JP4026677B2 - Site diversity switching detection method and satellite broadcast receiver with site diversity switching detection function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a site diversity switching detection method and a satellite broadcast receiver with a site diversity switching detection function that can be used on a digital satellite broadcast receiver to confirm on the receiving side that site diversity switching has been performed.
[0002]
[Prior art]
In digital satellite broadcasting, “ARIB STD-B20” BS digital broadcasting transmission / operation conditions, “ARIB STD-B21” BS digital broadcasting receiver, “ARIB TR-B15” BS digital operating regulations, Part 7 BS digital broadcasting transmission operation Rules have been established. According to this, in the case where it is expected that a line cannot be secured in the vicinity of one uplink broadcasting station in operation due to rain or the like, site diversity that switches to operation by another uplink broadcasting station is adopted. In this site diversity, it is desirable to minimize the influence of interruptions in video and audio due to switching of uplink broadcast stations as much as possible.
[0003]
In this specification, switching from one uplink broadcast station in operation to operation by the other uplink broadcast station is also referred to as site switching.
[0004]
However, if the sites are switched, the continuity of the signal input to the digital satellite broadcast receiver cannot be maintained even if the timings of the transmitted signals are matched in both uplink broadcast stations. For this reason, the video or audio decoded by the digital satellite broadcast receiver is interrupted.
[0005]
In order to reduce this instantaneous interruption as much as possible, it is only necessary to notify the digital satellite broadcast receiver in advance that an instantaneous interruption of the carrier occurs. For this reason, in the site diversity between the main station (one uplink broadcast station) and the substation (the other uplink broadcast station) performed in the broadcast apparatus of the uplink broadcast station, a switch instruction is given in the TMCC information. The bit is set, and the site is switched within the period of the N superframe immediately after the bit is set.
[0006]
[Problems to be solved by the invention]
However, when site diversity switching is performed, there has been no method for confirming in a digital satellite broadcast receiver whether or not switching has been performed normally with actual radio waves. For this reason, even if there is a momentary interruption in the received image and audio, it has not been possible to distinguish whether or not site switching has not been operated at a prescribed timing on the broadcast transmission side.
[0007]
The present invention relates to a site diversity switching detection method and a satellite broadcast receiver with a site diversity switching detection function capable of detecting with a digital satellite broadcast receiver whether or not site switching is operated at a specified timing on the broadcast transmission side. The purpose is to provide.
[0008]
[Means for Solving the Problems]
A site diversity switching detection method according to the present invention is a site diversity switching detection method for detecting in a digital satellite broadcast receiver whether or not site switching is operated at a specified timing on a broadcast transmission side, The super frame is counted from the output start, and the frame status signal indicating that the frame synchronization pattern is continuously detected during the super frame counting period predetermined in the counting, the carrier reproduction is normally performed. Site diversity switching detection when it is detected that at least one of the carrier reproduction status signal indicating that the error bit in the TMCC information is equal to or less than a predetermined number is temporarily interrupted. A signal is transmitted.
[0009]
A satellite broadcast receiver with a site diversity switching detection function according to the present invention is a digital satellite broadcast receiver that detects whether or not site switching is operated at a specified timing on the broadcast transmission side, and outputs a transmission switching signal. The super frame is counted from the start, and the detection means during the super frame counting period for detecting that the counting is within the predetermined super frame counting period, and that the frame synchronization pattern is continuously detected. Frame status signal generating means for generating a frame status signal to indicate, carrier reproduction status signal generating means for generating a carrier reproduction status signal indicating that carrier reproduction is normally performed, and error bits in TMCC information are predetermined. Generate TMCC status signal indicating that the number is less than TMCC status signal generation means, and detection means for detecting that at least one of the frame status signal, the carrier reproduction status signal, or the TMCC status signal is temporarily interrupted and sending a site diversity switching detection signal. Features.
[0010]
According to the site diversity switching detection method and the satellite broadcast receiver with a site diversity switching detection function according to the present invention, superframes are counted from the start of output of the transmission switching signal, and during the superframe counting period predetermined in the counting. In addition, a frame status signal indicating that frame synchronization patterns are continuously detected, a carrier reproduction status signal indicating that carrier reproduction is normally performed, or error bits in TMCC information are equal to or less than a predetermined number. When it is detected that at least one of the TMCC status signals indicating that it is interrupted, a site diversity switching detection signal is output. Therefore, the digital satellite broadcast receiver side can detect whether or not the site switching is operated at the specified timing on the broadcast transmission side by the site diversity switching detection signal. If it is detected that the site switching has been performed correctly, processing suitable for site diversity switching is performed in the subsequent stage of the digital satellite broadcast receiver. When it is determined that an incorrect switching has occurred, there are other problems. It is possible to minimize the influence on the received image and the sound by switching to a process suitable for the occurrence.
[0011]
In the site diversity switching detection method according to the present invention, the frame status signal may be an output signal of a retriggerable one-shot multivibrator that is triggered every time a frame synchronization pattern is detected. It may be a signal indicating that the phase error voltage for reproduction is within a predetermined threshold value.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a site diversity switching detection method according to the present invention will be described according to an embodiment.
[0013]
1 is a block diagram showing a configuration of a site diversity switching detection circuit to which a site diversity switching detection method according to an embodiment of the present invention is applied, and FIG. 2 is a digital diagram including the site diversity switching detection circuit shown in FIG. It is a block diagram which shows schematic structure of a satellite broadcast receiver.
[0014]
Prior to the description of the site diversity switching detection circuit in FIG. 1, the frame structure of the hierarchical transmission method used in digital satellite broadcasting will be described.
[0015]
As is well known, one super frame is composed of 8 frames as shown in FIG. 7A, and each frame is composed of a frame synchronization pattern W1, a transmission parameter, a modulation method, and control information as illustrated in FIG. 7B. TMCC (Transmission and Multiplexing Configuration Control) information for transmission multiplex configuration identification, etc., frame identification synchronization pattern W2 or W3 for identifying whether it is the first frame in the superframe, main signal, reference burst signal, main Signal, reference burst signal,..., Main signal, and reference burst signal. The frame identification synchronization pattern W2 is used for the first frame in the super frame, and the frame identification synchronization pattern W3 is used for the 2 to 8 frames. FIG. 7B shows the second frame.
[0016]
The modulation method of the main signal is trellis code 8PSK, QPSK or BPSK, the frame synchronization pattern W1, the frame identification synchronization patterns W2, W3, the TMCC information and the modulation method of the reference burst signal are BPSK, the frame synchronization pattern W1, the frame The identification synchronization patterns W2 and W3 are 32 symbols each (including 20 symbols of fixed bits), the TMCC information is 128 symbols, the main signal is 203 symbols, and the reference burst signal is 4 symbols. One frame is composed of 39936 symbols.
[0017]
The extension area in the TMCC information includes 5 bits for change instructions and 5 bits for transmission / reception control information as shown in FIG. The change instruction 5 bits are incremented by 1 each time a change occurs in the contents of TMCC information such as a site diversity instruction. In transmission / reception control information 5 bits, as shown in FIG. 8B, bit 4 indicates a transmission / reception switching signal, bit 3 is a main station transmission signal, and bit 2 is a substation transmission signal.
[0018]
FIG. 8C-1 shows bit 4 in the transmission / reception control information, and FIG. 8C-2 shows change instruction instruction 5 bits. At the time of site switching, the change instruction instruction 5 bit is incremented by 1 and a bit is set in bit 4 in the transmission / reception control information (bit 4 = 1), from when the bit is set, that is, from when a transmission switching signal is received, The site is switched in the super frame when the super frame (SF) is counted N times, and after performing site diversity, the bit 4 in the transmission / reception control information is lowered in the M super frame (bit 4 = 0). To be done. At present, N = 16 and M = 0 in FIG. 8C-1 are set.
[0019]
Instructing uplink from the main station by setting bit 3 in the transmission / reception control information, and instructing uplink from the substation by setting bit 2 in transmission / reception control information .
[0020]
Next, referring back to FIG. The received signal in the digital satellite broadcast receiver is supplied to the front-end tuner 21, tuned to a desired broadcast based on reception channel selection, converted to an intermediate frequency signal of an intermediate frequency that can be easily processed, and the baseband signals I and Q Demodulated. The demodulated baseband signals I and Q output from the front end tuner 21 are supplied to the A / D converter 22 for A / D conversion, and the A / D conversion output is supplied to the 8PSK / QPSK / BPSK demodulation circuit 23. , PSK demodulation is performed.
[0021]
The baseband signals I and Q before error correction PSK demodulated by the 8PSK / QPSK / BPSK demodulation circuit 23 are subjected to trellis / Viterbi decoding in the trellis / Viterbi decoding circuit 24, and the data subjected to trellis / Viterbi decoding is deinterleaved. The descramble circuit 25 performs deinterleaving and descrambling, and the Reed-Solomon decoding circuit 26 performs Reed-Solomon decoding and outputs the result.
[0022]
In the digital satellite broadcast receiver, from the frame status signal indicating that the frame synchronization signal is normally detected in the 8PSK / QPSK / BPSK demodulation circuit 23 and the carrier reproduction status signal indicating that the carrier reproduction is normally performed. And a TMCC status signal and TMCC information indicating that an error bit is equal to or less than a predetermined number of bits in a syndrome calculation during Reed-Solomon decoding of TMCC information, a site diversity switching detection signal and a main station / A site diversity switching detection circuit 11 for outputting a sub station status signal is provided.
[0023]
Here, means for detecting that an error bit is equal to or less than a predetermined number of bits in a syndrome calculation during Reed-Solomon decoding of TMCC information corresponds to TMCC status signal generation means.
[0024]
Therefore, during normal operation, the TMCC status signal is output because the number of error bits is not more than a predetermined number in the syndrome calculation during Reed-Solomon decoding of TMCC information. When the error bit exceeds a predetermined number of bits in the syndrome calculation during Reed-Solomon decoding of TMCC information after site switching or the like, the TMCC status signal is detected as being interrupted.
[0025]
Next, generation of the reception status signal will be described with reference to FIG.
[0026]
As shown in FIG. 3, in the 8PSK / QPSK / BPSK demodulation circuit 23, the reproduction carriers orthogonal to the baseband signals I and Q (reproduction output from the carrier reproduction circuit 23-0) output from the numerically controlled oscillator 23-7. The carrier) is multiplied by the arithmetic circuit 23-1, and the baseband signals I and Q are quadrature-detected. The quadrature-detected baseband signal is supplied to the roll-off filter 23-2 and band-limited.
[0027]
The baseband signal band-limited by the roll-off filter 23-2 is supplied to the frame synchronization detection circuit 23-3 and the carrier recovery phase error table 23-4. The main signal identification signal generated from the TMCC information is sent to the carrier reproduction phase error table 21.
[0028]
In the carrier reproduction phase error table 23-4 that has received the main signal identification signal, the phase error table based on the modulation method of the main signal is selected, the phase of the band-limited baseband signal is detected, and the selected phase is selected. With reference to the error table, a phase error voltage based on the modulation method and the phase error is output from the carrier recovery phase error table 23-4.
[0029]
The phase error voltage is supplied to the AFC circuit 23-6 via the digital filter 23-5, and the phase error voltage is sequentially accumulated in the AFC circuit 23-6. The accumulated addition output at each addition point from the AFC circuit 23-6 is supplied to the numerically controlled oscillator 23-7, and positive and negative sine wave data and positive and negative cosine wave data based on the accumulated addition value are output. Here, it is similar to AFC in the sense that the oscillation frequency of the numerically controlled oscillator 23-7 is changed by the output at the time of cumulative addition, and is denoted as AFC circuit 23-6.
[0030]
In the arithmetic circuit 23-1, the positive sine wave data output from the numerically controlled oscillator 23-7 is multiplied by the baseband signal I, the negative cosine wave data is multiplied by the baseband signal Q, and this multiplication result is added. And output as a baseband signal Q from the arithmetic circuit 23-1. Similarly, the positive cosine wave data is multiplied by the baseband signal I, the negative sine wave data is multiplied by the baseband signal Q, and the multiplication result is added to the baseband signal I from the arithmetic circuit 23-1. Is output as In this way, quadrature detection is performed in the arithmetic circuit 23-1.
[0031]
On the other hand, the frame synchronization detection circuit 23-3 detects the frame synchronization pattern W1 from the supplied baseband signal. The retriggerable one-shot multivibrator 32-8 is triggered by the frame synchronization signal that has detected the frame synchronization pattern W1. The retriggerable one-shot multivibrator 32-8 generates an output for a period slightly longer than the cycle of the frame synchronization pattern W1 by the trigger. Therefore, when the frame synchronization pattern is continuously detected, a frame status signal is output.
[0032]
Here, the retriggerable one-shot multivibrator 23-8 that receives the output from the frame synchronization detection circuit 23-3 corresponds to the frame status signal generating means.
[0033]
When the detection of the frame synchronization pattern is interrupted, the retriggerable one-shot multivibrator 32-8 is not retriggered, and it is detected that the frame status signal is interrupted and the frame synchronization pattern is not continuously detected. Accordingly, when site switching is performed and frame synchronization patterns are not continuously detected, the frame status signal is detected by being interrupted.
[0034]
On the other hand, the phase error voltage based on the phase error output from the carrier reproduction phase error table 23-4 is also supplied to the comparison circuit 23-9, and is compared with a predetermined positive / negative threshold value. When it is within the positive and negative thresholds, the carrier reproduction status signal is output from the comparison circuit 23-9. When the phase error voltage exceeds the positive / negative threshold, the carrier reproduction status signal is not output from the comparison circuit 23-9. Therefore, when the site is switched and the phase comparison voltage exceeds the threshold value, the carrier reproduction status signal is detected by being interrupted.
[0035]
Here, the comparison circuit 23-9 that receives the output of the carrier reproduction phase error table 23-4 corresponds to the carrier reproduction stator signal generation means.
[0036]
Next, the site diversity switching detection circuit 11 will be described with reference to FIG.
[0037]
The site diversity switching detection circuit 11 receives the TMCC information decoded by the Reed-Solomon decoding circuit 26, and is reset by the superframe detection circuit 1 that detects a superframe from the TMCC information and the rising edge of the change instruction signal. A transmission switching signal detection circuit 4 that detects a transmission switching signal (bit 4 in the transmission / reception control information) from the TMCC information, and is enabled during a period in which the transmission switching signal detection circuit 4 detects the transmission switching signal. A super frame counter 2 that counts the number of super frames detected by the frame detection circuit 1, and a low potential output during the period when the super frame counter 2 receives the output of the super frame counter 2 and counts the 16th super frame. Site switching superframe detection times It is equipped with a 3 and.
[0038]
The site diversity switching detection circuit 11 further receives an input of the frame status signal, the carrier reproduction status signal, and the TMCC status signal, and detects that it cannot be detected by any one of the frame status signal, the carrier reproduction status signal, or the TMCC status signal. The frame status signal, the carrier reproduction status signal, or the TMCC during the period of counting the 16th super frame with the gate 5, the output of the AND gate 5 and the output of the site switching super frame detection circuit 3 as inputs. A NOR gate 6 that generates a high potential output when at least one of the status signals cannot be detected, a rising differentiation circuit 7 that differentiates the rising edge of the transmission switching signal detected by the transmission switching signal detection circuit 4, and a site switching switch -Set by the output of the OR gate 8 which receives the pulse output at the start of counting of the 16th superframe in the frame detection circuit 3 and the output of the rising differentiation circuit 7 and the output of the NOR gate 6, and by the output of the OR gate 8. An RS flip-flop 9 that resets and outputs an inverted Q output as a site diversity switching detection signal is provided.
[0039]
Here, the super frame detection circuit 1, the super frame counter 2, the site switching super frame detection circuit 3, and the transmission switching signal detection circuit 4 count the super frame from the start of the transmission switching signal output, and the predetermined number is set in the counting. The detection means corresponds to a detection means during the superframe counting period for detecting that it is during the superframe counting period.
[0040]
The AND gate 5, the NOR gate 6, the rising partial circuit 7, the OR gate 8, and the RS flip-flop 9 detect that at least one of the frame status signal, the carrier reproduction status signal, or the TMCC status signal is temporarily interrupted. This corresponds to detection means for transmitting a site diversity switching detection signal.
[0041]
The site diversity switching detection circuit 11 further includes a main / sub station detection circuit 10 for detecting a main station transmission signal / sub station transmission signal in TMCC information, and a main station / sub station status signal indicating an uplink station. Send it out.
[0042]
In the site diversity switching detection circuit 11 configured as described above, the change instruction signal and the transmission switching signal when the site switching is instructed are as shown in FIGS. 4 (a) and 4 (b). 5 (a), 5 (b), 6 (a), and 6 (b) are the reprints of FIG. 4 (a) and FIG. 4 (b).
[0043]
The super frame counter 2 detects a super frame from the TMCC information in the super frame detection circuit 1, detects a transmission switching signal from the TMCC information in the transmission switching signal detection circuit 4, and transmits a transmission switching instruction. Once enabled, the detected superframe is counted by the superframe counter 2. This state is as shown in FIG. FIG. 5C and FIG. 6C are a rewrite of FIG. 4C.
[0044]
On the other hand, the rising edge of the transmission switching signal detected by the transmission switching signal detection circuit 4 is differentiated by the rising differentiation circuit 7, and the differential output is sent through the OR gate 8 to the timing of the first reset pulse shown in FIG. The RS flip-flop 9 is reset, the inverted Q output of the RS flip-flop 9 becomes a high potential, and a high-potential site diversity switching detection signal is sent as shown in FIG. .
[0045]
On the other hand, the pulse when the counting of the 16th super frame in the super frame counter 2 is started, that is, the head pulse is shown in FIG. 4E from the site switching super frame detection circuit 3 via the OR gate 8. Output at the timing of the second reset pulse, the RS flip-flop 9 is reset, the inverted Q output of the RS flip-flop 9 is maintained at a high potential, and as shown in FIG. A potential site diversity switching detection signal is transmitted. Here, FIG. 5 (e) and FIG. 6 (e) are a rewrite of FIG. 4 (e).
[0046]
During the period when the 16th superframe is counted by the site switching superframe detection circuit 3, an output obtained by inverting the output from the site switching superframe detection circuit 3 is output to the NOR gate 6, and during this period, the frame status is displayed. When at least one of the signal, the carrier reproduction status signal, and the TMCC status signal is interrupted, the output from the AND gate 5 becomes a low potential and is output to the NOR gate 6. Therefore, the output of the NOR gate 6 generates a set pulse at the timing shown in FIG. 4D, the RS flip-flop 9 is set, and the inverted Q output of the RS flip-flop 9 becomes a low potential. From this time, a low-potential site diversity switching detection signal is sent out as shown in FIG.
[0047]
As a result, when at least one of the frame status signal, the carrier reproduction status signal, or the TMCC status signal is momentarily interrupted during the 16th counting period of the superframe during the period when the transmission switching signal is output, R- The digital satellite broadcast receiver side can detect that the inverted Q output of the S flip-flop 9 is at a low potential and the site switching has been normally performed.
[0048]
Here, before the period when the 16th superframe is counted by the site switching superframe detection circuit 3, at least one of the frame status signal, the carrier reproduction status signal, and the TMCC status signal is interrupted as shown in FIG. Then, the output from the AND gate 5 becomes a low potential before the site switching super frame detection circuit 3 counts the 16th super frame and is output to the NOR gate 6. Accordingly, the output of the NOR gate 6 is kept at a low potential as shown in FIG. 5D, the RS flip-flop 9 is not set, and the inverted Q output of the RS flip-flop 9 is maintained at a high potential. . As a result, as shown in FIG. 5F, a high-potential site diversity switching detection signal is transmitted.
[0049]
As a result, when at least one of the frame status signal, the carrier regeneration status signal, or the TMCC status signal is momentarily interrupted before the 16th counting period of the super frame in the period in which the transmission switching signal is output, Since the inverted Q output of the RS flip-flop 9 is maintained at a high potential, it can be detected on the digital satellite broadcast receiver side that the site switching has not been performed normally.
[0050]
If all of the frame status signal, the carrier reproduction status signal, and the TMCC status signal are not interrupted during the period until the 16th superframe count is finished by the site switching superframe detection circuit 3, During the period when the switching super frame detection circuit 3 counts the 16th super frame, the output from the AND gate 5 becomes a high potential and is output to the NOR gate 6. Accordingly, the output of the NOR gate 6 is kept at a low potential as shown in FIG. 6D, the RS flip-flop 9 is not set, and the inverted Q output of the RS flip-flop 9 is maintained at a high potential. . As a result, as shown in FIG. 6F, a high-potential site diversity switching detection signal is transmitted.
[0051]
As a result, during the period when the transmission switching signal is output, the frame status signal, the carrier reproduction status signal, and the TMCC status signal are momentarily interrupted during the period until the counting period of the 16th superframe of the superframe ends. If not, the inverted Q output of the RS flip-flop 9 is maintained at a high potential, and the digital satellite broadcast receiver can detect that site switching has not been performed normally.
[0052]
When the main station transmission signal in the TMCC information is detected by the main station / substation detection circuit 10, a signal indicating that the transmission is from the main station is transmitted, and the substation transmission signal in the TMCC information is When detected by the main station / sub station detection circuit 10, a signal indicating that the sub station is transmitting is transmitted.
[0053]
【The invention's effect】
As described above, according to the site diversity switching detection method and the satellite broadcast receiver with the site diversity switching detection function according to the present invention, when site diversity switching is performed, it is digitally determined whether or not switching has been normally performed with actual radio waves. It can be confirmed at the satellite broadcast receiver, and when there is a momentary interruption in the received image and sound, it can be distinguished whether or not the site switching has not been operated at the specified timing on the broadcast transmission side. The effect is obtained.
[0054]
Furthermore, according to the site diversity switching detection method and the satellite broadcast receiver with the site diversity switching detection function according to the present invention, when it is detected that the site switching has been correctly performed, in the subsequent stage of the digital satellite broadcast receiver. , Perform processing suitable for site diversity switching, and if it is determined that an incorrect switching has occurred, it is assumed that another failure has occurred and can be switched to processing suitable for that, and influence the received image and sound as much as possible. The effect that it can be reduced is obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a site diversity switching detection circuit to which a site diversity switching detection method according to an embodiment of the present invention is applied.
2 is a block diagram showing a schematic configuration of a digital satellite broadcast receiver including the site diversity switching detection circuit shown in FIG. 1. FIG.
3 is a block diagram showing a configuration of an 8PSK / QPSK / BPSK demodulation circuit shown in FIG. 2. FIG.
4 is a timing chart for explaining the operation of the site diversity switching detection circuit shown in FIG. 1; FIG.
FIG. 5 is a timing diagram for explaining the operation of the site diversity switching detection circuit shown in FIG. 1;
6 is a timing chart for explaining the operation of the site diversity switching detection circuit shown in FIG. 1; FIG.
FIG. 7 is an explanatory diagram of a frame configuration of a hierarchical transmission method.
FIG. 8 is an explanatory diagram of an extension area in TMCC information.
[Explanation of symbols]
1 Super frame detection circuit
2 Super frame counter
3 Site switching superframe detector
4 Transmission switching signal detection circuit
7 Rising differentiation circuit
9 RS flip-flop
11 Site diversity switching detection circuit
23 8PSK / QPSK / BPSK demodulation circuit
26 Reed-Solomon decoding circuit
23-0 Carrier regeneration circuit
23-3 Frame synchronization detection circuit
23-4 Phase error table for carrier reproduction
23-8 Retriggerable One-shot Multivibrator
23-9 Comparison circuit

Claims (4)

A site diversity switching detection method for detecting in a digital satellite broadcast receiver whether or not site switching has been operated at a specified timing on the broadcast transmission side, counting super frames from the start of transmission switching signal output, A frame status signal indicating that frame synchronization patterns are continuously detected, a carrier reproduction status signal indicating that carrier reproduction is normally performed, or TMCC during a predetermined superframe counting period in counting. A site diversity switching detection signal is transmitted when it is detected that at least one TMCC status signal indicating that the number of error bits in the information is equal to or less than a predetermined number is temporarily interrupted. Switching detection method. 2. The site diversity switching detection method according to claim 1, wherein the frame status signal is an output signal of a retriggerable one-shot multivibrator that is triggered every time a frame synchronization pattern is detected. . 2. The site diversity switching detection method according to claim 1, wherein the carrier reproduction status signal is a signal indicating that a phase error voltage for carrier reproduction is within a predetermined threshold value. Method. A digital satellite broadcast receiver that detects whether or not site switching has been operated at a specified timing on the broadcast transmission side, and counts superframes from the start of transmission switching signal output, Detecting means for detecting that a frame is being counted, detecting means for counting a super frame, a frame status signal generating means for generating a frame status signal indicating that a frame synchronization pattern is continuously detected, and carrier reproduction Carrier reproduction status signal generating means for generating a carrier reproduction status signal indicating that the error is normally performed, and TMCC for generating a TMCC status signal indicating that the error bits in the TMCC information are equal to or less than a predetermined number Status signal generation means, frame status signal, carry Satellite broadcast reception with a site diversity switching detection function, characterized by comprising detection means for detecting that at least one of the reproduction status signal or TMCC status signal is temporarily interrupted and transmitting a site diversity switching detection signal Machine.

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