JP2002064415A - Method for detecting site diversity switching and satellite broadcasting receiver with site diversity switching detecting function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for detecting site diversity switching by which whether or not site switching is operated at specified timing on a broadcast transmitting side by using a digital satellite broadcasting receiver and to provide a satellite broadcasting receiver having a site diversity switching detecting function. SOLUTION: The number of superframes is counted from the output starting time of a transmission switching signal and, when it is detected that at least one of a frame status signal indicating that a frame synchronizing pattern is continuously detected, a carrier reproduction status signal indicating that carrier reproduction is normally performed, or a TMCC status signal indicating that the number of error bits in TMCC information is smaller than a predetermined number ceases during the counting period of the sixteenth super-frame in the course of counting the number of super-frames, a site diversity switching detecting signal is outputted. Therefore, whether or not site switching is operated at the specified timing on the broadcast transmitting side can be detected from the site diversity switching detecting signal on the digital satellite broadcasting receiver side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a site diversity switching detection method and a satellite having a site diversity switching detection function which can be used in a digital satellite broadcast receiver and can confirm on the receiving side that site diversity switching has been performed. It relates to a broadcast receiver.

[0002]

2. Description of the Related Art In digital satellite broadcasting, "ARIB"
"STD-B20" BS digital broadcast transmission / operation conditions, "ARIB STD-B21" BS digital broadcast receiver, "ARIB TR-B15" BS digital operation regulations, 7th BS digital broadcast transmission operation regulations are defined. According to this, when it is expected that it is impossible to secure a line around one of the operating uplink broadcast stations due to rainfall or the like, site diversity that switches to operation by another uplink broadcast station is adopted. In this site diversity, it is desirable to minimize the influence of switching between uplink broadcasting stations, such as interruption of video and audio, as much as possible.

In this specification, switching from one operating uplink broadcasting station to operating by the other uplink broadcasting station is also referred to as site switching.

[0004] However, when the sites are switched, the continuity of the signals input to the digital satellite broadcast receiver cannot be maintained even if the timing of the transmission signals is adjusted in both uplink broadcasting stations. For this reason, an instantaneous interruption will occur in the video and audio decoded by the digital satellite broadcast receiver.

[0005] In order to reduce the instantaneous interruption as much as possible, the occurrence of the instantaneous interruption of the carrier may be transmitted to a digital satellite broadcast receiver in advance. For this reason, in the site diversity between the main station (one uplink broadcasting station) and the substation (the other uplink broadcasting station) performed in the broadcasting device of the uplink broadcasting station, the switching instruction for the switching instruction is included in the TMCC information. The bit is set, and the site is switched within the period of the Nth super frame immediately after the bit is set.

[0006]

However, when the site diversity switching is performed, there is no method for confirming whether the switching has been normally performed by the actual radio wave in the digital satellite broadcast receiver. For this reason, even if a momentary interruption occurs in the received image and the sound, the broadcast sending side cannot distinguish whether or not the site switching was not operated at the prescribed timing.

[0007] The present invention provides a site diversity switch detection method and a satellite broadcast with a site diversity switch detection function which can detect whether or not a site switch has been performed at a specified timing on the broadcast sending side with a digital satellite broadcast receiver. It is intended to provide a receiver.

[0008]

SUMMARY OF THE INVENTION A site diversity switching detection method according to the present invention comprises the step of detecting in a digital satellite broadcast receiver whether or not switching of a site has been performed at a specified timing on a broadcast transmitting side. A method for counting superframes from the start of output of a transmission switching signal, and a frame status signal indicating that a frame synchronization pattern is continuously detected during a counting period of a predetermined superframe in the counting. That at least one of a carrier reproduction status signal indicating that carrier reproduction is normally performed, or a TMCC status signal indicating that the number of error bits in the TMCC information is equal to or less than a predetermined number is temporarily stopped. Sends a site diversity switch detection signal when It is characterized in.

A satellite broadcast receiver with a site diversity switch detection function according to the present invention is a digital satellite broadcast receiver for detecting whether or not a site switch has been performed at a specified timing on a broadcast sending side. A superframe is counted from the start of signal output, and a superframe counting period detecting means for detecting that a superframe counting period is predetermined during the counting, and a frame synchronization pattern are continuously detected. Frame status signal generating means for generating a frame status signal indicating that the carrier is reproduced, carrier recovery status signal generating means for generating a carrier reproduction status signal indicating that carrier reproduction is normally performed, and an error bit in the TMCC information. Is less than or equal to a predetermined number.
TMCC status signal generating means for generating an MCC status signal, and detecting means for detecting that at least one of a frame status signal, a carrier reproduction status signal, or a TMCC status signal is temporarily interrupted and transmitting a site diversity switching detection signal And characterized in that:

[0010] According to the site diversity switch detection method and the satellite broadcast receiver with the site diversity switch detection function of the present invention, superframes are counted from the start of transmission switch signal output, and superframes determined in advance in the counting are determined. During the counting period, a frame status signal indicating that a frame synchronization pattern is continuously detected, a carrier reproduction status signal indicating that carrier reproduction is normally performed, or an error bit in TMCC information is predetermined. When it is detected that at least one of the TMCC status signals indicating that the number is equal to or less than the predetermined number 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 has been operated at the specified timing on the broadcast sending side by the site diversity switching detection signal. As a result, if it is detected that the site switching has been correctly performed, a process suitable for the site diversity switching is performed in the subsequent stage of the digital satellite broadcast receiver, and when it is determined that the incorrect switching has occurred, other troubles are caused. By assuming that this has occurred, and by switching to processing suitable for it, it is possible to minimize the effect on the received image and sound.

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 triggered each time a frame synchronization pattern is detected, and the carrier reproduction status signal May be a signal indicating that the phase error voltage for carrier regeneration is within a predetermined threshold.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A site diversity switching detection method according to the present invention will be described below with reference to an embodiment.

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, and FIG. 2 is a site diversity switching detection circuit shown in FIG. FIG. 2 is a block diagram illustrating a schematic configuration of a digital satellite broadcast receiver including the above.

Before describing the site diversity switching detection circuit in FIG. 1, a frame configuration of a hierarchical transmission system used in digital satellite broadcasting will be described.

As is well known, one superframe corresponds to FIG.
As shown in FIG. 7A, each frame is composed of eight frames. As shown in FIG. 7B, each frame includes a frame synchronization pattern W1, a transmission parameter, a modulation scheme, and a TMCC (TMCC) for identifying a transmission multiplex configuration such as control information. Transmission and M
ultiplexing configuration control) information, a frame identification synchronization pattern W2 or W3 for identifying whether or not the frame is the first frame in a superframe, a main signal, a reference burst signal, a main signal, a reference burst signal, ..., a main signal, a reference burst. It consists of signals. The frame identification synchronization pattern W2 is used for the first frame in the superframe, and the frame identification synchronization pattern W3 is used for the second to eighth frames. In FIG. 7B, the second
The second frame is shown.

The modulation method of the main signal is trellis code 8PS.
K, QPSK or BPSK, the frame synchronization pattern W1, the frame identification synchronization patterns W2, W3, T
The modulation scheme of the MCC information and the reference burst signal is BPS
K, the frame synchronization pattern W1, the frame identification synchronization patterns W2 and W3 are each 32 symbols (including 20 fixed bit symbols), the TMCC information is 128 symbols, the main signal is 203 symbols, and the reference burst signal is 4 symbols. is there. One frame is composed of 39936 symbols.

The extension area in the TMCC information includes 5 bits for a change instruction and 5 bits for transmission / reception control information as shown in FIG. The change instruction 5 bit is set to 1 every time the contents of TMCC information such as a site diversity instruction change.
Is incremented by one. In the case of 5-bit transmission / reception control information, FIG.
As shown in (b), bit 4 indicates a transmission / reception switching signal, bit 3 is a main station transmission signal, and bit 2 is a sub station transmission signal.

FIG. 8 (c-1) shows bit 4 in the transmission / reception control information, and FIG. 8 (c-2) shows 5 bits of a change instruction instruction. At the time of site switching, the change instruction instruction 5 bits are incremented by 1 and a bit is set in bit 4 of the transmission / reception control information (bit 4 = 1), and when the bit is set, that is, when a transmission switching signal is received, Switching of sites is performed during the superframe when the superframe (SF) is counted N times, and after performing site diversity, the bit of bit 4 in the transmission / reception control information is lowered in the M superframe (bit 4 = 0). To be. At present, N = 16 and M in FIG.
= 0.

By setting a bit at bit 3 in the transmission / reception control information, the master station instructs an uplink, and by setting a bit at bit 2 in the transmission / reception control information, a sub-station instructs an uplink. are doing.

Next, description will be made returning to FIG. The received signal in the digital satellite broadcast receiver is supplied to a front-end tuner 21, where it is tuned to a desired broadcast based on the reception channel selection, converted into an intermediate frequency signal having an intermediate frequency that is easy to process, and the baseband signals I, Q Is demodulated. Demodulated baseband signals I and Q output from the front end tuner 21 are supplied to an A / D converter 22 where they are A / D converted, and the A / D converted output is 8PSK / Q.
The signal is supplied to the PSK / BPSK demodulation circuit 23 and PSK demodulation is performed.

8PSK / QPSK / BPSK demodulation circuit 2
3, the trellis / Viterbi decoding circuit 24 performs trellis / Viterbi decoding on the baseband signals I and Q before error correction, which are PSK-demodulated by DSK 3, and deinterleaves the data subjected to the trellis / Viterbi decoding and the deinterleave circuit 25 , Are descrambled, and are subjected to Reed-Solomon decoding in the Reed-Solomon decoding circuit 26 and output.

In a digital satellite broadcast receiver, 8PS
A reception status signal including a frame status signal indicating that a frame synchronization signal is normally detected in the K / QPSK / BPSK demodulation circuit 23, a carrier reproduction status signal indicating that carrier reproduction is normally performed, and TMCC. In a syndrome operation during Reed-Solomon decoding of information, a TMCC status signal indicating that the number of error bits is equal to or less than a predetermined number of bits and TMCC information are input, and a site diversity switching detection signal and a master / substation status signal are output. And a site diversity switching detection circuit 11 to be used.

Here, means for detecting that the number of error bits is equal to or less than a predetermined number of bits in a syndrome operation during Reed-Solomon decoding of TMCC information is TMCC information.
It corresponds to the status signal generating means.

Therefore, during normal operation, T
In the syndrome operation during Reed-Solomon decoding of the MCC information, the number of error bits is equal to or less than a predetermined number of bits, and a TMCC status signal is output. If the number of error bits exceeds a predetermined number in the syndrome calculation during Reed-Solomon decoding of TMCC information due to switching of sites or the like, it is detected by the interruption of the TMCC status signal.

Next, generation of the reception status signal will be described with reference to FIG.

As shown in FIG. 3, 8PSK / QPSK /
In the BPSK demodulation circuit 23, the baseband signals I and Q are multiplied by orthogonal reproduction carriers (reproduction carriers output from the carrier reproduction circuit 23-0) output from the numerical control oscillator 23-7 in the arithmetic circuit 23-1. Thus, the baseband signals I and Q are subjected to quadrature detection. The baseband signal subjected to the quadrature detection is supplied to a roll-off filter 23-2 and band-limited.

The baseband signal band-limited by the roll-off filter 23-2 is transmitted to the frame synchronization detection circuit 23-.
3 and the carrier reproduction 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.

In the carrier reproduction phase error table 23-4 receiving the main signal identification signal, a phase error table based on the modulation method of the main signal is selected, and the phase of the band-limited baseband signal is detected and selected. By referring to the obtained phase error table, the phase error voltage based on the modulation method and the phase error is converted into the carrier reproduction phase error table 23-4.
Output from

The phase error voltage is applied to the digital filter 23-5.
Is supplied to the AFC circuit 23-6, and the AFC circuit 23-6 sequentially accumulates and adds the phase error voltages.
The cumulative addition output at each addition time from the AFC circuit 23-6 is supplied to the numerical control oscillator 23-7, and positive and negative sine wave data and positive and negative cosine wave data of a frequency based on the cumulative addition value are output. Here, the AFC circuit 23-6 is similar to the AFC in that the oscillation frequency of the numerically controlled oscillator 23-7 is changed by the output at the time of the cumulative addition.
It is written.

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, and the negative cosine wave data is multiplied by the baseband signal Q. The results are added and output as a baseband signal Q from the arithmetic circuit 23-1.
Similarly, the positive cosine wave data is the baseband signal I
, The negative sine wave data is multiplied by the baseband signal Q, and the result of the multiplication is added to the arithmetic circuit 23-1.
Is output as a baseband signal I. Thus, the quadrature detection is performed in the arithmetic circuit 23-1.

On the other hand, the frame synchronization detection circuit 23-3 detects a 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. When triggered, the retriggerable one-shot multivibrator 32-8 generates an output for a period slightly longer than the period of the frame synchronization pattern W1. Therefore, when a frame synchronization pattern is continuously detected, a frame status signal is output.

Here, the retriggerable one-shot multivibrator 23-8 receiving the output from the frame synchronization detecting circuit 23-3 corresponds to a frame status signal generating means.

When the detection of the frame synchronization pattern is interrupted, the retriggerable one-shot multivibrator 3
2-8 are not retriggered, and it is detected that the frame status signal is interrupted and the frame synchronization pattern is not continuously detected. Therefore, when the switching of the sites is not performed and the continuous detection of the frame synchronization pattern is not performed, it is detected by the interruption of the frame status signal.

On the other hand, the carrier reproduction phase error table 2
The phase error voltage based on the phase error output from 3-4 is also supplied to a comparison circuit 23-9, where it is compared with a predetermined positive / negative threshold. When the phase error voltage is within the positive / negative threshold, the comparison is performed. The circuit 23-9 outputs a carrier reproduction status signal. When the phase error voltage exceeds the positive / negative threshold, the comparison circuit 23-9 does not output the carrier reproduction status signal. Therefore, when the site switching is performed and the phase comparison voltage exceeds the threshold value, it is detected by the interruption of the carrier reproduction status signal.

Here, the comparison circuit 23-9 receiving the output of the carrier reproduction phase error table 23-4 corresponds to a carrier reproduction stator signal generating means.

Next, the site diversity switching detection circuit 11 will be described with reference to FIG.

Site diversity switching detection circuit 11
Is the TMC decoded by the Reed-Solomon decoding circuit 26.
A superframe detection circuit 1 that detects a superframe from TMCC information upon receiving the C information, and detects a transmission switching signal (bit 4 in transmission / reception control information) from TMCC information, reset by the rise of a change instruction signal. A transmission switching signal detection circuit 4 and a super frame counter 2 which is enabled during the period when the transmission switching signal detection circuit 4 is detecting the transmission switching signal and counts the number of super frames detected by the super frame detection circuit 1. And a site switching superframe detecting circuit 3 which receives the output of the superframe counter 2 and generates a low potential output during the period when the superframe counter 2 is counting the 16th superframe.

Site diversity switching detection circuit 11
Further receives an input of a frame status signal, a carrier reproduction status signal, and a TMCC status signal, and detects that even one of the frame status signal, the carrier reproduction status signal, or the TMCC status signal cannot be detected, and an AND gate 5; 5 and the output of the site switching superframe detection circuit 3, at least one of the frame status signal, the carrier reproduction status signal, or the TMCC status signal is generated during the period of counting the 16th superframe. The NOR gate 6 that generates a high potential output when the signal cannot be detected, the rising differentiating circuit 7 that differentiates the rising of the transmission switching signal detected by the transmission switching signal detection circuit 4, and the sixteenth An OR gate 8 which receives the pulse output at the start of the counting of the superframe of the eye and the output of the rising differentiating circuit 7 as an input, is set by the output of the NOR gate 6, and is reset by the output of the OR gate 8, and the inverted Q output RS flip-flop 9 for sending out as a site diversity switching detection signal
And

The superframe detection circuit 1, superframe counter 2, site switching superframe detection circuit 3, and transmission switching signal detection circuit 4 count superframes from the start of transmission switching signal output. It corresponds to a superframe counting period detecting means for detecting that a predetermined superframe counting period is being performed.

The AND gate 5, the NOR gate 6, the rising sub-circuit 7, the OR gate 8, and the RS flip-flop 9 indicate that at least one of the frame status signal, the carrier reproduction status signal, and the TMCC status signal has been temporarily stopped. It corresponds to a detecting means for detecting and transmitting a site diversity switching detection signal.

Site diversity switching detection circuit 11
Further comprises a main / substation detection circuit 10 for detecting a main / substation transmission signal in the TMCC information, and transmits a main / substation status signal indicating an uplink station.

In the site diversity switching detection circuit 11 configured as described above, a change instruction signal and a transmission switching signal when a site switching is instructed are as shown in FIGS. 4 (a) and 4 (b). is there. 5 (a) and 5 (b), FIG. 6 (a) and FIG.
(B) is a rewrite of FIGS. 4 (a) and 4 (b).

A super frame is detected in the super frame detecting circuit 1 from the TMCC information,
While the transmission switching signal is detected from the information by the transmission switching signal detection circuit 4 and the transmission switching instruction is given, the super frame counter 2 is enabled, and the detected super frames are counted by the super frame counter 2. You. This state is as shown in FIG. FIG. 5C and FIG. 6C rewrite FIG. 4C.

On the other hand, the rise of the transmission switching signal detected by the transmission switching signal detection circuit 4 is differentiated by the rising differentiation circuit 7, and the differentiated output is output via the OR gate 8 to the first reset shown in FIG. The pulse is output at the timing, 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 as shown in FIG. Sent out.

On the other hand, the pulse at the time when the counting of the 16th superframe in the superframe counter 2 is started, that is, the leading pulse, is supplied from the site switching superframe detection circuit 3 via the OR gate 8 to FIG. Is output at the timing of the second reset pulse shown in FIG. 4, the RS flip-flop 9 is reset, the inverted Q output of the RS flip-flop 9 is maintained at a high potential, and shown in FIG. Thus, a high potential site diversity switching detection signal is transmitted. Here, FIG. 5E and FIG. 6E rewrite FIG. 4E.

During the period in which the 16th superframe is counted by the site switching superframe detection circuit 3, an inverted output of the output from the site switching superframe detection circuit 3 is output to the NOR gate 6, and during this period, When at least one of the frame status signal, the carrier reproduction status signal, and the TMCC status signal is interrupted, the output from the AND gate 5 becomes 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 low potential, From this time, a low potential site diversity switching detection signal is transmitted as shown in FIG.

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 super frame during the period in which the transmission switching signal is output, , And the inverted Q output of the RS flip-flop 9 becomes low potential, and the digital satellite broadcast receiver can detect that the site switching is normally performed.

Here, before the period in which the 16th superframe is counted by the site switching superframe detection circuit 3, as shown in FIG. 5, the frame status signal, the carrier reproduction status signal,
When at least one of the C status signals is interrupted, the output from the AND gate 5 becomes low potential before the period when the 16th superframe is counted by the site switching superframe detection circuit 3 and is output to the NOR gate 6. . Therefore, the output of NOR gate 6 is shown in FIG.
As shown in (d), the low potential is maintained, the RS flip-flop 9 is not set, and the RS flip-flop 9
Is maintained at a high potential. As a result, FIG.
As shown in (f), a high potential site diversity switching detection signal is transmitted.

As a result, during the period in which the transmission switching signal is output, at least one of the frame status signal, the carrier reproduction status signal, or the TMCC status signal is momentarily interrupted before the 16th counting period of the superframe. In the case, the RS flip-flop 9
Is maintained at a high potential, and the digital satellite broadcast receiver can detect that the site switching was not performed normally.

In the case where all of the frame status signal, the carrier reproduction status signal and the TMCC status signal are not interrupted until the counting of the 16th superframe is completed by the site switching superframe detection circuit 3. During the period in which the 16th superframe is counted by the site switching superframe detection circuit 3, the output from the AND gate 5 becomes high potential and is output to the NOR gate 6. Therefore, the output of the NOR gate 6 is shown in FIG.
As shown in (1), the low potential is continued, the RS flip-flop 9 is not set, and the inverted Q output of the RS flip-flop 9 is maintained at the high potential. As a result, as shown in FIG. 6F, a high potential site diversity switching detection signal is transmitted.

As a result, while the transmission switching signal is being output, the frame status signal, the carrier reproduction status signal, and the TMCC status signal are output until the 16th superframe counting period of the superframe ends. If there is no instantaneous interruption, 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 the site switching was not performed normally. it can.

When the main station transmission signal in the TMCC information is detected by the main / sub station detection circuit 10, a signal indicating that the signal is transmitted from the main station is transmitted, and the sub station in the TMCC information is transmitted. When the transmission signal is detected by the main / substation detection circuit 10, a signal indicating that the transmission is from the substation is transmitted.

[0053]

As described above, according to the site diversity switching detection method and the satellite broadcasting receiver with the site diversity switching detection function of the present invention, when the site diversity switching is performed, the switching is performed normally with the actual radio wave. Can be confirmed by the digital satellite broadcast receiver, and when a momentary interruption occurs in the received image and sound, whether or not the site switching was not operated at the specified timing on the broadcast sending side The effect of being able to distinguish is obtained.

Further, according to the site diversity switching detection method and the satellite broadcasting receiver with the site diversity switching detecting function of the present invention, when it is detected that the site switching has been performed correctly, the digital satellite broadcasting receiver In the latter stage, processing suitable for site diversity switching is performed, and when it is determined that an incorrect switching has occurred, it is assumed that another failure has occurred, and that processing can be switched to processing suitable for that, and processing for received images and audio can be performed. The effect is obtained that the influence can be minimized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating 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.

FIG. 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.

FIG. 3 is a block diagram showing a configuration of an 8PSK / QPSK / BPSK demodulation circuit shown in FIG.

FIG. 4 is a timing chart for explaining the operation of the site diversity switching detection circuit shown in FIG. 1;

FIG. 5 is a timing chart for explaining the operation of the site diversity switching detection circuit shown in FIG. 1;

FIG. 6 is a timing chart for explaining the operation of the site diversity switching detection circuit shown in FIG. 1;

FIG. 7 is an explanatory diagram of a frame configuration of a hierarchical transmission scheme.

FIG. 8 is an explanatory diagram of an extension area in TMCC information.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 superframe detection circuit 2 superframe 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 recovery circuit 23-3 Frame synchronization detection circuit 23-4 Carrier recovery phase error table 23-8 Retriggerable one-shot multivibrator 23-9 Comparison circuit

Continued on the front page (72) Inventor Kenichi Ishihara 1-1-16-2 Hakusan, Midori-ku, Yokohama-shi Kenwood Tea M.I. Co., Ltd. (72) Inventor Akihiro Horii 1-14-6 Dogenzaka, Shibuya-ku, Tokyo Stock (72) Inventor Hisakazu Kato 2-2-1 Jinnan, Shibuya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Center (72) Inventor Yuji Okawa 2-1-1 Jinnan, Shibuya-ku, Tokyo Japan Inside the Association Broadcasting Center (72) Inventor Akira Hanada 2-2-1 Jinnan, Shibuya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Center F-term (reference) 5C025 AA25 AA30 BA25 BA30 DA01 DA05 DA10 5K059 AA08 BB08 CC02 DD01 EE02

Claims (4)

[Claims] 1. A site diversity switching detection method for detecting, in a digital satellite broadcast receiver, whether or not site switching has been performed at a prescribed timing on a broadcast transmitting side, comprising: And a frame status signal indicating that a frame synchronization pattern is continuously detected during a counting period of a superframe predetermined in the counting, and a carrier reproduction indicating that carrier reproduction is normally performed. When detecting that at least one of the status signal or the TMCC status signal indicating that the number of error bits in the TMCC information is equal to or less than a predetermined number is temporarily stopped, transmitting a site diversity switching detection signal. Characteristic site diversity switching detection method. 2. A site diversity switching detection method according to claim 1, wherein the frame status signal is an output signal of a retriggerable one-shot multivibrator triggered every time a frame synchronization pattern is detected. Site diversity switching detection method. 3. The site diversity switching detection method according to claim 1, wherein the carrier regeneration status signal is a signal indicating that a phase error voltage for carrier regeneration is within a predetermined threshold. Site diversity switching detection method. 4. A digital satellite broadcast receiver for detecting whether or not site switching has been performed at a prescribed timing on a broadcast transmitting side, wherein the digital satellite broadcasting receiver counts superframes from the start of transmission switch signal output, and And a frame status signal generating means for generating a frame status signal indicating that a frame synchronization pattern is continuously detected, and a super frame counting period detecting means for detecting that a predetermined super frame counting period is being performed. Means,
Carrier reproduction status signal generating means for generating a carrier reproduction status signal indicating that carrier reproduction is normally performed, and generating a TMCC status signal indicating that the number of error bits in the TMCC information is equal to or less than a predetermined number. A TMCC status signal generating means, a frame status signal, a carrier reproduction status signal,
Or a detecting means for detecting that at least one of the TMCC status signals is temporarily interrupted and transmitting a site diversity switching detection signal, wherein the satellite broadcasting receiver has a site diversity switching detecting function.