JPH08186811A - Satellite broadcast receiver - Google Patents

Abstract

PURPOSE: To provide a satellite broadcast receiver suppressing an audio signal and a video signal stably and well balanced when a received C/N ratio is low. CONSTITUTION: The receiver is provided with a BPF 1 to be connected to a broadcast satellite reception antenna, a mixer 2, PLL detection circuit 3, AGC circuit 4, FM demodulation circuit 5, local oscillation circuit 6, LPF 7, de-emphasis circuit 8, video amplifier circuits 9, 11 and a clamp circuit 10, and also with a QPSK demodulation circuit 13, differential conversion circuit 14, synchronization detection circuit 15, timing circuit 16, descramble circuit 17, de-interleave circuit 18, error check correction circuit 19, counter 20, suppression timing circuit 21 and output suppression circuit 22. Thus, even in the case of receiving a signal with a low C/N, outputs of a voice signal and a video signal are suppressed stably and with excellent balance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite broadcast receiver.

[0002]

2. Description of the Related Art A satellite broadcast receiving device is designed to fly over the equator 36,0.
From the broadcasting satellite on the geostationary orbit of 00 km, the Ku band (12
It is a device that receives broadcast radio waves transmitted in the GHz band) and reproduces audio signals and video signals from the broadcast radio waves, and is now widely used in general as satellite broadcasting becomes widely used.

Broadcast radio waves used in satellite broadcasting are
Due to the restriction of the transmission power of the broadcasting satellite on the geostationary orbit and the restriction of the long-distance radio wave propagation accompanying the geostationary altitude, the reception power becomes extremely weak, so that the reception antenna and BS-
IF converter (generally, these receiving antennas and BS-IF converters are integrated to eliminate loss due to antenna lines and reduce noise, and both are called a satellite broadcasting receiving antenna. Low noise / high gain (for example, noise figure: NF = 0.7 dB,
Antenna gain: G _r = 55 dB) is used, but due to various reception conditions including rainfall and atmospheric conditions, and problems due to the directional characteristics of the receiving antenna,
The reception state of the satellite broadcast receiving device is greatly influenced.

Generally, when the reception condition is completely deteriorated or the reception condition is not satisfied, for example,
If the antenna line of the broadcasting satellite receiving antenna is disconnected, there is no satellite broadcasting, or if the broadcasting radio wave is blocked by some obstacle such as a flying object, the reception level will drop completely. , Both the audio signal and video signal levels are completely suppressed by asynchronous suppression processing, etc., but this is not a problem, but the problem in lowering the reception level is that normal reception and complete reception as described above. This is a transition state of the reception level during the state in which the level is suppressed. This reception level transition state is caused by, for example, a change in rainfall conditions, but in this case, the reception condition deteriorates due to a continuous or intermittent transition of the reception level, and the audio signal and the video signal are transmitted. The quality of the signal deteriorates, and as a result, the generation of noise and a significant change in the noise level cause discomfort to the viewer.

As a method for solving such a problem, conventionally, there is an apparatus example (referred to as a first conventional example) disclosed in Japanese Patent Laid-Open No. 64-44691 (Japanese Patent Application No. 62-202085). As in the satellite receiver
If the reception level is judged to be less than the reference level, the reception level and the reference level required for normal audio and video signals are compared and judged by the output voltage of the circuit. It is considered that the output level of the signal is controlled so that the viewer does not feel uncomfortable due to the generation of noise. Also, "TV technology"
In another example of the device (referred to as the second conventional example) shown in "November 1990 issue", the high frequency noise component included in the received signal is detected from the received output after FM demodulation through a high band amplifier (9 MHz BPF). , C when receiving broadcast waves
A method of detecting the / N ratio (abbreviation of signal-to-noise ratio: Carr-ier to Noise Ratio) and controlling the levels of the audio signal and the video signal based on the result is adopted.

The above-mentioned first and second conventional examples will be described below with reference to the drawings. FIG. 3 is a block diagram showing the configuration of the first conventional example, which is described in the above-mentioned Japanese Patent Laid-Open No. 64-64-
44691 (Japanese Patent Application No. 62-202085)
It is an example of an apparatus related to the proposal by. This conventional example is shown in FIG.
, A BPF 31 connected to a broadcast satellite receiving antenna (not shown), a mixer 32, and a PLL.
Detection circuit 33, AGC circuit 34, FM demodulation circuit 35
And a local oscillation circuit 36.

In FIG. 3, the intermediate frequency signal 101 sent from the broadcasting satellite receiving antenna is 1.0 to 1.3G.
A local oscillation circuit that is input to a mixer 32 through a BPF 31 that extracts a Hz signal and that is frequency-controlled by a detection output of a PLL detection circuit 33 that is provided so as to be synchronized with a desired channel of BS-1 to 15ch (channel). Three
Mixed with the oscillating output of 6, the second of 402.78MHz
The intermediate frequency signal is extracted, and the second intermediate frequency signal is AG
The voltage level is input to the C circuit 34, and its voltage level is maintained at a predetermined level value and output. The second intermediate frequency signal output from the AGC circuit 34 whose voltage level is stabilized is input to the FM demodulation circuit 35, FM demodulated and output as a demodulation output signal, and at the same time, a predetermined output suppression circuit (illustrated). Output suppression control signal 104
Is sent as In this case, when the received signal is at a low level and the level of the second intermediate frequency signal output from the AGC circuit 34 is lower than a predetermined level, the output levels of the audio signal and the video signal are reduced by the output suppression. In a circuit (not shown), suppression control is performed by the output suppression control signal 104.

FIG. 4 is a block diagram showing the configuration of another second conventional example, which is referred to in the above-mentioned "TV Technology '90.
It is another example of the device seen in "Monthly issue". This conventional example is a BPF connected to a broadcasting satellite receiving antenna (not shown).
41 and 49, a mixer 42, and a PLL detection circuit 43
An AGC circuit 44, an FM demodulation circuit 45, a local oscillation circuit 46, a level adjustment circuit 47, an amplification circuit 48,
It is configured to include a C / N detection circuit 50 and a gain adjustment circuit 51. The difference from the conventional example of FIG. 3 is that a level adjusting circuit 47, an amplifying circuit 48, a BPF 49, a C / N detecting circuit 50, and a gain adjusting circuit 51 are newly added, and the BPF 41, the mixer 42, The operations of the PLL detection circuit 43, the AGC circuit 44, the FM demodulation circuit 45, and the local oscillation circuit 46 are the same as those in the above-mentioned conventional example. In FIG. 4, the demodulation output of the FM demodulation circuit 45 has an appropriate demodulation output level via the level adjusting circuit 47 and the amplifying circuit 48 according to the performance of the satellite receiving antenna, the receiving environment such as the installation location of the receiving device, and the like. It is adjusted to a proper signal level. The output of the amplifier circuit 48 passes through a BPF 49 having a frequency bandwidth corresponding to a frequency range of about 9 MHz, that is, a frequency range not including the audio signal and the video signal, and the noise level included in the output of the amplifier circuit 48 is increased. It is extracted and output. This extracted noise output is C /
The signal is input to the N detection circuit 50, level-controlled by the gain control circuit 51, set to an appropriate noise level, and sent as an output suppression control signal 104 to a predetermined output suppression circuit (not shown). This output suppression control signal 104 suppresses the signal output including the audio signal and the video signal when the noise signal level included in the received signal does not exceed the predetermined allowable amount in the output suppression circuit. Is a control signal that operates as described above.

In the conventional satellite broadcast receiving apparatus described above, the means for generating the output suppression control signal for suppressing the signal output including the audio signal and the video signal according to the reception environment is the case of the first conventional example. Detects the carrier wave level at the time of receiving the broadcast wave and generates the output suppression control signal,
Further, in the case of the second conventional example, the output suppression control signal is generated by detecting the noise level. For these conventional examples, for example, as introduced in "Radio Technology JULY'88", in the case of satellite broadcasting, the S / N ratio of the video signal of the receiver is a broadcast received by a parabolic antenna. The fact that it is determined by the C / N ratio of radio waves is used. Above "Radio technology JULY'88 pp.124-126"
In the example described in 1), when the value is less than “3” by the five-level evaluation method of the image quality, that is, when C / N = 7 dB or so, the interference due to the noise level is large. The audio signal and the video signal are suppressed by the result of detecting the C / N.

[0010]

In the above-mentioned conventional satellite broadcast receiver, the "radio technology JULY'88, p" is used.
As shown in the example described in "p.124", receive C /
When the N ratio decreases, the S / N ratio of the video signal rapidly decreases non-linearly from a certain level. In addition, the reception C / N ratio is affected by the type of antenna to be received (antenna gain and noise figure (NF), etc.) and the reception situation (presence or absence of obstacles in the radio wave propagation path, reception location, etc.). Optimal reception C / for suppressing signal and video signal
Determining the N ratio is difficult. For this reason, there is a drawback in that, depending on the reception environment, a situation may occur in which "a signal is suppressed even though it is still sufficiently visible", or "a noise is so severe that it cannot be viewed".

Further, the S / N ratio against the deterioration of the received C / N ratio
There is a problem due to the correlation between the ratio and the increased error rate in the voice PCM signal. That is, when the reception C / N ratio deteriorates, an error easily occurs in the audio PCM signal, but unlike the video signal, in the case of the audio signal, BCH (Bose-C
Haudhuri-Hocuenghem) code has the function of correcting a single error by itself (The Institute of Electronics, Information and Communication Engineers A Vol.J
73-A NO.2 pp.196-202,203-208,1990.2).
However, when the level of the received C / N ratio decreases and the double error increases, the error can be detected but the error cannot be corrected. Therefore, the previous value interpolation (previous state) is usually performed. However, if the error situation is further deteriorated (continuous double error occurs), it becomes impossible to normally reproduce the voice and noise is generated. The noise signal at this time is randomly generated from the minimum value to the maximum value of the voice signal level, unlike the white noise type noise such as “shear” or “za” in the ground wave at low C / N ratio. In order to do so, it can be heard as an extremely unpleasant noise such as "burr."

Although the probability of occurrence of double error in such a voice PCM signal is proportional to the received C / N ratio as shown in Japanese Patent Application No. 4-004385, it is analog and digital. Due to the difference in the system, the above-described proportional relationship between the S / N ratio of the video signal and the received C / N ratio cannot be established. That is, in the above-described first and second conventional examples, "the image appears to be normal, but the audio output is noisy, and the audio output is suppressed randomly", or vice versa. There is a situation in which "the image is disturbed by noise and cannot be seen, but the voice output is normally output although the noise is included." Particularly, this situation occurs around the reception C / N = 7 dB, and the image / audio reproduction capability of the receiver is unbalanced. This is more remarkable than in the case of terrestrial broadcasting in which both the image and the sound are the same analog system in the related art, and further in the satellite broadcasting other than the first and second conventional examples. , Viterbi decoding, etc., which has strong error correction capability at low carrier level and low C / N ratio (see IEICE Journal A Vol.J73-A NO.2 pp.218-224,1990.2). In the communication / broadcasting used, there is a drawback that the above-mentioned problems occur more remarkably.

The present invention includes the first and second aspects shown above.
It is an object of the present invention to provide a satellite broadcast receiving device capable of effectively suppressing low C / N ratio noise by coping with the problem in the conventional example.

[0014]

SUMMARY OF THE INVENTION A satellite broadcast receiving apparatus of the present invention includes a reception demodulation section for receiving an intermediate frequency signal output from an antenna for receiving a satellite broadcast wave and performing FM demodulation, and an output from the reception demodulation section. An FM demodulated signal that is input, a video signal processing unit that extracts and outputs a video signal included in the FM demodulated signal, and an FM that is output from the reception demodulation unit.
The demodulated signal is input, the digital audio signal included in the FM demodulated signal is extracted, and the digital audio signal is QP
QPSK that demodulates SK and outputs the first audio PCM signal
A demodulation unit, a reference timing generation unit that inputs the first audio PCM signal, generates and outputs a frame reference timing signal of the first audio PCM signal, and inputs the first audio PCM signal. , The error-removed second voice PCM signal is extracted and output through signal processing on the first voice PCM signal, and the error occurrence frequency associated with the first voice PCM signal is detected. An output level of the second audio PCM signal and the video signal is detected through the frame reference timing signal with reference to the audio signal processing unit that detects and outputs the error occurrence frequency output from the audio signal processing unit. And a video control signal for generating and outputting a signal suppression control signal for suppressing control of the frame reference signal. The timing signals and the signal suppression control signal, and said second audio PCM signal and output suppression circuit unit and outputting the suppression signal level of the video signal to a predetermined level, comprising at least a.

The audio signal processing unit de-interleaves the descramble circuit for descrambling the first audio PCM signal and the audio PCM signal output from the descramble circuit, and outputs the third audio signal. PC
A deinterleave circuit for extracting and outputting the M signal, and a third audio PC output from the deinterleave circuit
An error in which the M signal is input, the double error occurrence frequency of the third voice PCM signal is detected and output, and the second voice PCM signal from which the double error is removed is generated and output. A detection / correction circuit, wherein the suppression signal generator refers to the double error occurrence frequency, and refers to the double error occurrence frequency, and outputs the number of error occurrences corresponding to the double error occurrence frequency via the frame reference timing signal. A counter circuit that counts and outputs the second audio PCM signal and the video when the count value of the number of error occurrences output from the counter circuit exceeds a predetermined predetermined count value. And a suppression timing control circuit that generates and outputs a pair of suppression control signals for suppressing the output level of the signal at preset predetermined time intervals. It may be.

Further, the audio signal processing section may include a descrambling circuit for descrambling the first audio PCM signal and an interleave for the audio PCM signal output from the descrambling circuit, and the third
Deinterleave circuit for extracting and outputting the audio PCM signal of
Voice PCM signal is input to detect and output the double error occurrence frequency of the third voice PCM signal, and the second voice PCM signal from which the double error is removed is generated and output. An error detection / correction circuit is provided, and the suppression signal generation unit refers to the double error occurrence frequency, and generates an error occurrence corresponding to the double error occurrence frequency via the frame reference timing signal. A counter circuit that counts and outputs the number of times, and when the count value of the number of error occurrences output from the counter circuit exceeds a predetermined predetermined count value, the second audio PCM signal and the A suppression control circuit that generates and outputs a suppression control signal for simultaneously suppressing the output level of the video signal may be configured.

[0017]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. As shown in FIG. 1, in the present embodiment, a BPF 1, a mixer 2, a PLL detection circuit 3, A that is connected to a broadcast satellite reception antenna (not shown) to form a reception demodulation unit.
A GC circuit 4, an FM demodulation circuit 5 and a local oscillator circuit 6,
An LPF 7, a de-emphasis circuit 8, a video amplifier circuit 9, a clamp circuit 10 and a video amplifier circuit 11 which form a video signal processing unit, and a BPF 12 which forms a QPSK demodulation unit,
A QPSK demodulation circuit 13 and a differential conversion circuit 14, a synchronous detection circuit 15 and a timing circuit 16 forming a reference timing generation unit, a descrambling circuit 17, a deinterleave circuit 18, and an error detection / correction forming an audio signal processing unit. The circuit 19, a counter circuit 20 and a suppression timing control circuit 21 that form a suppression control unit, and an output suppression circuit 22 that forms an output suppression circuit unit are configured. In addition, in FIGS. 2A, 2B and 2C, P
It is a figure which shows the frame structural example of a CM audio signal.

In FIG. 1, an intermediate frequency signal 101 transmitted from a broadcasting satellite receiving antenna (not shown) is
The signal is input to the mixer 2 through the BPF 1 that extracts a signal of 1.0 to 1.3 GHz, and the frequency is controlled by the detection output of the PLL detection circuit 3 that is provided so as to be tuned to a desired channel in BS-1 to 15 ch. The second intermediate frequency signal of 402.78 MHz is extracted and output by being mixed with the oscillation output of the local oscillation circuit 6, and is input to the AGC circuit 4 to maintain the voltage level of the second intermediate frequency signal at a predetermined level. Is output in the state of being The second intermediate frequency signal output from the AGC circuit 4 whose voltage level is stabilized is input to the FM demodulation circuit 5, FM demodulated and output, divided into the LPF 7 and the BPF 12, and input. LPF7 is an LPF with a frequency of 4.5 MHz
That is, the video signal included in the FM demodulated signal is extracted and output through the LPF 7, and is input to the de-emphasis circuit 8. In the de-emphasis circuit 8, the emphasis applied at the time of sending the broadcast signal is released, and the output video signal is amplified by the video amplifier circuit 9 and input to the clamp circuit 10. Then, the video signal output from the clamp circuit 10 is input to the output suppression circuit 22.

On the other hand, the BPF 12 has a frequency of 5.7 MH.
a BPF of z, and the BPF 12 extracts the QPSK audio signal included in the FM demodulated signal and outputs the QPSK audio signal.
It is input to the QPSK demodulation circuit 13 and demodulated. QPS
The in-phase component I and the quadrature component Q demodulated and output in the K demodulation circuit 13 are input to the differential conversion circuit 14 and converted into a 2.048 Mbit / S audio PCM signal and output, and the synchronization detection circuit 15 And descrambling circuit 1
7 is input. In the sync detection circuit 15, the frame sync signal of the audio PCM signal is detected.
2A shows the frame structure of the 2.048 Mbit / S voice PCM signal, and FIGS. 2A and 2B show the frame structure of frame 1 in the A mode and the B mode, respectively. , The frame detection signal corresponding to each frame is detected and input to the timing circuit 16 in the synchronization detection circuit 15. The timing circuit 16 receives the frame synchronization signal, generates a frame reference timing signal based on the timing of the frame synchronization signal, outputs the frame reference timing signal, and inputs the frame reference timing signal to the output suppression circuit 22 and the counter circuit 20. Entered in.

On the other hand, the 2.048 Mbit / S audio PCM signal input to the descramble circuit 17 is scrambled and interleaved at the time of transmitting the broadcast signal via the descramble circuit 17 and the deinterleave circuit 18. Is released and is output as audio P
The CM signal is input to the error detection / correction circuit 19 and the output suppression circuit 22. The error detection / correction circuit 19 uses the voice P
BCH (63,56) SEC used for CM signal
(Single error correction) -A circuit that detects a double error using the property of a DED (double error detection) code and outputs a double error flag indicating the error occurrence frequency. The error flag is input to the counter circuit 20. In the counter circuit 20, the number of error occurrences indicated by the double error flag is counted based on the frame reference timing signal sent from the timing circuit 16, and the count value is the suppression timing control circuit 2
Input to 1. The suppression timing control circuit 21 outputs a suppression timing signal for suppressing the signal levels of the audio PCM signal and the video signal at a predetermined time interval when the count value exceeds a preset value, It is input to the output suppression circuit 22. In the output suppression circuit 22, the video signal output from the video amplifier circuit 11, the frame reference timing signal output from the timing circuit 16, the audio PCM signal output from the deinterleave circuit 18, and the output from the suppression timing control circuit 21. In response to the reception of the suppression timing signal or the like, the signal levels of the audio PCM signal and the video signal are individually suppressed by the suppression timing signal at predetermined time intervals according to the reception environment and the like, The signal 102 and the audio signal 103 are output.

In the above-described embodiment, the suppression control section includes the counter circuit 20 and the suppression timing control circuit 2.
1 and the suppression timing control circuit 21 outputs the suppression timing signal to output the audio PCM.
Although the circuit is formed so as to suppress the signal level of the signal and the video signal at a predetermined time interval, as another embodiment of the present invention, a suppression timing control circuit forming the suppression control section. 21 is replaced with a suppression control circuit irrelevant to the timing control action, and the suppression control signal output from the suppression control circuit simultaneously suppresses the signal levels of the audio PCM signal and the video signal in the output suppression circuit 22. It is also possible to form the circuit as described above and output as the video signal 102 and the audio signal 103.

Generally, the S / N ratio of a video signal and the received C / N
The ratio, the error occurrence frequency in the voice PCM signal, and the received C / N ratio have a correlation with each other, but at a low C / N ratio (= around 7 dB) when the reception situation begins to become unstable, both The correlation of is lost. For example, according to the above-mentioned “Radio Technology, JULY'88, pp.124”,
When C / N is 10 dB or more, 1 in C / N ratio
The S / N ratio of the video signal deteriorates by 1 dB with respect to the deterioration of dB, but when the C / N ratio is 7 dB or less, the C / N ratio decreases.
The S / N ratio of the video signal is 10 with respect to the deterioration of the ratio of 1 dB.
It has deteriorated near dB. On the other hand, although the error occurrence frequency in the voice PCM signal depends on the error correction method, for example, it is known that the relationship between the C / N ratio and the error occurrence frequency until the frame synchronization is about to be lost holds a substantially constant relationship. Has been. As described above, generally, if the processing result for two uncorrelated signals is controlled by only one signal, it may not be a perfect control method, but a more stable characteristic at a low C / N ratio is obtained. Is controlled by the voice PCM signal holding the signal, and the two signals are controlled in a fixed timing relationship, a more stable characteristic can be obtained as compared with the conventional method. In the present invention,
When suppressing the video signal output at a C / N ratio lower than the conventional one, it is necessary to take measures to cope with the deterioration of the S / N ratio of the video signal. In this case, for example, "TV technology '89. /Vol.37, p.57 ”can be improved by adopting an adaptive video noise reduction circuit.

That is, according to the present invention, according to the reception environment, even in the state of C / N = 7 dB, where there is no correlation between the output noise levels of the audio signal and the video signal,
Collecting both audio and video signal output,
The effect that it can be controlled effectively and stably is obtained.

[0025]

As described above, the present invention is applied to a broadcasting satellite receiving apparatus, and at the time of reception with a low C / N ratio, a control action by an audio PCM signal that maintains stable characteristics, By controlling the two signal levels including the audio PCM signal and the video signal while maintaining a constant timing relationship, the signal output of the audio signal and the video signal can be suppressed in a stable and balanced manner. .

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing an example of a frame configuration of an audio signal in the present embodiment.

FIG. 3 is a block diagram showing a first conventional example.

FIG. 4 is a block diagram showing a second conventional example.

[Explanation of symbols]

 1, 12, 31, 41, 49 BPF 2, 32, 42 Mixer 3, 33, 43 PLL detection circuit 4, 34, 44 AGC circuit 5, 35, 45 FM demodulation circuit 6, 36, 46 Local oscillation circuit 7 LPF 8 De-emphasis circuit 9, 11 Video amplification circuit 10 Clamp circuit 13 QPSK demodulation circuit 14 Differential conversion circuit 15 Synchronization detection circuit 16 Timing circuit 17 Descramble circuit 18 Deinterleave circuit 19 Error detection / correction circuit 20 Counter circuit 21 Suppression timing control circuit 22 Output Suppression Circuit 47 Level Adjustment Circuit 48 Amplification Circuit 50 C / N Detection Circuit 51 Gain Adjustment Circuit

Claims (3)

[Claims] 1. A reception demodulation unit for inputting an intermediate frequency signal output from an antenna for receiving a satellite broadcast wave and performing FM demodulation, and an FM demodulation signal output from the reception demodulation unit for inputting the FM demodulation. A video signal processing unit which extracts and outputs a video signal included in the signal, and an FM demodulated signal output from the reception demodulation unit are input to extract a digital audio signal included in the FM demodulated signal, and the digital audio signal A QPSK demodulation unit that QPSK demodulates the signal and outputs a first audio PCM signal; and inputs the first audio PCM signal to generate and output a frame reference timing signal of the first audio PCM signal. A reference timing generator and the first voice PCM signal are input to input the first voice P.
Audio that extracts and outputs an error-free second audio PCM signal through signal processing on the CM signal, and detects and outputs an error occurrence frequency associated with the first audio PCM signal. A signal processing unit, and for controlling the output level of the second audio PCM signal and the video signal via the frame reference timing signal with reference to the error occurrence frequency output from the audio signal processing unit. A suppression control unit that generates and outputs a signal suppression control signal, the second audio PCM signal and the video signal are input, and the second audio PCM signal is generated by the frame reference timing signal and the signal suppression control signal. And an output suppression circuit section that suppresses the signal level of the video signal to a predetermined level and outputs the image signal. That satellite broadcast receiver. 2. The audio signal processing section descrambling the first audio PCM signal, and deinterleaving the audio PCM signal output from the descrambling circuit, thereby removing the third audio signal. A deinterleave circuit for extracting and outputting a PCM signal, and a third voice P output from the deinterleave circuit.
An error of inputting a CM signal, detecting and outputting a double error occurrence frequency of the third voice PCM signal, and generating and outputting the second voice PCM signal from which the double error is removed. A detection / correction circuit, wherein the suppression signal generator refers to the double error occurrence frequency, and refers to the double error occurrence frequency, and outputs the number of error occurrences corresponding to the double error occurrence frequency via the frame reference timing signal. A counter circuit that counts and outputs, and when the count value of the number of error occurrences output from the counter circuit exceeds a predetermined predetermined count value,
A suppression timing control circuit that generates and outputs a pair of suppression control signals for suppressing the output levels of the second audio PCM signal and the video signal at preset time intervals. The satellite broadcast receiving apparatus according to claim 1, comprising: 3. The audio signal processing unit, the descrambling circuit for descrambling the first audio PCM signal, and the interleave of the audio PCM signal output from the descrambling circuit for descrambling, A deinterleave circuit for extracting and outputting an audio PCM signal, and a third audio P output from the deinterleave circuit.
Error detection in which a CM signal is input, a double error occurrence frequency of the third voice PCM signal is detected and output, and a second voice PCM signal from which the double error is removed is generated and output. And a correction circuit, wherein the suppression signal generator refers to the double error occurrence frequency, and determines the number of error occurrences corresponding to the double error occurrence frequency via the frame reference timing signal. A counter circuit for counting and outputting, and when the count value of the number of error occurrences output from the counter circuit exceeds a predetermined predetermined count value,
2. A suppression control circuit that generates and outputs a suppression control signal for simultaneously suppressing and controlling the output levels of the second audio PCM signal and the video signal. The satellite broadcast receiver described.