadcast wave IF from the modulator
A STL transmitter having frequency multiplexing means for frequency-multiplexing a signal, a pilot carrier and an FM reference signal, and transmission frequency converting means for frequency-converting the frequency-multiplexed signal and transmitting a TTL signal, STL / TT
L receiver receives an STL signal from a studio or a TTL signal from a transmitting station at a preceding stage, converts the frequency, and
Receiving means for generating a signal, a component of a received IF signal, a component of a pilot carrier,
Frequency division division means for outputting a component of the reference signal;
Obtaining a receiving-side frequency reference signal from the component of the M reference signal;
A pilot carrier is reproduced from the pilot carrier component, and a broadcast IF signal is reproduced and output by performing frequency synchronization and noise removal of the broadcast IF signal in the received IF signal. Since the STL / TTL receiver has local noise canceling means for performing frequency synchronization and noise removal of a received IF signal using a carrier to reproduce and output a relay IF signal, each transmitting station In the STL / TTL receiver, the local noise canceling means performs frequency synchronization with high accuracy in accordance with the receiving-side frequency reference signal obtained from the FM reference signal transmitted from the studio, and further removes the phase noise superimposed in the transmission process. While removing the broadcast wave I
While transmitting the F signal and relaying the relay IF signal, it maintains high frequency accuracy, improves the transmission quality, and can cope with multi-stage relay. It can be transmitted.

The correspondence between each means in the embodiment of the present invention and each part in FIG. 2 or FIG. 4 is as follows. The receiving unit of the TTL transmitter corresponds to the receiving F / E unit 30 and the receiving IF unit 31 in FIG.

[0015] First, the STL /
The schematic configuration of a terrestrial digital TV broadcasting system that realizes the TTL transmission method will be described with reference to FIG. FIG.
1 is a schematic configuration block diagram of a digital terrestrial TV broadcast system according to an embodiment of the present invention. As shown in FIG. 1, the terrestrial digital TV broadcasting system according to the present embodiment includes a studio, a master station, a slave station / relay station (2), a slave station / relay station (3) (not shown), and a slave station. / Relay station (4) (not shown), slave station / relay station (5), and five television receivers (three of which are shown by TV-RX in the figure) 9 Have been. In the present invention, SFN (Single)
Frequency Network: In a single frequency network system,
The condition is that five wireless lines are continuously connected. Also, it is considered that the study of SFN is affected by the broadcast waves from the adjacent station and the next adjacent station. Also, S
The TL / TTL SFN shall not be considered.

Here, an STL (Studio to Transmitter) linking between the studio and the master station using microwaves.
Link) Single section communication, master station and slave / relay station (2)
And between the slave station and the relay station are TTL (Transmitter to Transmitter Link) single-section communication linking using microwaves. The frequencies f10, f21, f32,..., F54
Are STL / TTL frequencies for the A to G bands, and S
FN shall not be considered. Further, the frequencies f1-1 and f1-
2,..., F1-5 are SFN broadcast frequencies, which are the same frequency. Here, the number following "-" represents the transmitted transmitter.

Next, the internal configuration of each system in the system shown in FIG. 1 will be specifically described. The studio includes a studio BST-OFDM modulator (BST-OFDM MOD in the figure) 1 that digitally modulates captured video, audio, data, and the like into a broadcast IF signal, and a modulated broadcast IF signal. And an STL transmitter (in the figure, an STL-transmitter) that frequency-multiplexes various reference signals (FM reference signals and pilot carriers) used for frequency synchronization and noise removal (noise cancellation) on the receiving side and transmits the frequency-f10. T
X0) 2.

In the BST-OFDM modulator 1, the BST-OFDM
OFDM (Band Segmented Transmission-Orthogonal
Frequency Division Multiplexing (band division transmission-orthogonal frequency division multiplexing) is performed. Here, BST-OF
DM is a method devised to give OFDM more flexibility and expandability. OFDM prepares a very large number of carriers, and divides information into each one and digitally modulates the information. In addition to having a characteristic of being resistant to ghosts and the like, BST-OFDM has a characteristic of, for example, 100 kHz.
A small OFDM wave with a minimum unit of about z (this is BS
The basic idea is to configure a large number of BST segments and configure a transmitted radio wave using a required number of BST segments. In the drawings of the present case, the modulation method in the studio will be described as BST-OFDM, but the present invention is not limited to this, and OFDM modulation may be used.
Other modulation schemes may be used.

The master station receives an STL signal (frequency f10), removes noise, and outputs a broadcast IF signal and a relay IF signal (STL-RX1 in the figure).
3 and a relay IF signal from the STL receiver 3,
A TTL transmitter (TTL-TX1 in the figure) 4 for transmitting a TTL signal with a frequency f21 and a broadcast wave IF signal from the STL receiver 3 are input, and the television receiver (TV- RX) 9 and a broadcast transmitter (BC-TX1 in the figure) 5 for transmission to the RX 9.

The slave station / relay station (2) receives a TTL signal (frequency f21), removes noise, and outputs a broadcast wave IF signal and a relay wave IF signal.
TL-RX2) 6 and a relay wave IF from the TTL receiver 6.
TT to input signal and transmit as TTL signal of frequency f32
An L transmitter (TTL-TX2 in the figure) 7 and a broadcast IF signal from a TTL receiver 6 are input and transmitted to a television receiver (TV-RX in the figure) 9 at a TV broadcast frequency f1-2. And a broadcasting transmitter (in the figure, BC-TX2) 8. In addition, slave station / relay station (3), (4) (not shown)
Has the same configuration as that of the slave / relay station (2).

The slave station / relay station (5) receives a TTL signal (frequency f54), removes noise and outputs a broadcast wave IF signal (TTL-RX5), and a TTL receiver (TTL).
A broadcast transmitter (BC-TX5) for receiving a broadcast wave IF signal from a receiver and transmitting the broadcast wave IF signal to a television receiver (TV-RX) at a TV broadcast frequency f1-5.

Television receivers (TV-RX1, TV-RX2
,..., TV-RX5) 9 are TV broadcast frequencies f1-1, f1-2,. 5 Receive (same frequency) and broadcast the broadcast program.

Next, according to the embodiment of the present invention, the STL /
The schematic operation of the terrestrial digital TV broadcasting system that realizes the TTL transmission method will be described with reference to FIG. In the terrestrial digital TV broadcasting system according to the present embodiment, video, audio, data,
-Modulated into a broadcast IF signal by the OFDM modulator 1
L reference signal (FM reference signal, pilot carrier) output to the L transmitter 2 and used by the STL transmitter 2 for broadcast IF signal and frequency synchronization and phase noise removal on the receiving side
Are frequency multiplexed and transmitted to the master station at frequency f10.

At the master station, the STL signal of frequency f10
L, received by the L receiver 3, noise cancellation is performed using various reference signals, the broadcast IF signal and the relay IF signal from which noise has been removed are reproduced, and the relay IF signal is
The L transmitter 4 converts the TTL signal into a TTL signal having a frequency f21, transmits the TTL signal, and transmits the TTL signal to the slave station / relay station (2). On the other hand, STL
The broadcast wave IF signal reproduced by the receiver 3 is output to the broadcast transmitter 5, and the broadcast transmitter 5 outputs the TV broadcast frequency f1-
The data is converted to 1 and transmitted to the television receiver (TV-RX) 9, where the broadcast program is broadcast.

Next, the internal configuration of the STL transmitter 2 in the studio in the terrestrial digital TV broadcasting system of the present invention will be specifically described with reference to FIG. FIG. 2 is a block diagram showing the internal configuration of the STL transmitter 2 in the terrestrial digital TV broadcasting system of the present invention. The inside of the STL transmitter 2 in the studio in the terrestrial digital TV broadcasting system of the present invention includes a pilot carrier generation unit 21, a reception-side frequency reference signal generation unit 22, an FM reference signal generation unit 23, and an OW generation unit 24. , A frequency multiplexing unit 25, a transmission frequency converting unit 26, and a power amplifying unit 27.

The components inside the STL transmitter 2 according to the present invention will be described. The pilot / carrier generation unit 21 sets ST
The STL transmitter 2 and the TTL receiver 6
This is to generate a pilot carrier for canceling a frequency shift (phase noise) of the TL transmitter 4.
Normally, the pilot carrier is a broadcast wave IF signal (BST-O
This signal has a frequency position slightly away from FDM). As a specific pilot carrier generation method, BST
A PLL (Phase Locked Loop:
A phase locked loop) is used to obtain a pilot carrier of a predetermined frequency. Here, BST-
Although the pilot carrier is generated using the reference signal from the OFDM modulator 1 as a reference signal, the frequency of the pilot carrier is essentially changed to BST-OFDM
There is no need to synchronize with the reference signal from modulator 1.

The receiving-side frequency reference signal generating section 22 receives the ST
A high-accuracy low-frequency reference signal (reception-side frequency reference signal) used in the L receiver 3, the TTL receiver 6, and the broadcast transmitter 5 is generated. However, when the broadcast transmitter 5 has an independent reference signal, the low frequency reference signal generated here may not be transmitted to the broadcast transmitter 5 in some cases. As a specific low-frequency reference signal generation method, first, a high-precision reference signal output from the BST-OFDM modulator 1 is frequency-divided to obtain a high-precision low-frequency reference signal. Narrow band pass filter (BPF) with center frequency (BPF in the figure)
1) to remove spurious components to obtain a single-spectrum high-precision low-frequency reference signal.

The FM reference signal generation unit 23 transmits the reception frequency reference signal generated by the reception frequency reference signal generation unit 22 to the reception side (the STL receiver 3 and the TTL receiver 6). It is to generate a modulated wave (FM reference signal) of the frequency reference signal. Note that the FM reference signal generation unit 23 performs degradation of noise, interference, interference, fading, and the like on a transmission path that occurs when the reception frequency reference signal generated by the reception frequency reference signal generation unit 22 is transmitted without modulation. Is reduced by the degree of FM improvement by wideband FM modulation. As a specific FM reference signal generation method, a high-precision reference signal output from the BST-OFDM modulator 1 is used as a reference signal,
A carrier of a predetermined frequency is acquired by L, and the carrier is subjected to wideband FM modulation with the reception-side frequency reference signal output from the reception-side frequency reference signal generation unit 23. Here, the carrier is generated using the reference signal from the BST-OFDM modulator 1 as a reference signal, but there is essentially no need to synchronize the frequency of the wideband FM modulation carrier with the reference signal.

The OW generation section 24 generates a modulation signal (OW signal) of maintenance information from an OW (Order Wire: meeting line) which is an auxiliary line for maintenance or the like. As a specific OW signal generation method, a high-precision reference signal output from the BST-OFDM modulator 1 is used as a reference signal to acquire a carrier of a predetermined frequency by a PLL,
The carrier is identified by an external maintenance information signal (OW).
PSK (Quadrature Phase Shift Keying) modulation and O
A W signal e is generated.

The frequency multiplexing unit 25 adds the pilot carrier from the pilot carrier generation unit 21, the FM reference signal from the FM reference signal generation unit 23, and the OW to the broadcast wave IF signal from the BST-OFDM modulator 1. Generator 2
In this case, the transmission IF signal is generated by frequency-multiplexing the OW signal from No. 4. As a specific frequency multiplexing method, each signal is attenuated or amplified by an attenuator or an amplifier, and then frequency multiplexed by an adder.
By adjusting the attenuator attenuation or amplifier gain for each signal, a predetermined multiplex ratio can be obtained.

The transmission frequency conversion unit 26 generates a transmission local oscillation signal for obtaining the STL transmission frequency by the microwave, and uses the transmission local oscillation signal to convert the transmission IF signal output from the frequency multiplexing unit 25. The frequency is converted into a transmission frequency (high-frequency microwave).
As a specific transmission frequency conversion method, BST-OFD
Using the high-precision reference signal output from the M modulator 1 as a reference signal, a transmission local oscillation signal of a predetermined frequency is acquired by a PLL, and the frequency of the output signal from the frequency multiplexing unit 25 is transmitted by the transmission local oscillation signal. The frequency is converted to a frequency, and the band is limited by a band-pass filter (BPF2 in the figure). Here, BST-OFD
Although the transmission local oscillation signal is generated using the reference signal from the M modulator 1 as a reference signal, there is essentially no need to synchronize the frequency of the local oscillation signal with the reference signal.

The power amplifier 27 generates a transmission output of a specified power. After amplifying the power to a predetermined power by an amplifier, the power is amplified by a low-pass filter (LPF) to limit the band. High frequency unnecessary components are removed and transmitted from the antenna.

Next, the operation inside the STL transmitter 2 of the present invention will be described with reference to FIGS. FIG. 3 is a characteristic diagram showing a frequency characteristic of a signal in each part inside the STL transmitter 2 of the present invention. In the STL transmitter 2 of the present invention,
The broadcast IF signal output from the BST-OFDM modulator 1 and the high-precision reference signal are input, and the broadcast IF signal a (BST-OFDM portion in FIG. 3) shown in FIG. It is input to the multiplexing unit 25.

Then, pilot carrier b (PILOT in FIG. 3) shown in FIG. 3B is generated by pilot carrier generating section 21 using the reference signal from BST-OFDM modulator 1 as a reference signal. The receiving-side frequency reference signal generation unit 22 converts the high-precision reference signal
A low-frequency high-accuracy reception-side frequency reference signal c (reception reference signal in FIG. 3) shown in (c) is generated, and is subjected to wideband FM modulation by the FM reference signal generation unit 23, and is shown in FIG. 3 (d). An FM reference signal d (FM reference signal in FIG. 3) is generated and output. Further, an OW signal e (OW in FIG. 3) shown in FIG. 3E is generated by the OW generation unit 24 using the reference signal from the BST-OFDM modulator 1 as a reference signal, and output to the frequency multiplexing unit 25. You.

Then, the broadcast wave IF signal a from the BST-OFDM modulator 1 and the pilot / carrier generator 21
, The FM reference signal d from the FM reference signal generator 23, and the OW signal e from the OW generator 24 are frequency-multiplexed by the frequency multiplexer 25,
The transmission IF signal f shown in FIG. 3F is converted into a high-frequency transmission frequency in the microwave band by the transmission frequency converter 26, amplified by the power amplifier 27, and transmitted from the antenna. I have. In FIG. 3, (f) and (g) are shown at the same position with respect to the horizontal axis frequency, but show that each signal component has frequency characteristics at the same interval. The order of the frequencies in both figures is different. That is, (f) is the IF band, and (g) is the high frequency band (microwave band).

Next, the internal configuration of the STL receiver 3 in the master station or the TTL receiver 6 in the slave station / relay station in the terrestrial digital TV broadcasting system of the present invention will be specifically described with reference to FIG. FIG. 4 shows a terrestrial digital T of the present invention.
FIG. 2 is a block diagram showing the internal configuration of an STL receiver 3 or a TTL receiver 6 in a V broadcast system. In the terrestrial digital TV broadcasting system according to the present invention, the STL receiver 3 in the master station or the TTL receiver 6 in the slave / relay station includes a reception F / E unit 30, a reception IF unit 31, a frequency multiplex division unit. 32, local noise canceller 33, and OW
And a playback unit 39.

The components inside the STL receiver 3 or TTL receiver 6 of the present invention will be described. The reception F / E unit 30
Receiver front end, high frequency (microwave band)
Of the input signal h, which is the STL / TTL signal of FIG. As a specific frequency conversion method, an input signal h from the antenna is low-noise amplified by an amplifier, and a high-frequency band-pass filter (BPF-R in the figure) is used.
After the spurious signal is removed in F), the reception-side frequency reference signal transmitted by the FM reference signal is used as a reference signal, and the frequency is converted to a reception IF signal by a local oscillation signal of a predetermined frequency obtained by the PLL. still,
Here, the local oscillation signal is generated using the reception-side frequency reference signal as a reference signal, but there is essentially no need to synchronize the frequency of the local oscillation signal with the reception-side frequency reference signal.

The reception IF unit 31 receives the I / O
The target wave is selected from the signals converted into the F signal and output as the reception IF signal i. In particular,
The IF signal frequency-converted by the reception IF unit 31 is band-limited by an intermediate frequency band-pass filter (BPF-IF in the figure), and the AGC (Automa
Tic Gain Control) Amplifies and stabilizes the level to output a received IF signal.

The frequency division multiplexing section 32 multiplexes a signal frequency-multiplexed on the transmitter side for processing on the receiver side. As a specific multiplex division method, a band-pass filter (Band Pass Filter: BP) that distributes the reception IF signal i and restricts each band after distribution to each band.
F) to extract only necessary signal components in each branch, reduce unnecessary signal components, and perform multiplex division. As shown in FIG. 4, the BPF1 extracts the pilot carrier signal component j, the BPF2 extracts the FM reference signal 1, the BPF3 extracts and outputs the OW signal m, and the band of the reception IF signal i. Is not limited and the signal k is output as it is.

The OW reproduction section 39 reproduces the maintenance information data (OW) from the received OW signal. Specifically, the OW reproduction section 39 converts the OW signal m divided by the frequency division division section 32 into a Q signal.
PSK (Quadrature Phase Shift Keying) demodulation is performed to obtain maintenance information data (OW).

The local noise canceller 33 removes noise from the received IF signal and outputs a broadcast IF signal and a relay IF signal having high frequency accuracy and high stability.

Here, the principle of frequency synchronization and phase noise removal (noise cancellation) in the local noise canceller 33 of the STL receiver 3 or TTL receiver 6, which is a characteristic part of the present invention, will be described in detail.

The noise removal performed by the local noise canceller 33 of the STL receiver 3 or the TTL receiver 6 is as follows.
The present invention mainly reduces phase noise superimposed on a transmitter, phase noise superimposed on a receiver, and phase noise superimposed on a transmission path. The outline of the principle of phase noise reduction is that a signal with phase noise superimposed is divided into two branches, and one branch signal is frequency-converted by a local oscillation signal with little phase noise, so that the phase noise of the other branch signal is reduced. The phase noise of the phase opposite to the rotation direction is acquired, and the signals of the two branches are frequency-converted to cancel the phase noise.

Next, the principle of frequency synchronization and phase noise reduction in the local noise canceller will be described in detail with reference to FIGS. Figure 5 shows the local
FIG. 6 is a basic configuration diagram for explaining the operation principle of noise cancellation, and FIG. 6 is a characteristic diagram showing frequency characteristics of each part of the configuration of FIG. In FIG. 6, the frequency order on the horizontal axis is different in each figure. As a basic configuration for performing noise cancellation, a divider (H in FIG. 5) 50 that divides an input signal into two branches, and a pilot carrier is extracted by limiting the band of a pilot branch which is one branch. Bandpass filter (B in the figure)
PF1) 51, a limiter amplifier (LIM in the figure) 52 for limiting and amplifying the extracted pilot carrier, a local oscillator (LO-OSC in the figure) 60 for generating a local oscillation signal with little phase noise, and the other branch , A frequency converter 61 for frequency-converting the signal of the signal branch with the local oscillation signal, a band-pass filter (BPF2 in the figure) 62 for band-limiting the frequency-converted signal, and a delay corrector ( In the figure, a delay 1) 63, a frequency converter 70 for frequency-converting the signal from the pilot branch and the signal from the signal branch, and a band-pass filter (B in the figure) for selecting only the difference component and the signal component
PF3) 71.

The operation in the configuration shown in FIG.
This will be described with reference to FIGS. The input signal is as shown in FIG.
As shown in the figure, the broadcast IF signal (BST-OFDM) modulated by the studio BST-OFDM modulator 1 and the pilot signal
The carrier (PILOT) is multiplexed, and the input phase noise (thick oblique line) is superimposed. Here, the frequency of the input pilot carrier (PILOT) is represented by f
_PLT , the frequency of the input signal (BST-OFDM) is f _sig ,
Assuming that the input phase noise is θ (t), the input phase noise θ (t) is superimposed on the input pilot carrier frequency f _PLT and the input signal frequency f _sig . f _PLT ∠θ (t) f _sig ∠θ (t)

The input signal A is distributed by a distributor 50, one of which is a pilot branch and the other is a signal branch.
Output as a branch, and in the pilot branch,
The band is limited by a band-pass filter (BPF 1 in the figure) 51, only a pilot carrier (PILOT) component is passed through and extracted, and further limited by a limiter amplifier 52. At this time, the frequency characteristics of the output signal B from the band-pass filter 51 and the output signal C from the limiter amplifier 52 are as follows:
As shown in FIG. 6 (BC), the broadcast IF signal (BST-OF
DM) components are removed and pilot carrier (PILOT)
Only the component and the input phase noise θ (t) superimposed thereon. At this time, band-pass filter (BPF1) in 51 delay occurs, when the delay time tau _BPF1, the input pilot carrier frequency f _PLT, input phase noise delayed by _{τ BPF1 θ (t-τ BPF1} ) Are superimposed, and are shown as follows. f _PLT ∠θ (t−τ _BPF1 )

On the other hand, in the signal branch, the local oscillation signal D is output from the local oscillator 60. Here, the frequency characteristic of the local oscillation signal D output from the local oscillator 60 is, as shown in FIG.
And the intra-system local phase noise superimposed thereon.
Here, assuming that the local oscillation signal frequency in the system is f _LO and the local oscillation signal phase noise in the system is φ (t), the local oscillation signal frequency f _LO in the system includes the local oscillation signal phase in the system. Since the noise φ (t) is superimposed, it is shown as follows. f _LO ∠φ (t)

In the signal branch, the frequency converter 61 frequency-converts the signal output from the distributor 50 by the local oscillation signal F from the local oscillator 60, and outputs a signal E. Here, the frequency characteristic of the signal E output from the frequency converter 61 includes a sum component and a difference component of the input signal A and the local oscillation signal D as shown in FIG. Therefore, the relationship between each signal component included in the signal E and the superposed phase noise is as follows. f _PLT −f _LO ∠θ (t) −φ (t) f _sig −f _LO ∠θ (t) −φ (t) f _PLT + f _LO ∠θ (t) + φ (t) f _sig + f _LO ∠θ ( t) + φ (t)

The frequency-converted signal E is band-limited by a band-pass filter (BPF2) 62 so that only the difference component passes, and a signal F is output. The frequency characteristic of the signal F is shown in FIG. As shown in (), the sum component in (E) is removed and only the difference component exists. At this time,
A delay occurs in the band-pass filter (BPF2) 62,
If this delay time is τ _BPF2 , the phase noise superimposed on the extracted difference component is delayed by τ _BPF2 , and the relationship between each signal component included in the signal F and the superimposed phase noise is as follows: It looks like this: f _PLT −f _LO ∠θ (t−τ _BPF2 ) −φ (t−τ _BPF2 ) f _sig −f _LO ∠θ (t−τ _BPF2 ) −φ (t−τ _BPF2 )

The signal F is supplied to a delay compensator (delay 1).
At 63, the bandpass filter (B
PF1), a delay is applied so as to be equivalent to the delay time in 51, and a signal G is output. Here, _assuming that the delay time of the band-pass filter (BPF2) 62 is τ _BPF2 and the delay time of the delay corrector 63 is Δt with respect to the delay time τ _BPF1 of the band-pass filter (BPF1) 51, τ _BPF1 = τ _The delay Δt is added by the delay corrector 63 so that _BPF2 + Δt is obtained, and the delay time difference from the pilot branch is equalized. As a result, the frequency characteristic of the signal G does not change, and becomes as shown in FIG. 6G. The relationship between each signal component included in the signal G and the phase noise to be superimposed is that the phase noise has a delay Δt. The following is added. f _PLT −f _LO ∠θ (t−τ _BPF2 −Δt) −φ (t−τ
_BPF2 −Δt) f _sig −f _LO ∠θ (t−τ _BPF2 −Δt) −φ (t−τ
_BPF2 -Δt)

Then, the signal G of the signal branch,
The signal C of the pilot branch output from the limiter amplifier 52 described above is frequency-converted by the frequency converter 70 to output a signal H. Here, the frequency converter 7
As shown in FIG. 6H, the frequency characteristic of the signal H output from 0 includes a sum component and a difference component of the signal G and the signal C. Therefore, the relationship between each signal component included in the signal H and the superposed phase noise is as follows. _{f PLT - (f PLT -f LO} ) ∠θ (t-τ BPF1) - {θ (t-τ BPF2
_{-Δt) -φ (t-τ BPF} 2 -Δt)} f PLT - (f sig -f LO) ∠θ (t-τ BPF1) - {θ (t-τ BPF2
−Δt) −φ (t−τ _{BPF 2} −Δt)｝ f _PLT + (f _PLT −f _LO ) ∠θ (t−τ _BPF1 ) + ｛θ (t−τ _{BPF2
-Δt) -φ (t-τ BPF} 2 -Δt)} f PLT + (f sig -f LO) ∠θ (t-τ BPF1) + {θ (t-τ BPF2
-Δt) -φ (t-τ _{BPF 2} -Δt)｝

Here, the delay Δt in the delay corrector 63
Is equivalent to the delay time difference between the signal branch and the pilot branch by adding a delay Δt so that τ _BPF1 = τ _BPF2 + Δt as described above. Become. _{f LO ∠φ (t-τ BPF2} -Δt) f LO - (f sig -f PLT) ∠φ (t-τ BPF2 -Δt) 2 × f PLT -f LO ∠2 × θ (t-τ BPF1) - φ
_{(T-τ BPF2 -Δt) f} PLT + (f sig -f LO) ∠2 × θ (t-τ BPF1) -φ
(T−τ _BPF2 −Δt)

Here, focusing on the difference component, the frequency of the output signal component is the frequency (f _LO ) of the local oscillation signal in the system regardless of the frequency of the input signal, that is, is constant. In addition, the sideband of the signal when focusing on the pilot carrier is inverted between input and output. The phase noise of the output signal is such that the input phase noise θ (x) is cancelled, and instead the phase noise φ of the local oscillation signal in the system is
(X). That is, if the phase noise φ (x) of the local oscillation signal in the system is sufficiently small, the phase noise of the input signal is sufficiently reduced and output.

Therefore, the signal H whose frequency has been converted by the frequency converter 70 is output by a band-pass filter (BPF3) 71.
The signal I is output after being band-limited so that only the difference component and only the signal (BST-OFDM) component pass. The frequency characteristic of the signal I is as shown in FIG. The pilot carrier (PILOT) component in the sum component and the difference component is removed, and only the signal component of the difference component (BST-OFDM) is present. , As follows: f _LO − (f _sig −f _PLT ) ∠φ (t−τ _BPF2 −Δt)

According to the principle of frequency synchronization and noise elimination of the local noise canceller described above, for example, even if a frequency deviation occurs in the input signal, the local oscillator 6
Since an output signal having a high frequency accuracy according to the local oscillation frequency and having high stability can be obtained, the frequency deviation of the input signal can be eliminated, and the phase noise of the output signal is superimposed on the input signal. Phase noise θ (x) is cancelled, and only the phase noise φ (x) of the local oscillation signal in the system is substituted. Therefore, if the phase noise φ (x) of the local oscillation signal in the system is sufficiently small, It is understood that the phase noise of the input signal is sufficiently reduced and output.

Next, the internal configuration of the local noise canceller 33 in the STL receiver 3 or the TTL receiver 6 of the digital TV broadcasting system of the present invention for realizing the above-described principle of the local noise canceller will be described. This will be described with reference to FIG. The local noise canceller 33 of the digital TV broadcasting system according to the present invention includes a pilot carrier reproducing unit 34, a receiving-side frequency reference signal reproducing unit 35, and a high stability local oscillation signal reproducing unit 3.
6, a broadcast wave IF signal reproducing unit 37, and a relay wave IF signal reproducing unit 38.

The components inside the local noise canceller 33 will be described. Pilot / Carrier Regeneration Unit 3
4 is to eliminate the frequency shift at the transmitter and the frequency shift at the receiver, and to cancel the phase noise superimposed at the transmitter, the phase noise superimposed at the receiver, and the phase noise superimposed at the transmission line. To regenerate the pilot carrier. As a specific pilot carrier reproducing method, a delay corrector 1 (delay 1 in FIG. 1) applies delay correction to a pilot carrier signal component j extracted by the frequency division multiplexing section 32, and a limiter amplifier (L in FIG. 1
IM) to obtain a predetermined level,
The pilot carrier reproduction signal (f _PILOT ) is obtained by stabilizing the level.

The delay in the delay compensator 1 is used together with the delay compensator 2 of the broadcast wave IF signal reproducing unit 37 and the delay compensator 3 of the relay IF signal reproducing unit 38 to be described later. IF signal and pilot
This is for correcting the relative delay between the carrier and the relay wave IF signal, and is a process for absorbing a delay time difference between BPFs (specifically, BPF1, BPF4, and BPF6) inserted into the processing system of each branch. . A pilot carrier reproduced signal (f _PILOT ) reproduced with delay correction
Are distributed by a distributor (H in FIG. 1) and supplied to a broadcast wave IF signal reproducing unit 37 and a relay wave IF signal reproducing unit 38.
It is used to cancel the phase noise superimposed on the received wave.

The receiving side frequency reference signal reproducing unit 35
It reproduces a receiving-side frequency reference signal used by the L receiver 3, TTL receiver 6, TTL transmitter 4, and broadcast transmitter 5. However, when the broadcast transmitter 5 has an independent reference signal, the receiving-side frequency reference signal generated here may not be transmitted to the broadcast transmitter 5 in some cases. As a specific method of reproducing the receiving-side frequency reference signal, the FM reference signal component 1 extracted by the frequency division multiplexing unit 32 is detected by a frequency modulation demodulator (FM DEM in FIG. 1), and the frequency is set to the center frequency. Through a narrow band pass filter (BPF8 in the figure) to remove spurious components,
A single-spectrum receiving-side frequency reference signal is obtained. The reproduced frequency reference signal on the receiving side is received by the receiving F / E in the STL receiver 3 or the TTL receiver 6.
The signal is supplied to the unit 30 and the high stability local oscillation signal reproducing unit 36, and is transmitted to the TTL transmitter 4 and the broadcast transmitter 5.

The high-stability local oscillation signal reproducing section 36 eliminates the frequency deviation of the received IF signal and removes noise to remove the broadcast frequency IF signal and the relay wave I signal having high frequency accuracy and high stability.
A local oscillation signal (f _{LO-STD in} FIG. 1) used to reproduce the F signal is generated. As a specific local oscillation signal generation method, a carrier having a predetermined frequency is acquired by a PLL using the reception-side frequency reference signal reproduced by the reception-side frequency reference signal reproduction unit 35 as a reference signal. In order to eliminate the frequency deviation and improve the accuracy of removing the phase noise in the local noise canceller 33, the local oscillation signal generated here has high purity, that is, high CNR (Carrier to Noise Rati).
Although it is necessary to be o), high accuracy and high stability of the local oscillation signal can be achieved by synchronizing with the reception frequency reference signal transmitted from the transmission side by the FM reference signal.

The broadcast wave IF signal reproducing section 37 removes the pilot carrier, the FM reference signal, and the OW signal added to the OFDM wave for the STL transmission by the STL transmitter 2, extracts only the OFDM wave, and transmits the signal. In addition to reducing the frequency shift and phase noise added to the STL / TTL wave in the transmitter, the transmission path, and the receiver, it reproduces a broadcast IF signal of a specified frequency. As a specific method of reproducing the broadcast wave IF signal, in accordance with the principle of local noise cancellation, first, as preprocessing for phase noise cancellation, the reception IF signal k output from the frequency division multiplexing unit 32 is converted to a high stability signal. The frequency is converted by the local oscillation signal having high frequency accuracy and high stability generated by the local oscillation signal reproducing unit 36, and only a necessary component is extracted by a band-pass filter (BPF4 in FIG. 1). Then, in order to cancel the phase noise, the delay is corrected by the delay corrector 2 (delay 2 in FIG. 1), and the delay time and the delay time of the pilot carrier branch are equalized.
Here, the delay time of the pilot carrier branch is
This is roughly the delay time of BPF1. Then, by performing frequency conversion with the pilot carrier output from the pilot carrier reproducing unit 34, high-precision frequency reproduction and phase noise cancellation are performed, and a bandpass filter (BPF5 in FIG. 1) removes spurious components. , Only the target wave is extracted and output as a broadcast wave IF signal q.

The relay IF signal reproducing section 38 reduces the frequency shift and phase noise added to the STL / TTL wave in the transmitter, the transmission path, and the receiver, and reproduces a relay IF signal having a specified frequency. It is. As a specific method of reproducing the relay wave IF signal, in accordance with the principle of local noise cancellation, in the broadcast wave IF signal reproducing unit 37, the frequency is converted and distributed by the local oscillation signal from the high stability local oscillation signal reproducing unit 36. The band-pass filter (BPF 6 in FIG. 1) extracts only necessary components from the signal thus obtained, and performs delay correction by a delay corrector 3 (delay 3 in FIG. 1) to cancel phase noise. Equalize the delay time of the carrier branch with the delay time. Here, the delay time of the pilot carrier branch is approximately BPF1
Is the delay time. Then, by performing frequency conversion with the pilot carrier output from the pilot carrier reproducing unit 34, high-precision frequency reproduction and phase noise cancellation are performed, and a band-pass filter (BPF in FIG. 1) is used.
In 7), the spurious component is removed, and only the target wave is extracted and output as the relay IF signal r. The necessary components extracted by the band-pass filter (BPF 6 in the figure) can be relayed without having a frequency multiplexing unit or the like in the TTL transmitter 4 in order to simplify the configuration in the TTL transmitter 4. In this way, the band is limited in a band including all components of the OW signal, the FM reference signal, the BST-OFDM, and the pilot carrier.

The operation of the local noise canceller 33 of the present invention for realizing the above-described principle of local noise cancellation will be described. As shown in FIG. 4, a frequency deviation occurs, and phase noise is further superimposed. The received IF signal i is divided by the frequency division division unit 32 and
BPF1 in the frequency division multiplexing unit 32 corresponding to the branch
The pilot carrier signal component j band-limited by is delayed by the pilot carrier reproducing unit 34 to generate a pilot carrier reproduced signal f _PILOT . On the other hand, the signal k, which is a branch corresponding to the signal branch, which is not subjected to band limitation, is frequency-converted by the local oscillation signal having high frequency accuracy and high stability generated by the high-stability local oscillation signal reproducing unit 36, and further subjected to the BPF 4 and the delay. In step 2, the phase noise of the pilot carrier reproduction signal f _{PILOT having} the phase opposite to the phase rotation direction of the pilot carrier reproduced signal f
By performing frequency conversion between the carrier reproduction signal and the signal n for the broadcast wave IF signal, a frequency deviation superimposed on the received wave is eliminated, and a broadcast wave IF signal in which phase noise (input phase noise) is canceled can be obtained. Things.

Similarly, in the broadcast wave IF signal reproducing section 37, the BPF 6 and the delay signal are converted from the signal frequency-converted by the high-frequency local oscillation signal having high frequency accuracy and high stability generated by the high stability local oscillation signal In step 3, the phase noise of the pilot carrier reproduction signal f _PILOT is obtained in the reverse direction from the phase rotation direction of the phase noise of the pilot carrier reproduced signal f _PILOT in the relay wave IF signal.
By performing frequency conversion between the carrier reproduction signal and the signal o for the relay IF signal, a frequency deviation superimposed on the received wave is eliminated, and a relay IF signal in which phase noise (input phase noise) is canceled can be obtained. Things.

Next, the STL receiver 3 in the master station of the present invention,
Alternatively, an operation inside the TTL receiver 6 in the slave station / relay station will be described with reference to FIGS. FIG. 7 shows the S value of the present invention.
FIG. 9 is a characteristic diagram illustrating frequency characteristics of signals in various parts inside the TL receiver 3 or the TTL receiver 6. In FIG. 7, the frequency order on the horizontal axis is different in each figure. In the STL receiver 3 in the master station or the TTL receiver 6 in the slave station / relay station of the present invention, the STL transmitter 2 in the studio, the TTL transmitter 4 in the master station, or the TTL in the slave station / relay station in the preceding stage. A received signal h, which is an STL signal or a TTL signal transmitted from the transmitter 7, is input.
As shown in (h), a broadcast IF signal (BST-OFDM),
A pilot carrier (PILOT), an FM reference signal,
An OW signal (OW) component is included.

Then, the high-frequency (microwave band) STL
The signal or TTL signal h is frequency-converted into an IF signal by the reception F / E unit 30, a target wave is selected by the reception IF unit 31, and output as a reception IF signal i having characteristics shown in FIG. In FIG. 7, (h) and (i) are shown at substantially the same position with respect to the horizontal axis frequency, but show that each signal component has frequency characteristics at the same interval. The order of the frequencies in the two figures is different. That is, (h) is a high frequency band (microwave band),
(I) is the IF band. Although the signal h and the signal i have inverted sidebands, the sidebands of the received IF signal k and the relay IF signal r are inverted in the subsequent local noise canceller 33. Therefore, the reception IF unit 31 passes the component whose sideband is inverted so that the TTL transmission signal between each slave station / relay station becomes the same.

Then, the received IF signal i is divided into four branches by the frequency division multiplexing section 32. The first is a signal j of the characteristic of FIG. 7 (j) from which the pilot carrier signal component is extracted, and the second is a signal k of the characteristic of FIG. 7 (k) which directly outputs the received IF signal. Third,
The signal l having the characteristics shown in FIG.
The fourth is FIG. 7 (m) in which the OW signal component is extracted.
Is a signal m having the following characteristics.

Then, the pilot carrier signal component j
Is delayed and corrected by a pilot carrier reproducing unit 34 in the local noise canceller 33, is subjected to limiter amplification, and is output as a pilot carrier reproduced signal f _PILOT. Supplied to The FM reference signal component 1 is demodulated (detected) by the receiving-side frequency reference signal reproducing unit 35 to reproduce the low-frequency receiving-side frequency reference signal n shown in FIG. And supplied to the high-stability local oscillation signal reproducing unit 36 in the local noise canceller 33, and output from the STL receiver 3 or the TTL receiver 6 to the broadcast transmitter 5 and the TTL transmitter 4. It has become so. Then, the high-stability local oscillation signal reproducing unit 36 uses the receiving-side frequency reference signal n supplied from the receiving-side frequency reference signal reproducing unit 35 to generate a high-frequency accuracy and high-stability local oscillation signal (f _{LO− STD} ) is generated and supplied to the broadcast wave IF signal reproducing unit 37.

The received IF signal was output as it was.
The signal k is broadcast in the local noise canceller 33
Wave IF signal reproducing unit 37, a high stability local oscillation signal reproducing unit
The local oscillation signal (f_LO-STD) With frequency conversion
And only the necessary components are extracted by the bandpass filter (BPF4).
FIG. 7 shows the state after the delay is corrected by the delay corrector 2.
The signal of only the broadcast IF signal (BST-OFDM) component shown in (o)
Signal o, which is the pilot carrier
Since the delay time and the delay time are equalized, (f
_PILOT−f_LO-STD)It turns out that.

The signal o is subjected to frequency conversion by a pilot carrier reproduced signal (f _PILOT ) output from the pilot carrier reproducing section 34, so that high-precision frequency reproduction and phase noise cancellation are performed. Done,
Further, the spurious component is removed by the band-pass filter (BPF5), and only the target wave is extracted. The broadcast wave IF signal p having the characteristic shown in FIG. Here, the broadcast wave IF signal p is a signal o (f
_PILOT − f _LO-STD ) and pilot carrier (f _PILOT )
F _PILOT − (f _PILOT
−f _LO-STD ) = f _LO-STD , the frequency deviation of the received wave is eliminated, and the phase noise (input phase noise) superimposed on the received wave is cancelled. A broadcast IF signal is obtained and output to the broadcast transmitter 5.

Similarly, the broadcast wave IF signal reproducing section 37 distributes a signal obtained by frequency-converting the signal k from the local oscillation signal (f _LO-STD ) from the high stability local oscillation signal reproducing section 36 from the signal k. The bandpass filter (B
Only the necessary components are extracted by the PF 6), the delay is corrected by the delay corrector 3, and the relay IF signal (OW signal, FM reference signal, BST-OFDM, pilot carrier) components shown in FIG. Is output, and this is equalized to the delay time of the pilot carrier branch, so that it becomes (f _PILOT −f _LO-STD ). Then, the signal q is subjected to frequency conversion with a pilot carrier reproduced signal (f _PILOT ) output from the pilot carrier reproducing section 34, _thereby reproducing a high-precision frequency and canceling phase noise. Further, the spurious component is removed by the band-pass filter (BPF 7), and only the target wave is extracted, and the relay IF signal r having the characteristic shown in FIG. 7 (r) is output to the TTL transmitter 4.
Here, the relay wave IF signal r is a signal q (f _PILOT −f
_LO-STD ) and the result of frequency conversion between the pilot carrier (f _PILOT ) and f _PILOT − (f _PILOT −f
_LO-STD ) = f _LO-STD , the frequency deviation of the received wave is eliminated, the phase noise (input phase noise) superimposed on the received wave is canceled, and the relay IF having a high precision frequency and high stability is obtained. A signal is obtained and the TTL transmitter 4 or TTL
Output to the receiver 6.

On the other hand, the OW signal m divided by the frequency division multiplexing section 32 is demodulated by the OW reproduction section 39, and OW is output.

Next, the internal configuration of the TTL transmitter 4 in the master station or the TTL transmitter 7 in the slave station / relay station in the terrestrial digital TV broadcasting system of the present invention will be specifically described with reference to FIG. FIG. 8 shows a terrestrial digital T according to the present invention.
FIG. 2 is a block diagram showing the internal configuration of a TTL transmitter 4 or a TTL transmitter 7 in a V broadcast system. The TTL transmitter 4 in the master station or the TTL transmitter 7 in the slave / relay station in the terrestrial digital TV broadcasting system of the present invention includes a transmission frequency converter 40 and a power amplifier 41.

The components inside the TTL transmitter 4 or TTL transmitter 7 of the present invention will be described. Transmission frequency converter 40
Generates a transmission local oscillation signal for obtaining a TTL transmission frequency by a microwave, and converts the frequency of a relay IF signal into a transmission frequency (high-frequency microwave) using the transmission local oscillation signal. is there. As a specific frequency conversion method, a high-precision receiving-side frequency reference signal output from the STL receiver 3 or the TTL receiver 6 is used as a reference signal to acquire a transmission local oscillation signal of a predetermined frequency obtained by a PLL. The relay local IF signal output from the STL receiver 3 or the TTL receiver 6 is subjected to frequency conversion with the transmission local oscillation signal, and spurious is removed by a bandpass filter (FIL in the figure).
In this case, the transmission local oscillation signal is obtained using the reception-side frequency reference signal output from the STL receiver 3 or the TTL receiver 6 as a reference signal. However, the frequency of the local oscillation signal is essentially changed to the reception side. There is no need to synchronize to the frequency reference signal.

The power amplifying section 41 generates a transmission output of a specified power. Specifically, the power is amplified to a predetermined power by an amplifier (PA in the figure), and then a low-pass filter (Low Pa filter).
An ss Filter (LPF) limits the band to remove unnecessary high frequency components, and transmits the signals from the antenna.

Next, the TTL transmitter 4 of the present invention or the TTL
The operation of the transmitter 7 will be described with reference to FIG. FIG.
FIG. 3 is a characteristic diagram showing frequency characteristics of signals in respective parts inside the TTL transmitter 4 or the TTL transmitter 7 of the present invention.
In FIG. 9, the frequency order on the horizontal axis is different in each figure, (h) and (s) are high-frequency microwave bands, and (r) is the IF band. In the present invention, the STL transmitter 2 of the studio, or the TTL transmitter 4 of the master station,
Alternatively, the STL / TTL signal h shown in FIG. 9 (h) transmitted from the transmitter 7 of the preceding slave station / relay station TTL is subjected to frequency synchronization and phase noise removal in the STL receiver 3 or the TTL receiver 6. , The relay IF signal r shown in FIG.
And the reception frequency reference signal n are output.
In the transmitter 4 or the TTL transmitter 7, in the transmission frequency converter 40, the relay IF signal is frequency-converted by the transmission local oscillation signal transmitted according to the reception-side frequency reference signal n, and the high-frequency signal shown in FIG. The TTL signal is output, the power is amplified by the power amplifying unit 41, and the TTL signal of the relay wave is transmitted from the antenna.

Next, the operation of the terrestrial digital TV broadcast system for realizing the terrestrial digital TV broadcast transmission method of the present invention will be described with reference to FIG. 1 while focusing on the features of the present invention. The operation of the terrestrial digital TV broadcasting system according to the present invention is as follows. In the system configuration shown in FIG.
The T-OFDM modulator 1 modulates the broadcast IF signal (BST-OFDM) into a broadcast IF signal (BST-OFDM) and outputs the modulated IF signal together with a high-precision reference signal to the STL transmitter 2. And a pilot carrier used for noise removal and a receiving-side frequency reference signal are generated. The receiving-side frequency reference signal is subjected to high-frequency FM modulation to generate an FM reference signal, and a broadcast IF signal, a pilot carrier, and F
The M reference signal is frequency-multiplexed to generate a transmission IF signal, which is transmitted as a high frequency (microwave) f10 STL signal.

The STL signal is received by the STL receiver 3 of the master station, frequency-converted into a reception IF signal, a pilot carrier and an FM reference signal are extracted from the reception IF signal, and the local noise canceller is extracted. At FM
Demodulate the reference signal to reproduce the receiving-side frequency reference signal, and use the reproduced receiving-side frequency reference signal to obtain high-frequency characteristics,
A local oscillation signal having high stability is generated, and the received IF signal is frequency-converted by the local oscillation signal. Then, the broadcast wave IF signal is extracted from the frequency-converted signal and frequency-converted using a pilot carrier, thereby reducing the frequency deviation and phase noise and canceling the noise. And the receiving-side frequency reference signal are output to the broadcasting transmitter 5, and are converted into the TV broadcasting frequency f1-1 based on the receiving-side frequency reference signal by the broadcasting transmitter 5, so that the television receiver (TV- R
X) 9 and the broadcast program is broadcast on the television receiver 9.

In the STL receiver 3, the broadcast wave I
The relay IF signal including the F signal, the pilot carrier, and the FM reference signal is also extracted by the local noise canceller from the signal that has been frequency-converted by the high-precision local oscillation signal, and the pilot IF signal is extracted. -Frequency conversion using a carrier reduces frequency deviation and phase noise to cancel noise, and outputs the noise-cancelled relay IF signal and the receiving-side frequency reference signal to the TTL transmitter 4; TTL transmitter 4
Is converted into a TTL signal of a high frequency (microwave) f21 based on the receiving-side frequency reference signal and transmitted, and transmitted to the slave / relay station (2).

Thereafter, in each slave station / relay station, the broadcast wave IF signal is transmitted from the broadcast transmitter 8 by the TTL receiver 6 in the same operation as the master station STL receiver 3 while performing frequency synchronization and noise cancellation. The relay IF signal transmitted to the television receiver 9 is relayed from the TTL transmitter 7 to the next slave station / relay station.

Here, in the digital TV broadcasting system of the present invention, STL / TTL transmitted between the respective devices is used.
The frequency characteristics of the signal will be described with reference to FIG.
FIG. 10 is an explanatory diagram showing an example of a frequency characteristic (spectrum) of an STL / TTL signal and an example of an emission mask according to the present invention. In the digital TV broadcasting system of the present invention, as shown in FIG. 10, one channel of the STL / TTL signal transmitted between the devices is BST-OFDM modulated by the studio BST-OFDM modulator 1. It comprises a broadcast IF signal (BST-OFDM), a pilot carrier multiplexed by the STL transmitter 2, an FM reference signal, and an OW signal. In the example of FIG. 10, the broadcast wave IF signal modulated by BST-OFDM has 1
One BST segment is about 429 kHz, and 13 BST segments
It consists of ST segments, and the broadcast wave IF signal is about 5.6 MHz. Then, the pilot carrier is placed about 4 B below the broadcast wave IF signal (BST-OFDM).
29 kHz apart and the FM reference signal is broadcast wave I
The frequency band is about 429 kHz from the frequency about 429 kHz above the F signal (BST-OFDM), and the OW signal is the frequency band about 429 kHz from the frequency about 429 kHz above the FM reference signal.

As a result, OW from pilot carrier
The bandwidth up to the signal is about 7.7 MHz, and when the Guard Band with the adjacent channel is secured by 650 kHz,
The channel width becomes 90 MHz. Therefore, it is sufficient if the required bandwidth is 8 MHz or less and a side-lop characteristic from the required bandwidth to the channel width of 9 MHz can be realized as the characteristic of the band-pass filter (BPF) that passes the required band.

[0083] Terrestrial digital T according to the embodiment of the present invention
According to the V broadcasting system, the STL transmitter 2 in the studio
Then, a receiving-side frequency reference signal is generated based on the reference signal from the BST-OFDM modulator 1, multiplexed with the broadcast IF signal, transmitted in the STL signal, and transmitted by the STL receiver 3 and the TTL receiver 6. A local oscillation frequency signal having high precision and high stability based on the reception-side frequency reference signal, and the local noise canceller 33 operates to locally oscillate the frequency of the reproduced broadcast wave IF signal and relay wave IF signal. Since the frequency is synchronized with the frequency of the frequency signal, the STL transmitter 2 in the studio, the TTL transmitter 4 in the master station, and the TTL transmitter 7 in each slave / relay station have a frequency deviation (deviation).
Occurs, the STL receiver 3 of the master station or each slave station /
At the stage of the TTL receiver 6 of the relay station, the broadcast wave and the relay wave to the next stage can be transmitted while always eliminating the frequency deviation, and there is an effect that high frequency accuracy can be secured as the whole digital TV broadcasting system.

In particular, according to the present invention, in the STL transmitter 2, since the receiving-side frequency reference signal is subjected to wide-band FM modulation and transmitted as the FM reference signal to the master station and the slave / relay station, noise from the transmission path, interference It is possible to transmit high-precision information without being affected by interference, fading, etc., and to reproduce a clean high-stability local oscillation signal on the receiving side.

According to the terrestrial digital TV broadcasting system according to the embodiment of the present invention, STL receiver 3 and T
The TL receiver 6 generates a high-precision and high-stability local oscillation frequency signal based on the reception-side frequency reference signal, and receives the broadcast wave IF signal and the relay wave IF signal by the operation of the local noise canceller 33. Cancels the phase noise superimposed on the local oscillation frequency signal and reduces it to only the noise superimposed on the local oscillation frequency signal.
, The local oscillation signal phase noise in the transmission frequency converter 40 of the TTL transmitters 4 and 7 of the master station and each slave / relay station, the STL receiver 3 of the master station or each slave station. / Reception F / E section 30 of TTL receiver 6 of relay station
Phase noise and phase noise added due to fading in the transmission path, etc., can always be eliminated in the receiver and the broadcast wave and the relay wave to the next stage can be transmitted. This has the effect of ensuring stability.

The STL receiver 3 of the master station or each slave station /
If the local oscillation frequency oscillator provided in the high-stability local oscillation signal reproducing unit 36 in the TTL receiver 6 of the relay station is a high-precision and high-stability oscillator, the digital TV broadcasting system as a whole has high frequency accuracy, Since high stability can be maintained, S
In the TL / TTL section, there is essentially no need to require high accuracy and high stability. In other words, the STL transmitter 2 in the studio
The local oscillator included in the transmission frequency conversion unit 26 in the TTL transmitters 4 and 7 of the master station and each slave / relay station, or the local oscillator provided in the transmission frequency conversion unit 26 or the ST of the master station.
The local oscillator provided in the receiving F / E section 30 of the L receiver 3 or the TTL receiver 6 of each slave / relay station does not need to have high accuracy and high stability (high CNR), and can be configured with an inexpensive system configuration. There are effects that can be realized.

According to the terrestrial digital TV broadcasting system of the present invention, the STL transmitter 2 in the studio
The FM reference signal and the pilot carrier are frequency-multiplexed and transmitted to the broadcast IF signal, and the STL receiver 3 of the master station and the TTL receiver 6 of the slave / relay station use the above two signals to generate local noise. The transmission frequency deviation (deviation) is canceled by the canceller 33, and the transmission signal phase noise added by fading in the transmission path, the transmission signal phase noise due to the local oscillation signal phase noise in the transmitter, and the local oscillation signal phase noise in the receiver. , Transmission signal phase noise is reduced, so that each receiver has the effect of frequency synchronization and phase noise removal in the same state.

In the STL receiver 3, the broadcast wave I
The STL signal obtained by frequency-multiplexing the F signal, the FM reference signal, and the pilot carrier cancels noise in a non-divided state and is relayed as a relay IF signal to the next slave station / relay station. There is an effect that the apparatus can be simplified without providing a multiplexing unit in the transmitter 4.

Also, with respect to the tracking error and the signal deterioration caused by the superposition of the phase noise which occur at the time of the PLL reproduction of the local oscillation signal which is a problem in the case of the IF relay, the STL receiver 3 of the master station or the slave station / relay is not required. By reducing the influence of the local oscillation signal noise by the local noise canceller 33 inside the TTL receiver 6 of the station, there is an effect that the multistage relay can be performed without impairing the quality of the transmission signal.

Further, according to the digital TV broadcast transmission method and the terrestrial digital TV broadcast system of the present invention, the STL transmitter 2 in the studio frequency-multiplexes the FM reference signal and the pilot carrier with the broadcast wave IF signal and transmits the signal. On the receiving side, frequency synchronization and noise cancellation of the broadcast IF signal and the relay IF signal are performed using the FM reference signal and the pilot carrier, so that accuracy is ensured outside the signal band of the broadcast IF signal. Although the signal is transmitted, the required bandwidth as a whole may be 8 MHz in the case shown in FIG. 10, for example, and there is an effect that the transmission quality can be improved without significantly increasing the required bandwidth.

[0091]

According to the terrestrial digital TV broadcast transmission method of the present invention, an FM reference signal obtained by FM-modulating a reception-side frequency reference signal used for frequency synchronization and noise removal on the reception side in a studio, a pilot carrier, Broadcast wave IF
Frequency multiplexing with a signal, frequency-converted and transmitted as an STL signal, a transmitting station receives an STL or a TTL signal from a preceding transmitting station, frequency-converts the signal, generates a reception IF signal, and Acquires the receiving-side frequency reference signal from the FM reference signal in the signal, performs frequency synchronization and noise reduction of the broadcast wave IF signal using the receiving-side frequency reference signal and the pilot carrier, and transmits it to the television receiver as a broadcast wave. At the same time, the reception IF signal is frequency-synchronized and denoised using the reception-side frequency reference signal and the pilot carrier to form a relay IF signal, and the relay IF signal is frequency-converted to a subsequent transmission station as a TTL signal. Since the relay transmission is used, the FM transmitted from the studio at each transmitting station
According to the receiving-side frequency reference signal obtained from the reference signal, frequency synchronization is performed with high precision, and further, while removing phase noise superimposed in the transmission process, while transmitting the broadcast IF signal, relay-transmitting the relay IF signal, In addition to maintaining high frequency accuracy, the transmission quality is also improved, and it is possible to cope with multi-stage relay, so that there is an effect that relay transmission can be performed while maintaining sufficient performance as a whole.

Further, according to the terrestrial digital TV broadcasting transmission system of the present invention, the studio uses the receiving-side frequency reference signal used for frequency synchronization and noise removal on the receiving side by FM.
After frequency-multiplexing the modulated FM reference signal, the pilot carrier and the broadcast wave IF signal,
A studio that transmits as a TL signal, and the transmitting station is S
TL or a TTL signal from a preceding transmitting station is received and frequency-converted to generate a reception IF signal.
Acquiring the reception-side frequency reference signal from the M reference signal, performing frequency synchronization and noise removal of the broadcast IF signal using the reception-side frequency reference signal and the pilot carrier, and transmitting the broadcast wave to a television receiver as a broadcast wave, Using the reception-side frequency reference signal and the pilot carrier, perform frequency synchronization and noise removal of the reception IF signal to obtain a relay IF signal,
Since the relay station IF is frequency-converted and the transmission station relays and transmits as a TTL signal to a subsequent transmission station, each transmission station has high accuracy in accordance with the reception-side frequency reference signal obtained from the FM reference signal transmitted from the studio. While transmitting the broadcast IF signal while removing the phase noise superimposed in the transmission process,
While relaying signals, maintaining high frequency accuracy,
The transmission quality is also improved, so that it is possible to cope with multi-stage relay, and there is an effect that relay transmission can be performed while maintaining sufficient performance as a whole.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a terrestrial digital TV broadcasting system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of an STL transmitter in the terrestrial digital TV broadcasting system of the present invention.

FIG. 3 is a characteristic diagram showing a frequency characteristic of a signal in each unit inside the STL transmitter according to the present invention.

FIG. 4 is a block diagram showing an internal configuration of an STL receiver or a TTL receiver in the digital terrestrial TV broadcasting system of the present invention.

FIG. 5 is a basic configuration diagram for explaining the operation principle of local noise cancellation.

FIG. 6 is a characteristic diagram showing frequency characteristics of each part of the basic configuration of local noise cancellation.

FIG. 7 is a characteristic diagram showing a frequency characteristic of a signal in each part inside the STL receiver or the TTL receiver of the present invention.

FIG. 8 is a block diagram of a TTL transmitter or an internal configuration of the TTL transmitter in the terrestrial digital TV broadcasting system of the present invention.

FIG. 9 is a characteristic diagram showing a frequency characteristic of a signal in a TTL transmitter of the present invention or each unit in the TTL transmitter.

FIG. 10 is an explanatory diagram showing an example of a frequency characteristic (spectrum) and an example of an emission mask of an STL / TTL signal of the present invention.

[Explanation of symbols]

1 ... BST-OFDM modulator, 2 ... STL transmitter,
3 STL receiver, 4 TTL transmitter, 5 Broadcast transmitter, 6 TTL receiver, 7 TTL transmitter, 8
... Broadcasting transmitter, 9 ... TV receiver, 21 ... Pilot carrier generation unit, 22 ... Reception-side frequency reference signal generation unit, 23 ... FM reference signal generation unit, 24 ... OW generation unit, 25 ... Frequency multiplexing unit, 26: transmission frequency conversion unit, 27: power amplification unit, 30: reception F / E unit, 31
... Reception IF unit, 32 ... Frequency multiplex division unit, 33 ... Local noise canceller, 34 ... Pilot carrier reproduction unit, 35 ... Reception-side frequency reference signal reproduction unit
36: High stability local oscillation signal reproducing unit, 37: Broadcast wave IF signal reproducing unit, 38: Relay wave IF signal reproducing unit, 3
9 OW reproduction unit, 40 transmission frequency conversion unit, 41
Power amplifying unit, 50: distributor, 51: band-pass filter, 52: limiter amplifier, 60: local oscillator, 6
1: frequency converter, 62: band-pass filter, 63
... delay compensator, 70 ... frequency converter, 71 ... band-pass filter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 7/08 H04N 7/08 Z 7/081 F term (Reference) 5C025 AA01 AA06 5C056 FA01 FA05 FA20 GA09 GA11 GA14 GA20 HA01 HA04 5C063 AA20 AB03 AB06 CA14 CA23 DA07 5K022 AA11 AA21 AA31 DD01 DD13 DD18 DD19 DD21 DD31

Claims (7)

[Claims] 1. A studio modulates broadcast data to generate a broadcast wave IF signal, frequency-converts the broadcast wave IF signal and transmits it as an STL signal, and at a transmitting station, the STL signal or a preceding transmitting station. Receiving the TTL signal from the receiver, frequency-converting it to generate a reception IF signal, transmitting a broadcast wave IF signal included in the reception IF signal to a television receiver as a broadcast wave, and transmitting the IF signal to a relay wave IF. In the terrestrial digital TV broadcasting transmission method of converting the frequency as a signal and relaying the TTL signal to a subsequent transmitting station, the studio generates a receiving-side frequency reference signal and a pilot carrier used for frequency synchronization and noise removal on the receiving side. Then, a broadcast wave IF signal is frequency-multiplexed with the reception-side frequency reference signal and the pilot carrier, and the frequency is converted to an STL signal. The transmitting station outputs a relay IF signal by performing frequency synchronization and noise removal of the received IF signal using a receiving-side frequency reference signal and a pilot carrier in the received IF signal, and outputting the received signal. A broadcast wave IF in the received IF signal using the side frequency reference signal and the pilot carrier.
A terrestrial digital TV broadcast transmission method, comprising: synchronizing a signal and removing noise to output a broadcast IF signal. 2. A method for frequency synchronization and noise removal of a broadcast IF signal or a relay IF signal using a reception-side frequency reference signal and a pilot carrier, comprising the steps of: The IF signal is divided into two branches, and one of the branch signals is frequency-converted by a local oscillation signal having a small phase noise based on the reception frequency reference signal. A frequency synchronization and noise elimination method that obtains the following phase noise and frequency-converts the signals output from the two branches to synchronize with the local oscillation signal and cancel the phase noise. Item 1
The terrestrial digital TV broadcast transmission method described in the above. 3. In a studio, a receiving-side frequency reference signal is subjected to wide-band FM modulation to generate an FM reference signal, the FM reference signal is frequency-multiplexed with a broadcast IF signal, and transmitted. 3. The terrestrial digital TV broadcast transmission method according to claim 1, wherein frequency synchronization and noise removal of a broadcast IF signal and a relay IF signal are performed using a reception-side frequency reference signal obtained from the reference signal. . 4. A terrestrial digital apparatus comprising: a studio; a plurality of television receivers; and a plurality of transmitting stations for relaying a signal transmitted from the studio in multiple stages and transmitting a broadcast wave to the television receiver during the relay. In the TV broadcasting system, the studio modulates broadcast data to generate a broadcast IF signal, generates a receiving-side frequency reference signal and a pilot carrier used for frequency synchronization and noise removal on a receiving side, and A reference signal is subjected to wideband FM modulation to generate an FM reference signal, and the broadcast wave IF signal and the FM
A studio for frequency-multiplexing a reference signal and the pilot carrier, converting the frequency, and transmitting the converted signal as an STL signal;
A TL signal is received, frequency-converted to generate a reception IF signal, and a frequency synchronization and noise of a broadcast wave IF signal in the reception IF signal using a reception-side frequency reference signal and a pilot carrier in the reception IF signal. The signal is transmitted to a television receiver as a broadcast wave, and the reception IF signal is frequency-synchronized and noise-removed by using the reception-side frequency reference signal and the pilot carrier, so that the relay wave I is removed.
A terrestrial digital TV broadcast system, which is a transmitting station that relays the relay IF signal as a TTL signal to a subsequent transmitting station as an F signal. 5. A studio that digitally modulates broadcast data to be transmitted to generate a broadcast wave IF signal, and generates a reception-side frequency reference signal and a pilot carrier used for frequency synchronization and noise removal on the reception side. An STL for generating an FM reference signal obtained by performing wideband FM modulation on the reception-side frequency reference signal, frequency-multiplexing the broadcast IF signal, the FM reference signal, and the pilot carrier, performing frequency conversion, and transmitting the STL signal; And a transmitting station, wherein each transmitting station receives the STL signal or T from the preceding transmitting station.
A TL signal is received, frequency-converted to generate a reception IF signal, and a frequency synchronization and noise of a broadcast wave IF signal in the reception IF signal using a reception-side frequency reference signal and a pilot carrier in the reception IF signal. Remove the broadcast wave IF
A signal is reproduced and output, and the reception IF is used by using the reception-side frequency reference signal and the pilot carrier.
An STL / TTL receiver that reproduces and outputs a relay IF signal by performing frequency synchronization and noise removal of a signal, a broadcast transmitter that generates and transmits a broadcast radio wave from the broadcast IF signal, 5. The terrestrial digital TV broadcasting system according to claim 4, further comprising a TTL transmitter for frequency-converting the wave IF signal and relay-transmitting the converted signal to a subsequent transmitting station as a TTL signal. 6. A modulator in a studio, which digitally modulates broadcast data using a high-precision reference signal to generate a broadcast IF signal, and outputs the broadcast IF signal and the reference signal. A studio STL transmitter, a pilot carrier generating means for generating a pilot carrier used for frequency synchronization and noise elimination on the receiving side, and a receiving side frequency reference signal used for frequency synchronization and noise elimination on the receiving side. Receiving-side frequency reference signal generating means for generating based on a reference signal from a modulator, broadband FM modulation of the receiving-side frequency reference signal to generate an FM reference signal, and broadcasting from the modulator Frequency multiplexing means for frequency-multiplexing a wave IF signal, the pilot carrier, and the FM reference signal; An STL transmitter having a transmission frequency converting means for transmitting a TTL signal with wavenumber conversion, transmission stations STL / TTL receiver, ST from the studio
Receiving means for receiving an L signal or a TTL signal from a transmitting station at a preceding stage, performing frequency conversion to generate a reception IF signal, dividing the reception IF signal into components of the reception IF signal and components of a pilot carrier; Frequency multiplexing / division means for outputting a component of the FM reference signal; a receiving-side frequency reference signal obtained from the component of the FM reference signal; a pilot carrier being reproduced from the pilot carrier component; Performs frequency synchronization and noise removal of the broadcast wave IF signal to reproduce and output the broadcast wave IF signal, and uses the reception-side frequency reference signal and the pilot carrier to perform frequency synchronization and noise removal of the reception IF signal. And an STL / TTL receiver having local noise canceling means for reproducing and outputting a relay IF signal. Terrestrial digital TV broadcasting system according to claim 5,. 7. A local noise canceling means of an STL / TTL receiver, a pilot carrier reproducing means for reproducing a pilot carrier from a pilot carrier component, and a receiving-side frequency reference signal from an FM reference signal component. Receiving side frequency reference signal reproducing means for obtaining; high stability local oscillation signal reproducing means for generating a high stability local oscillation signal from the receiving side frequency reference signal; and Converting the broadcast wave IF signal, delay-correcting the reproduced pilot carrier so that the delay becomes equivalent to the delay, and frequency-converting the delay-corrected signal with the reproduced pilot carrier. A broadcast wave IF signal reproducing means for reproducing a broadcast wave IF signal by restricting a required band component as an IF signal; The components of the received IF signal inputs a signal obtained by frequency conversion by the local oscillation signal in the signal reproducing means,
The reproduced pilot carrier is subjected to delay correction so that the delay becomes equivalent, the frequency of the delay-corrected signal is converted by the reproduced pilot carrier, and limited to a required band component as a relay IF signal. Te relay wave IF
7. The terrestrial digital TV broadcasting system according to claim 6, wherein said terrestrial digital TV broadcasting system is a local noise canceling unit having a relay wave IF signal reproducing unit for reproducing a signal.