JP4268555B2 - Transmission control signal receiver and digital terrestrial television broadcast receiver using the same - Google Patents

Description

  The present invention relates to a transmission control signal receiver and a terrestrial digital television broadcast receiver using the transmission control signal receiver, and a transmission control signal receiver for receiving a transmission control signal of terrestrial digital television broadcast and a terrestrial digital television broadcast using the same. Regarding the receiver.

  FIG. 1 shows a block diagram of an example of an analog television broadcast receiver that receives a conventional emergency alert broadcast. An antenna reception signal output from the reception antenna 1 is input to the analog television broadcast tuner 2. The video signal and audio signal output from the analog television broadcast tuner 2 are input to the receiver 3. The analog television broadcast tuner 2 is fed from a power source 4 through a feeder line 5.

  In order to receive the emergency alert broadcast, the demodulation system of the analog television broadcast tuner 2 needs to be in an operating state. On the other hand, the receiver 3 is supplied with power from the power source 4 through the power supply line 6 and through the switch 7. In the standby state, the power source of the receiver 3 is turned off by the switch 7.

  When the analog television broadcast tuner 2 receives the emergency warning broadcast start flag, the switch-on signal 8 is output from the analog television broadcast tuner 2 to the switch 7, the switch 7 is turned on, and the receiver 3 is supplied with power and operates. It becomes.

As an emergency alert broadcast receiving system that receives an emergency alert broadcast that is broadcast superimposed on a BS television broadcast, for example, there is a system described in Patent Document 1.
JP 2004-23591 A

  As with analog television broadcasting, in order to activate a receiver by emergency warning broadcasting in terrestrial digital television broadcasting, the demodulation system of the digital terrestrial television broadcasting receiver can receive the emergency warning broadcasting activation flag of the transmission control signal. Must be kept in a powered state.

  FIG. 2 is a block diagram showing an example of a demodulation system of the terrestrial digital television broadcast receiver. The antenna reception signal received by the reception antenna is supplied to the channel selection unit 10 and the signal of the designated channel is selected. This signal is digitized, and then orthogonally demodulated by the orthogonal demodulation unit 11 and supplied to the synchronous reproduction unit 12 and the FFT unit 13.

  The synchronous reproduction unit 12 reproduces the OFDM symbol synchronization and the FFT sample frequency according to the mode and the guard interval length. The FFT unit 13 performs an FFT (Fast Fourier Transform) operation for the effective symbol period of the OFDM symbol. The frame extraction unit 14 extracts a frame synchronization signal from a TMCC (Transmission and Multiplexing Configuration Control: transmission control signal) signal output from the FFT unit 13. The TMCC decoding unit 15 extracts various control information including an emergency warning broadcast activation flag from the TMCC signal.

  The carrier demodulation unit 16 performs carrier demodulation according to the TMCC information and detects amplitude and phase information. The demapping section 17 performs QPSK, 16QAM and 64QAM demapping from the carrier demodulated information to extract bit information. The TS playback unit 18 performs processing for transport stream playback. The RS decoding unit 19 decodes the shortened Reed-Solomon code, and decodes baseband MPEG-TS (Transport Stream).

  In order to keep the demodulation system of the terrestrial digital television broadcast receiver in an energized state, power consumption of at least several hundred mW or more is necessary. In portable receivers that operate on batteries due to battery capacity restrictions, There is a problem that activation of a receiver by emergency alert broadcasting is not practical and difficult to implement.

  The present invention has been made in view of the above points, and provides a transmission control signal receiver capable of reducing standby power for receiving a transmission control signal and a terrestrial digital television broadcast receiver using the same. For the purpose.

The invention described in claim 1 generates a reference frequency signal synchronized with the frequency of the pilot carriers in the band upper end of the reception channel signal of the terrestrial digital television broadcasting, generated from the received channel signal and the reference frequency signal transmission mixing the signal of the control signal frequency to obtain a transmission control signal carrier, it extracts the transmission control signal component is a low-frequency component of the pre-Symbol transmission control signal carrier, and the transmission control signal component, based on the reference frequency signal a transmission control signal receiver for obtaining the transmitted control signal from the correlation of the synchronization signal pattern of the generated said transmission control signal Te,
Based on the reference frequency signal synchronized with the frequency of the pilot carrier at the upper end of the band of the reception channel signal of the terrestrial digital television broadcast, the transmission control signal of the same frequency as the transmission control signal included in the reception channel signal of the terrestrial digital television broadcast Detecting means for generating a frequency signal and mixing the reception channel signal and the frequency signal to obtain a transmission control signal carrier;
Synchronous reproduction means for reproducing symbol synchronization from the transmission control signal carrier to obtain a symbol synchronization signal, switching based on the symbol synchronization signal, integrating the transmission control signal carrier with a capacitor, The transmission control signal component, which is a low frequency component, has a normalized frequency characteristic.
sinc (πf) = sin (πf) / πf
Transmission control signal component extracting means having filter means for extracting with a low-pass filter,
A dedicated receiver for transmission control signals,
Majority determination means for determining the majority of transmission control signals obtained by four systems of dedicated receivers for transmission control signals;
Correlation receiving means for correlating and receiving the transmission control signal determined by majority decision by the majority decision determining means with the synchronization signal pattern of the transmission control signal;
With
The correlation receiving means performs correlation reception of the transmission control signal determined by majority decision with a differential demodulation reference 1 bit of a known transmission control signal, a synchronization signal of 16 bits, and a segment format identification of 3 bits, and a correlation is obtained. Only in this case, the emergency warning broadcast activation flag in the transmission control signal determined by majority decision is output.

The invention described in claim 2 is a digital terrestrial television broadcast receiver having the transmission control signal receiver described in claim 1 ,
The transmission control signal receiver when detecting an emergency alert broadcast activation flag in the transmission control signal, to supply power to the tuner of the digital terrestrial television receiver on the basis of the detection result.

  According to the present invention, standby power for receiving a transmission control signal can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 3 shows a block diagram of an embodiment of a digital terrestrial television broadcast receiver to which the transmission control signal receiver of the present invention is applied. In FIG. 3, the antenna reception signal from the reception antenna 20 is distributed by a distributor 22, one is supplied to a TMCC dedicated receiver 24 as a transmission control signal receiver, and the other is a terrestrial digital television broadcast tuner. 26.

  The video signal and audio signal output from the terrestrial digital television broadcast tuner 26 are input to the receiver 28. The terrestrial digital television broadcast tuner 26 is supplied with power from a power source 30 through a power supply line 32 and a switch 36. The receiver 28 is supplied with power from a power source 30 through a power supply line 40 and a switch 42. In the standby state, the power supply of the digital terrestrial television broadcast tuner 26 is turned off by the switch 36 and the power supply of the receiver 28 is turned off by the switch 42.

  The TMCC dedicated receiver 24 as a transmission control signal receiver is supplied with power from the power supply 30 through the power supply line 38 and is always in an operating state. The TMCC dedicated receiver 24 outputs a switch-on signal 46 when receiving the emergency warning broadcast activation flag included in the TMCC signal of the terrestrial digital television broadcast wave, and switches the switch 36 connected from the power supply 30 via the feeder line 32. The terrestrial digital television broadcast tuner 26 is activated by turning on the power. The terrestrial digital television broadcast tuner 26 is in a state where it can receive an emergency warning broadcast for the first time. When the terrestrial digital television broadcast tuner 26 receives the emergency warning broadcast activation flag, a switch-on signal 44 is output from the terrestrial digital television broadcast tuner 26 to the switch 42, the switch 42 is turned on, and the receiver 28 is supplied from the power source 30. Power is supplied and it becomes an operating state. Note that the switch 42 may be closed (turned on) together with the switch 36 by the switch-on signal 46.

  FIG. 4 shows a block diagram of a first embodiment of the transmission control signal receiver of the present invention. Here, the transmission mode of digital terrestrial television broadcasting will be described as mode 3. In FIG. 4, the distributed antenna reception signal is supplied to the selective amplifier 50 in the TMCC dedicated receiver 24 of the TMCC dedicated receiver 24 and amplified. The selective amplifier 50 selects a desired reception frequency range (reception channel C) under the control of a reception frequency setting circuit 64 described later, and selectively amplifies the vicinity of the desired reception frequency. The output signal of the selective amplifier 50 is distributed by the distributor 52 and supplied to the mixers 54 and 56.

  The voltage controlled oscillator 58 oscillates at a frequency fo (symbol frequency).

fo = 1000000/1008 [Hz] (1)
The reference frequency signal having the frequency fo is distributed by the distributor 60 and supplied to the m-multiplication PLL oscillator 62. The m-multiplication PLL oscillator 62 has its oscillation frequency and multiplication number controlled by the reception frequency setting circuit 64, and supplies a signal obtained by multiplying the frequency fo to m times to the mixer 54.

  Here, if the reception channel in UHF of digital terrestrial television broadcasting is C (C = 13 to 62), m is expressed by the equation (2), and the frequency fcp of the output signal of the m-multiplication PLL oscillator 316 is (3 ).

m = 6048 · C + 401112 (2)
fcp = m · fo (3)
The frequency fcp matches the frequency of the pilot carrier CP (Continuous Pilot) at the upper end of the band of the reception channel C. Therefore, a phase difference signal between the CP of the reception channel C included in the reception signal from the selective amplifier 50 and the output of the m-multiplication PLL oscillator 62 is obtained at the output of the mixer 54. This phase difference signal is fed back to the voltage controlled oscillator 58 with the low-pass filter 66 limiting the pass band to about several hundred Hz or less. As a result, the frequency of the voltage controlled oscillator 58 can be synchronized with the frequency of the CP of the reception channel C.

  A signal from the selective amplifier 50 distributed by the distributor 52 is input to the mixer 56. The output signal of the voltage controlled oscillator 58 is distributed by the distributor 60 and supplied to the n-multiplication PLL oscillator 68. The n-multiplication PLL oscillator 68 is controlled in oscillation frequency and multiplication number by the reception frequency setting circuit 64 and supplies a signal obtained by multiplying the frequency fo by n times to the mixer 56.

Here, using the reception channel C in UHF of digital terrestrial television broadcasting, n is represented by any one of the formulas (4.1), (4.2), (4.3), and (4.4). The frequency f _TMCC of the output signal of the n-multiplication PLL oscillator 68 is expressed by equation (5).

n = 6048 · C + 398189 (4.1)
n = 6048 · C + 398219 (4.2)
n = 6048 · C + 398374 (4 · 3)
n = 6048 · C + 398437 (4 · 4)
f _TMCC = n · fo (5)
The frequency f _TMCC matches one of the frequencies of TMCCl to TMCC4 in the segment 0 within the band of the reception channel C. Therefore, a phase difference signal between the TMCC signal included in the reception signal from the selective amplifier 50 and the output of the n-multiplication PLL oscillator 68 is obtained at the output of the mixer 56. In this phase difference signal, the TMCC signal is directly converted into a baseband signal, and the influence of OFDM (Orthogonal Frequency Division Multiplexing) other than the adjacent TMCC is included in the high frequency component. Therefore, a low-pass filter (LPF) 70 outputs a baseband TMCC signal in which the influence of adjacent carriers is eliminated by limiting the passband to about 1 kHz or less which is the carrier interval of the OFDM signal.

  The oscillation signal of the frequency fo output from the voltage controlled oscillator 58 is multiplied by the g / (g + 1) multiplier 72 and supplied to the TMCC differential pattern generation circuit 74 when the guard interval period is 1 / g of the effective symbol period. Supplied. The TMCC differential pattern generation circuit 74 is a differential pattern of 20 bits in total including a known TMCC differential demodulation reference 1 bit, a synchronization signal 16 bits and a segment format identification 3 bits synchronized with a signal of frequency fo · g / (g + 1). Is generated and supplied to the correlation receiving circuit 76.

  The baseband TMCC signal output from the low-pass filter 70 is correlated and received with the known 20-bit differential pattern in the correlation receiving circuit 76. When the TMCC can be normally received, the TMCC synchronization is established. The TMCC signal after the synchronization is established is supplied to an EWS (emergency warning broadcast activation flag) detection circuit 78, where the presence or absence of the 26th bit emergency warning broadcast activation flag of the TMCC signal is constantly monitored. When the EWS detection circuit 78 detects that the value of the emergency warning broadcast activation flag is “1: activation control is present”, it outputs a switch-on signal 46 to turn on a power switch such as the digital terrestrial television broadcast tuner 26. To.

  The terrestrial digital television broadcast tuner 26 includes an orthogonal demodulation unit 11, a synchronous reproduction unit 12, an FFT unit 13, a frame extraction unit 14, a TMCC decoding unit 15, a carrier demodulation unit 16, a demapping unit 17, and a TS reproduction unit illustrated in FIG. 18, in addition to the RS decoding unit 19, an audio processing unit, a video processing unit, and the like are included. For this reason, the power consumption of the terrestrial digital television broadcast tuner 26 is about several hundreds mW or more.

  On the other hand, since the TMCC dedicated receiver 24 demodulates only the TMCC carrier, the circuit scale is approximately the same as that of the synchronous reproduction unit 12 and the TMCC decoding unit 15 of the terrestrial digital television broadcast tuner 26, and the circuit configuration is simplified. The power consumption can be reduced to about several mW.

  As a result, by using the TMCC dedicated receiver 24 without putting the terrestrial digital television broadcast tuner 26 having a relatively large power consumption of about several hundred mW or more into a standby state, an emergency warning can be obtained with a low power consumption of about several mW. Broadcasting can be monitored constantly.

  In particular, an emergency warning broadcast service can be received anytime and anywhere for a terrestrial digital television broadcast receiver or a portable receiver built in a mobile phone or the like. In addition, the TMCC dedicated receiver 24 according to the present invention is incorporated in a remote controller of a general home terrestrial digital television broadcast receiver, or is incorporated in a remote controller dedicated to emergency alarm broadcasting, so that the terrestrial digital television broadcast receiver main body is incorporated. It will be possible to always respond to emergency alert broadcasting without remodeling.

  FIG. 5 shows a block diagram of a variation of the transmission control signal receiver of FIG. 4 of the present invention. 5, the TMCC dedicated receiver 34 is different from the TMCC dedicated receiver 24 of FIG. 4 in that the normalized frequency characteristic is sinc (πf) = sin (πf) / πf type instead of the low-pass filter 70. The low-pass filter 80 is used.

  The low pass filter 80 includes a distributor 82, a pulse generator 84, a switch 86, and a capacitor 88. The distributor 82 distributes the output signal of the g / (g + 1) multiplier 72 and supplies it to the pulse generator 84. The pulse generator 84 is supplied with a pulse timing control signal controlled from the correlation receiving circuit 76 so that the correlation is maximized.

  When the effective symbol period of the OFDM signal is Ta and the guard interval period is Tg, the pulse generator 84 is a switching signal having a period T (= Ta + Tg) that is high in the effective symbol period Ta and low in the guard interval period Tg. Is generated and supplied to the switch 86.

  The switch 86 is supplied with a phase difference signal from the mixer 56 to the terminal a, the terminal b is grounded, the terminal c is connected to the input terminal of the correlation receiving circuit 76 and the other end of the capacitor 88 grounded at one end. Yes. The switch 86 connects the terminals a and c when the switching signal supplied from the pulse generator 84 is high level, and connects the terminals b and c when the switching signal is low level. As a result, the effective symbol period Ta of the phase difference signal is integrated by the capacitor 88. This is equivalent to passing the phase difference signal through a low-pass filter whose frequency characteristic is sinc (πf / fa) = sin (πf / fa) / (πf / fa) with the frequency fa = 1 / Ta. .

  Therefore, only a baseband TMCC signal having a component of sin (πf / fa) / (πf / fa) and orthogonal to other carriers can be simply and ideally received without interference from other carriers. The baseband TMCC signal is supplied to the correlation receiving circuit 76.

  FIG. 6 shows a block diagram of a first embodiment of a terrestrial digital television broadcast receiver to which the TMCC dedicated receiver of FIG. 5 is applied. In the figure, the antenna reception signal from the reception antenna 90 is distributed by the distributor 92 and supplied to the frequency lock unit 94 and the TMCC synchronous detection unit 96 in the TMCC dedicated receiver 24 and the terrestrial digital television broadcast tuner 98 respectively. The

  The frequency lock unit 94 includes the mixer 54, the voltage control oscillator 58, the distributor 60, the m-multiplying PLL oscillator 62, the reception frequency setting circuit 64, and the low-pass filter 66 shown in FIG. 4, and receives the frequency of the voltage control oscillator 58. Synchronize with the CP frequency of channel C.

  The TMCC synchronous detection unit 96 includes a mixer 56 and an n-multiplication PLL oscillator 68 shown in FIG. 4, obtains a phase difference signal between the TMCC signal and the output of the n-multiplication PLL oscillator 68, and supplies the phase difference signal to the low-pass filter 100.

  The low-pass filter 100 has the same frequency characteristic as that of the low-pass filter 80 and is of the sinc (πf) = sin (πf) / πf type. The baseband TMCC signal is extracted from the phase difference signal and sent to the emergency warning bit detection unit 102. Supply.

  The emergency warning bit detection unit 102 includes a g / (g + 1) multiplier 72, a TMCC differential pattern generation circuit 74, a correlation reception circuit 76, and an EWS detection circuit 78 shown in FIG. When it is detected that is “with start-up control”, a switch-on signal is output. When this switch-on signal is supplied, the switch 106 is turned on, and the power source 104 is connected to the digital terrestrial television broadcast tuner 98 and the receiver 108, so that an emergency warning broadcast can be received.

FIG. 7 shows a circuit configuration diagram of a second embodiment of the transmission control signal receiver of the present invention. In the figure, an antenna reception signal is supplied to a TMCC dedicated receiver 109 serving as a transmission control signal receiver, amplified by an amplifier 112 of a TMCC quadrature detection circuit 110, and then distributed by a distributor 114 to be supplied to mixers 116 and 118. Supplied. The oscillator 120 oscillates at a frequency f _TMCC that is any one of TMCCl to TMCC4 in the segment 0 within the band of the reception channel C. This oscillation signal is supplied to the mixer 116, and is phase-shifted by π / 2 by the phase shifter 122 and supplied to the mixer 118. As a result, the I signal is output from the mixer 116 and the Q signal is output from the mixer 118.

  The IQ signal is supplied to the guard correlation circuit 124 and the low pass filter 126. The guard correlation circuit 124 slides the guard interval shown in FIG. 8A for each IQ signal to correlate with the data on the back side of the effective symbol period, thereby obtaining the start timing of the guard interval shown in FIG. 8B. The switching signal shown in FIG. 8C having a period T (= Ta + Tg), which is detected and is at a high level in the effective symbol period Ta and at a low level in the guard interval period Tg, is generated. Are supplied to the switches 128 and 130 corresponding to.

  The low-pass filter 126 has a normalized frequency characteristic of sinc (πf) = sin (πf) / πf type. The switch 128 is connected to the capacitor 132 when the switching signal is at a high level, and is connected to the ground side when the switching signal is at a low level, so that the effective symbol period Ta of the I signal is integrated by the capacitor 132 as shown in FIG. . Similarly, the switch 130 is connected to the capacitor 134 when the switching signal is at a high level, and is connected to the ground side when the switching signal is at a low level, whereby the effective symbol period Ta of the Q signal is integrated by the capacitor 134.

  Therefore, an IQ signal having a component of sin (πf / fa) / (πf / fa) is taken out and sampled and held by the sampling and holding circuits (S / H) 136 and 138 as shown in FIG. , DBPSK (Differential Binary Phase Shift Keying) delay detection circuit 140 is supplied.

  In the DBPSK delay detection circuit 140, the I signal is delayed by one symbol time directly and by the delay unit 146 and supplied to the subtractor 142, and the difference signal ΔI obtained here is supplied to the calculator 150. Similarly, the Q signal is delayed by one symbol time directly and by the delay unit 148 and supplied to the subtracter 144, and the difference signal ΔQ obtained here is supplied to the calculator 150.

The calculator 150 calculates (ΔI ² + ΔQ ² ) ^1/2 from the difference signals ΔI and ΔQ as shown in FIG. The determiner 152 makes a determination by comparing (ΔI ² + ΔQ ² ) ^1/2 as shown in FIG. 9B with a predetermined threshold (indicated by a dashed line I in the figure), and DBPSK delay detection is performed. The TMCC signal is output. The TMCC signal is supplied to the EWS detection circuit 154, where the presence / absence of the 26th bit emergency warning broadcast activation flag of the TMCC signal is constantly monitored. When the EWS detection circuit 154 detects that the value of the emergency warning broadcast activation flag is “1: with activation control”, it outputs a switch-on signal.

For the oscillator 120, a circuit similar to the mixer 54, the voltage controlled oscillator 58, the distributor 60, and the m-multiplying PLL oscillator 62 shown in FIG. 5 is added, and the frequency f _TMCC output from the oscillator 120 is received by the receiving channel. It is good also as a structure synchronized with the frequency of CP of C.

  The power consumption of the TMCC dedicated receiver 109 in FIG. 7 is about the same as that in FIG.

  FIG. 10 shows a block diagram of a second embodiment of a digital terrestrial television broadcast receiver to which the TMCC dedicated receiver of FIG. 7 is applied. In the figure, the same parts as those in FIG. In FIG. 10, the antenna reception signal from the reception antenna 160 is distributed by the distributor 162 and supplied to the TMCC quadrature detection circuit 110 and the terrestrial digital television broadcast tuner 164 in the TMCC dedicated receiver 109.

  The TMCC dedicated receiver 109 is configured as shown in FIG. 7 and is always supplied with power from the power source 166, and outputs a switch-on signal when it detects that the value of the emergency warning broadcast activation flag is “with activation control”. When the switch-on signal is supplied, the switch 168 is turned on, and the power source 166 is connected to the terrestrial digital television broadcast tuner 164 and the receiver 170 so that an emergency warning broadcast can be received.

  FIG. 11 shows a block diagram of a third embodiment of the transmission control signal receiver of the present invention. In the figure, an antenna reception signal is supplied to a TMCC dedicated receiver 179 as a transmission control signal receiver, amplified by an amplifier 180, and then distributed by a distributor 182 to receive TMCC dedicated receivers 184, 185, 186, 187. Supplied to each.

  Each of the TMCC dedicated receiving units 184 to 187 includes a TMCC quadrature detection circuit 110, a guard correlation circuit 124, a low-pass filter 126, and a DBPSK delay detection circuit 140 excluding the EWS detection circuit 154 from FIG. However, the oscillator 120 of the quadrature detection circuit 110 oscillates at the TMCCl frequency in the TMCC dedicated receiver 184, oscillates at the TMCC2 frequency in the TMCC dedicated receiver 185, and oscillates at the TMCC3 frequency in the TMCC dedicated receiver 186. The TMCC dedicated receiving unit 187 oscillates at the frequency of TMCC4.

  TMCC signals output from the TMCC dedicated receiving units 184 to 187 are supplied to the majority circuit 188. The majority circuit 188 makes a majority decision for each of the four TMCC signals on a symbol basis, and outputs the resulting TMCC signal. The TMCC signal is supplied to the EWS detection circuit 190, where the presence or absence of the 26th bit emergency warning broadcast activation flag of the TMCC signal is constantly monitored. When the EWS detection circuit 190 detects that the value of the emergency warning broadcast activation flag is “1: with activation control”, it outputs a switch-on signal.

  According to this embodiment, the TMCC signal detection accuracy is further increased by performing a majority decision of the four TMCC signals.

  12 shows a block diagram of a variation of the transmission control signal receiver of FIG. 11 of the present invention. In FIG. 12, the TMCC dedicated receiver 191 is different from the TMCC dedicated receiver 179 of FIG. 11 in that a TMCC pattern correlation receiving circuit 192 is provided between the majority circuit 188 and the EWS detection circuit 190. The TMCC pattern correlation receiving circuit 192 receives the correlation between the known TMCC differential demodulation reference 1 bit, the synchronization signal 16 bits, and the segment format identification 3 bits for a total of 20 bits with respect to the TMCC signal of the majority decision result. Only when it is obtained, the 26th bit emergency warning broadcast activation flag of the TMCC signal is supplied to the EWS detection circuit 190.

  According to this embodiment, the detection accuracy of the emergency warning broadcast activation flag is further increased by checking the TMCC pattern correlation.

  In addition, although the digital terrestrial television broadcasting has been described as being broadcast in mode 3, when it is broadcast in mode 2, equation (1A) is used instead of equation (1), and (4 · 1 ) To (4 · 4) instead of the equations (4 · 1A) and (4 · 2A), and it is clear that the present invention can be applied to other modes as well.

fo = 1000000/504 [Hz] (1A)
n = 3024 · C + 199067 (4.1A)
n = 3024 · C + 199222 (4.2 A)
In the above embodiment, the emergency warning broadcast activation flag is received by the TMCC dedicated receiver as an example. However, transmission for receiving AC (Auxiliary Channel) that transmits additional information related to transmission control of the modulated wave and the like. The present invention may be applied to a control signal receiver and is not limited to the above embodiment. Further, the present invention can be applied to obtaining the probability of normal reception of a total of 20 bits including the TMCC differential demodulation reference 1 bit, the synchronization signal 16 bits, and the segment format identification 3 bits, and evaluating the reception state from the probability.

  The TMCC quadrature detection circuit 110 corresponds to the detection means described in the claims, the guard correlation circuit 124 and the low-pass filter 126 correspond to the transmission control signal component extraction means, and the DBPSK delay detection circuit 140 corresponds to the delay detection means. The guard correlation circuit 124 corresponds to the synchronous reproduction means, the low-pass filter 126 corresponds to the filter means, the majority circuit 188 corresponds to the majority decision means, the TMCC pattern correlation reception circuit 192 corresponds to the correlation reception means, and the mixer 54, a voltage controlled oscillator 58, a distributor 60, an m-multiplication PLL oscillator 62, and a reception frequency setting circuit 64 correspond to the reference frequency signal generation means, and a mixer 56 and an n-multiplication PLL oscillator 68 correspond to the detection means. 70 corresponds to transmission control signal component extraction means, g / (g + 1) multiplier 72, TMCC differential pattern generation circuit 7 , The correlation receiver circuit 76 corresponding to the correlation receiver.

It is a block diagram of an example of the conventional analog television broadcast receiver. It is a block diagram of an example of a demodulation system of a terrestrial digital television broadcast receiver. 1 is a block diagram of an embodiment of a digital terrestrial television broadcast receiver to which a transmission control signal receiver of the present invention is applied. It is a block diagram of 1st Embodiment of the transmission control signal receiver of this invention. It is a block diagram of the modification of the transmission control signal receiver of FIG. 4 of this invention. 1 is a block diagram of a first embodiment of a digital terrestrial television broadcast receiver to which a TMCC dedicated receiver of the present invention is applied. FIG. It is a circuit block diagram of 2nd Embodiment of the transmission control signal receiver of this invention. It is a signal waveform diagram of each part of the circuit of FIG. It is a figure for demonstrating DBPSK delay detection. It is a block diagram of 2nd Embodiment of the digital terrestrial television broadcast receiver to which the receiver only for TMCC of this invention is applied. It is a block diagram of 3rd Embodiment of the transmission control signal receiver of this invention. It is a block diagram of the modification of the transmission control signal receiver of FIG. 11 of this invention.

Explanation of symbols

1, 20, 90, 160 Receiving antenna 3, 28, 108, 170 Receiver 4, 30, 104, 166 Power supply 7, 36, 42, 106, 168 Switch 22, 52, 60, 82, 92, 114, 162 182 Distributor 24, 34, 109, 179, 191 TMCC dedicated receiver 26, 98, 164 Terrestrial digital television broadcast tuner 50 Selective amplifier 54, 56, 116, 118 Mixer 58 Voltage controlled oscillator 62 m-multiplier PLL oscillator 64 Receiving frequency Setting circuit 66, 70, 80, 100, 126 Low-pass filter 68 n multiplier PLL oscillator 72 g / (g + 1) multiplier 74 TMCC differential pattern generator circuit 76 correlation receiver circuit 78, 154, 190 EWS detector circuit 84 Pulse generator 88,132,134 Capacitor 110 TMCC direct Detection circuit 124 guard correlation circuit 140 DBPSK delay detection circuit 184-187 TMCC dedicated receiver 188 voting circuit 192 TMCC pattern correlation receiver circuit

Claims (2)

A reference frequency signal synchronized with the frequency of the pilot carrier at the upper end of the reception channel signal band of digital terrestrial television broadcasting is generated, and the reception channel signal and a transmission control signal frequency signal generated from the reference frequency signal are mixed. obtain a transmission control signal carrier Te extracts before Stories transmission control signal component is a low-frequency component of the transmission control signal carrier, and the transmission control signal component, the transmission control signal generated based on the reference frequency signal A transmission control signal receiver that obtains a transmission control signal from correlation with a synchronization signal pattern ,
Based on the reference frequency signal synchronized with the frequency of the pilot carrier at the upper end of the band of the reception channel signal of the terrestrial digital television broadcast, the transmission control signal of the same frequency as the transmission control signal included in the reception channel signal of the terrestrial digital television broadcast Detecting means for generating a frequency signal and mixing the reception channel signal and the frequency signal to obtain a transmission control signal carrier;
Synchronous reproduction means for reproducing symbol synchronization from the transmission control signal carrier to obtain a symbol synchronization signal, switching based on the symbol synchronization signal, integrating the transmission control signal carrier with a capacitor, The transmission control signal component, which is a low frequency component, has a normalized frequency characteristic.
sinc (πf) = sin (πf) / πf
Transmission control signal component extracting means having filter means for extracting with a low-pass filter,
A dedicated receiver for transmission control signals,
Majority determination means for determining the majority of transmission control signals obtained by four systems of dedicated receivers for transmission control signals;
Correlation receiving means for correlating and receiving the transmission control signal determined by majority decision by the majority decision determining means with the synchronization signal pattern of the transmission control signal;
With
The correlation receiving means performs correlation reception of the transmission control signal determined by majority decision with a differential demodulation reference 1 bit of a known transmission control signal, a synchronization signal of 16 bits, and a segment format identification of 3 bits, and a correlation is obtained. The transmission control signal receiver characterized by outputting an emergency warning broadcast activation flag in the transmission control signal determined by majority decision only in the case . A terrestrial digital television broadcast receiver comprising the transmission control signal receiver according to claim 1 ,
When the transmission control signal receiver detects an emergency warning broadcast activation flag in the transmission control signal, power is supplied to the tuner of the digital terrestrial television broadcast receiver based on the detection result. Television broadcast receiver.

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