JP2006049940A - Terrestrial digital broadcast reception circuit and terrestrial digital broadcast reception method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terrestrial digital broadcast reception apparatus capable of executing channel search of a broadcast channel in a short period of time, and a terrestrial digital broadcast reception method. <P>SOLUTION: A tuner circuit section 12 receives the signal of a designated broadcast channel. Succeedingly, a synchronization establishment section 132 and a tuner control circuit 135 discriminate whether or not the received signal includes a terrestrial digital broadcast signal. The discrimination results are stored in a synchronization establishment station storage memory 136 in association with the designated broadcast channel number. Then a tuner control circuit 135 repeats the reception of the frequency of a broadcast channel other than the designated broadcast channel every time the discrimination result is stored. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a terrestrial digital broadcast receiving circuit and a terrestrial digital broadcast receiving method used for receiving a digitally modulated terrestrial broadcast.

  Terrestrial digital broadcasting started in December 2003, and is currently in a transitional stage from terrestrial analog television broadcasting to terrestrial digital television broadcasting. In terrestrial digital television broadcasting, since OFDM (Orthogonal Frequency Division Multiplexing) is used as a modulation method, a plurality of radio waves (specifically, video, audio, data broadcasting, etc.) are generated. Multiplexed and transmitted.

  As such a terrestrial digital television broadcast receiving circuit, a terrestrial digital broadcast receiving circuit 9 as shown in FIG. 4 is generally used. The terrestrial digital broadcast receiving circuit 9 includes an antenna 11, a tuner circuit unit 91, a demodulation circuit unit 92, a decoder unit 14, and the like. The demodulation circuit unit 92 includes an analog / digital converter (ADC) 131, a synchronization establishment unit 921, a demodulation unit 133, an error correction unit 134, and the like.

  The radio wave received by the antenna 11 is amplified and tuned to a desired broadcast wave by the tuner circuit unit 91 and output to the demodulation circuit unit 92 as a broadcast wave signal. The broadcast wave signal input to the demodulation circuit unit 92 is subjected to analog / digital conversion by the ADC 131, subjected to synchronous reproduction by orthogonal demodulation by the synchronization establishment unit 921, and demodulated by the demodulation unit 133. The demodulated signal is subjected to error correction processing such as time deinterleaving in the error correction unit 134 and output to the decoder unit 14 as a TS (Transport Stream).

  The decoder unit 14 performs a decoding process on this TS and outputs it to the outside of the terrestrial digital broadcast receiving circuit 9. A device (not shown) incorporating the terrestrial digital broadcast receiving circuit 9 performs image display and audio output as a television broadcast using this output signal.

  In such a terrestrial digital broadcast receiver circuit 9, the tuner circuit unit 91 is synchronized with a desired broadcast wave and outputs a stable broadcast wave signal for about 0.1 second (A). Is about 0.3 seconds (B), about 0.4 seconds (C) for error correction processing by the error correction unit 134, and about 0.5 seconds (D) for TS decoding processing by the decoder unit 14. Is known to require. That is, when switching broadcast channels, it takes about 1.3 seconds (A + B + C + D) to display the screen after the operation.

  Generally, a technique is known in which a local transmission frequency is set to the center frequency of a channel band when a broadcast channel is selected so that a tuner can extract an entire channel band including a plurality of broadcast services in a short time. (See Patent Document 1).

  For example, when a receiving circuit such as a terrestrial digital broadcast receiving circuit 9 is mounted on a mobile phone or a mobile receiver, if the terrestrial digital broadcast receiving circuit 9 moves, each broadcast channel in the destination area It is necessary to check for the presence of broadcast waves (channel search). For example, since there are 50 broadcast channels in the UHF band used for terrestrial digital television broadcasting, it takes about 40 seconds ((A + B + C) × 50) to perform error correction processing from tuning processing for all channels. Note that switching of broadcast channels in the channel search is performed by inputting a switching instruction signal from a CPU or the like. Thus, channel search took too much time and was not practical.

Therefore, information on a broadcasting station that broadcasts the TS and information on broadcasting stations in all broadcasting areas adjacent to the broadcasting area of the broadcasting station are described in a NIT (Network Information Table) and broadcasted. The receiving device includes first and second receiving units, and by receiving the NIT, the first receiving unit monitors the radio wave condition of the broadcast channel in the current broadcast area, and the second receiving unit There has also been proposed a digital broadcasting method and a receiving apparatus thereof for monitoring a radio wave condition of a broadcast channel in a broadcast area adjacent to the broadcast area (see Patent Document 2).
JP 2001-320640 A JP 2002-359825 A

  However, in the case of the technique as disclosed in Patent Document 2, NIT cannot be acquired if the selected broadcast channel cannot be received in the first place. Therefore, it is necessary to switch the reception channel until the broadcast wave can be accurately received. For this reason, in areas where it is difficult to receive many broadcast channels, it is difficult to obtain the NIT, which eventually takes a long time.

  Furthermore, it is necessary to provide two receiving units, a receiving unit that monitors the radio wave condition of the current broadcasting area and a receiving unit that monitors the radio wave condition of the broadcasting area adjacent to the current broadcasting area. For this reason, the circuit area and cost of the receiving apparatus increase, and it is not suitable for a small mobile receiver such as a mobile phone.

  The present invention has been made in consideration of the above points, and an object of the present invention is to provide a terrestrial digital broadcast receiving apparatus and a terrestrial digital broadcast receiving method capable of performing a channel search of a broadcast channel in a short time. It is to be.

  In order to solve the above problems, the terrestrial digital broadcast receiving circuit according to the first aspect of the present invention includes a receiving unit (for example, the tuner circuit unit 12 in FIG. 1) that receives a signal of a frequency of a designated broadcast channel. A determination unit (for example, the synchronization establishment unit 132 and the tuner control circuit 135 in FIG. 1) that determines whether or not the terrestrial digital broadcast signal is included in the signal received by the reception unit, and the determination by the determination unit A storage unit (for example, the synchronization establishment station storage memory 136 in FIG. 1) that stores the result and the broadcast channel number designated by the reception unit in association with each other, and each time the determination result is stored in this storage unit In addition, a control unit (for example, the tuner control circuit 13 in FIG. 1) that repeats an operation of controlling the receiving unit to receive a frequency of a broadcast channel different from the designated broadcast channel. ) And it is characterized by having a.

  The invention according to claim 2 is the terrestrial digital broadcast receiving circuit according to claim 1, wherein the determination unit extracts a synchronization signal from a signal received by the receiving unit and establishes synchronization. It includes an establishing unit (for example, the synchronization establishing unit 132 in FIG. 1), and determines whether the received signal includes a terrestrial digital broadcast signal depending on whether the synchronization establishing unit has established synchronization. It is characterized by that.

  The invention according to claim 3 is the terrestrial digital broadcast receiving circuit according to claim 1, wherein the control unit specifies a preset broadcast channel in response to power-on, and thereafter the storage unit Each time the determination result is stored, the operation of controlling the receiving unit to receive a frequency of a broadcast channel different from the designated broadcast channel is repeated until the frequencies of all broadcast channels are received. It is characterized by.

  According to a fourth aspect of the present invention, there is provided a terrestrial digital broadcast receiving method comprising: a receiving step (for example, the tuner circuit unit 12 in FIG. 1) for receiving a signal of a frequency of a designated broadcast channel; Determination step for determining whether or not a terrestrial digital broadcast signal is included (for example, synchronization establishment unit 132 and tuner control circuit 135 in FIG. 1, step S13 in FIG. 3), determination result in this determination step, and the designation A storing step (for example, synchronization establishment station storage memory 136 in FIG. 1, step S14 and step S16 in FIG. 3) for storing the channel number in association with each other, and each time the determination result is stored in this storing step , A control process for controlling the frequency of the designated broadcast channel to be the frequency of another broadcast channel (for example, the tuner control circuit 1 in FIG. 1) 5, and having a, and step S18) in FIG.

  The invention according to claim 5 is the terrestrial digital broadcast receiving method according to claim 4, wherein the determination step extracts synchronization signals from the signals received in the reception step and establishes synchronization. A step of determining whether or not the received signal includes a terrestrial digital broadcast signal depending on whether or not synchronization is established in the synchronization establishment step, including an establishment step (synchronization establishment unit 132 in FIG. 1). It is characterized by being.

  The invention according to claim 6 is the terrestrial digital broadcast receiving method according to claim 4, wherein the control step is a step of designating a preset broadcast channel when the power is turned on (for example, step of FIG. 3). S11), and thereafter, every time the determination result is stored in the storage step, the step of setting the frequency of the designated broadcast channel to the frequency of another broadcast channel (for example, step S18 in FIG. 3) It is the process of repeating until it receives the frequency of this.

  According to the terrestrial digital broadcast receiving circuit according to claim 1 and the terrestrial digital broadcast receiving method according to claim 4, the terrestrial digital broadcast receiving method is specified based on the TS output from the terrestrial digital broadcast receiving circuit as in the prior art. The determination can be made in the terrestrial digital broadcast receiving circuit without determining the presence or absence of the broadcast wave of the channel. Further, there is no need for external control such that an external circuit (for example, CPU) or the like performs broadcast channel switching control on the receiving unit. That is, every time the determination result of the broadcast wave presence / absence of the broadcast channel is stored, the control unit instructs the switching of the broadcast channel, and the determination is performed. For this reason, for example, it is possible to significantly reduce the time spent for channel search time such as checking for the presence or absence of broadcast waves for all UHF broadcast channels.

  According to the terrestrial digital broadcast receiving circuit according to claim 2 and the terrestrial digital broadcast receiving method according to claim 5, the presence / absence of the broadcast wave of the designated broadcast channel is determined depending on whether synchronization is established. Is called. As a result, there is no need to perform demodulation processing and error correction processing in order to determine the presence / absence of broadcast waves in a broadcast channel as in the prior art. For example, a channel search for checking the presence / absence of broadcast waves for all UHF broadcast channels is performed. Time spent on time can be significantly reduced.

  According to the terrestrial digital broadcast receiving circuit according to claim 3 and the terrestrial digital broadcast receiving method according to claim 6, an external circuit (for example, a CPU) or the like performs broadcast channel switching control on the receiving unit. There is no need for external control. That is, every time the determination result of the broadcast wave presence / absence of the broadcast channel is stored, the control unit instructs the switching of the broadcast channel, and the determination is performed. For this reason, for example, it is possible to significantly reduce the time spent for channel search time such as checking for the presence or absence of broadcast waves for all UHF broadcast channels.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, although the case where this invention is applied to the terrestrial digital broadcast receiving circuit for receiving terrestrial digital television broadcast is demonstrated, the form which can apply this invention is not limited to this. Also, the same components as those in the terrestrial digital broadcast receiving circuit 9 described with reference to FIG.

  FIG. 1 is a block diagram of the main part of a terrestrial digital broadcast receiver. The terrestrial digital broadcast receiving apparatus includes a terrestrial digital broadcast receiving circuit 1, a CPU 2, and the like. The terrestrial digital broadcast receiving circuit 1 is an antenna 11 that receives radio waves, a tuner circuit unit 12 that amplifies the radio waves received by the antenna 11 and tunes to a desired frequency, and a signal output from the tuner circuit unit 12 A demodulating circuit unit 13 that mainly performs processing such as digital demodulation and error correction and outputs a TS, and a decoder unit 14 that performs decoding processing on the TS are configured.

  Further, the tuner circuit unit 12 includes an LNA (Low Noise Amplifier) 121, AGCs 122 and 126, BPF (Band Pass Filter) 123 and 125, an RF mixer 124, an IF mixer 127, and an LPF (Low Pass Filter). A low-pass filter) 128.

  The radio wave received by the antenna 11 is first amplified by the LNA 121 and the AGC 122 with a predetermined amplification factor. The signal output from the AGC 122 is cut out only in a predetermined frequency band by the BPF 123, and further converted into an intermediate frequency signal having a predetermined center frequency by the RF mixer 124. The signal output from the RF mixer 124 is cut out only in a predetermined frequency band by the BPF 125 and amplified by the AGC 126. The signal output from the AGC 126 is converted into a broadcast wave signal having a predetermined center frequency by passing through the IF mixer 127 and the LPF 128.

  The demodulation circuit unit 13 includes an ADC 131, a synchronization establishment unit 132, a demodulation unit 133, an error correction unit 134, a tuner control circuit 135, a synchronization establishment station storage memory 136, and the like. The demodulation circuit unit 13 receives the broadcast wave signal output from the tuner circuit unit 12 and performs analog / digital conversion by the ADC 131. The signal output from the ADC 131 is subjected to synchronous reproduction by orthogonal demodulation by the synchronization establishing unit 132 and demodulated by the demodulating unit 133. The demodulated signal is subjected to error correction processing such as time deinterleaving in the error correction unit 134 and output to the decoder unit 14 as a TS.

  When synchronization is established for the signal input from the ADC 131, the synchronization establishing unit 132 outputs a synchronization establishment signal S2. Based on the synchronization establishment signal S2, the tuner control circuit 135 stores in the synchronization establishment station storage memory 136 whether or not the broadcast wave of the designated channel is included in the currently received signal, and the synchronization frequency is set to the next channel. The instruction signal S1 is output to the tuner circuit unit 12 in order to switch to the frequency. Further, when it is determined that synchronization is established for all channels, the stored contents of the synchronization establishment station storage memory 136 are output to the CPU 2. The tuner control circuit 135 includes a timer circuit (not shown).

  The decoder unit 14 performs decoding processing on the TS output from the demodulation circuit unit 13 and outputs it, and the terrestrial digital broadcast receiver performs image display and audio output as a television broadcast.

  The CPU 2 outputs a signal for instructing the start of the channel search to the tuner control circuit 135, and performs processing such as acquiring the storage contents of the synchronization establishment station storage memory 136 via the tuner control circuit 135.

  FIG. 2 is a diagram for explaining an example of the contents stored in the synchronization establishment station storage memory 136. In the synchronization establishment station storage memory 136, the determination result of the presence / absence of broadcast waves of all channels subjected to channel search is, for example, “1” when there is a broadcast wave, and “0” when there is no broadcast wave (00) H. It is stored in order from the address. For example, when the synchronization establishment signal S2 is output while receiving the channel 1, "1" is stored at address (00) H. If the synchronization establishment signal S2 is not output within a predetermined time during reception of the channel 2, “0” is stored at address (01) H. When there are 50 broadcast channels, the determination result of channel 50 is stored at address (31) H.

  After the presence / absence of broadcast waves is determined for all channels, the content stored in the synchronization establishment station storage memory 136 is output to the CPU 2. The CPU 2 performs processing such as outputting a channel table to a display unit (not shown) or the like of the terrestrial digital broadcast receiving apparatus based on the input contents of the synchronization establishment station storage memory 136. As a result, the user can immediately determine which channel can be viewed.

  FIG. 3 is a flowchart for explaining the flow of circuit operations of the tuner circuit unit 12, the tuner control circuit 135, and the CPU 2. When the CPU 2 detects that the terrestrial digital broadcast receiving apparatus is powered on (step S21; Yes), or when it detects a channel search operation input (step S22; Yes), the tuner receives a signal for instructing the start of the channel search. The data is output to the control circuit 135 (step S23).

  When receiving an instruction signal from the CPU 2, the tuner control circuit 135 outputs an instruction signal S1 for switching the reception channel to the initial channel to the tuner circuit unit 12 (step S11). When receiving the instruction signal S1, the tuner circuit unit 12 sets the tuning frequency to the initial channel (for example, the channel having the lowest (or highest) frequency) (step S31).

  The tuner control circuit 135 resets the timer and starts counting by the timer circuit (step S12). The timer time is about several tens [m seconds], for example. Next, the tuner control circuit 135 determines whether or not the synchronization establishment signal S2 is input from the synchronization establishment unit 132 (step S13). When the synchronization establishment signal S2 is input (step S13; Yes), the tuner control circuit 135 sets “1” to the memory area of the synchronization establishment station storage memory 136 corresponding to the channel currently received in the synchronization establishment station storage memory 136. Store (step S14).

  On the other hand, when the synchronization establishment signal S2 is not input (step S13; No), the tuner control circuit 135 determines whether the count by the timer circuit is finished (step S15). When the timer count has not ended (step S15; No), the process of step S13 is repeated.

  When the timer count is completed (step S15; Yes), the tuner control circuit 135 stores “0” in the memory area of the synchronization establishment station storage memory 136 corresponding to the channel currently being received in the synchronization establishment station storage memory 136. (Step S16).

  Next, the tuner control circuit 135 determines whether or not channel search has been completed for all channels (step S17). When the channel search is in progress (step S17; No), the tuner control circuit 135 outputs an instruction signal S1 for switching to the next channel to the tuner circuit unit 12 (step S18). When receiving the instruction signal S1, the tuner circuit unit 12 sets the tuning frequency to the next channel (step S32). On the other hand, when the channel search is completed (step S17; Yes), the tuner control circuit 135 outputs the stored contents of the synchronization establishment station storage memory 136 to the CPU 2 (step S19).

  As described above, it is determined based on the synchronization establishment signal S2 whether or not the received signal includes the broadcast wave of the designated channel. Each time the determination result is stored in the synchronization establishment station storage memory 136, the tuner circuit unit 12 is automatically instructed to switch the tuning frequency to the next channel, thereby interposing an external circuit such as the CPU 2. It is possible to perform a channel search while switching channels one after another. For this reason, a channel search can be performed in a short time.

  Specifically, as described above, the tuner circuit unit 12 is synchronized with a desired broadcast wave and outputs a stable broadcast wave signal for about 0.1 second (A), and the synchronization reproduction process by the synchronization establishment unit 132 If it takes about 0.3 seconds (B) and the error correction processing by the error correction unit 134 to take about 0.4 seconds (C), conventionally, at least 0 is required until the presence / absence of the broadcast wave of the designated channel is determined. It took 8 seconds (A + B + C). However, if the present invention is applied, the presence / absence of the broadcast wave of the designated channel is determined by the output of the synchronization establishment signal S2, and therefore, it can be realized in 0.4 seconds (A + B) from channel reception to determination. Therefore, for example, the time spent for channel search such as checking for the presence of broadcast waves for all UHF broadcast channels can be significantly reduced.

The principal part block diagram of the terrestrial digital broadcast receiver which is one Embodiment to which invention is applied. The figure for demonstrating an example of the memory content of the synchronization establishment station | game memory of the terrestrial digital broadcast receiver of FIG. The flowchart for demonstrating the flow of the circuit operation | movement by the tuner circuit part of a terrestrial digital broadcasting receiver, a tuner control circuit, and CPU. The block diagram which shows the conventional terrestrial digital broadcast receiving circuit.

Explanation of symbols

1 Digital Terrestrial Television Broadcasting Reception Circuit 11 Antenna 12 Tuner Circuit 121 LNA
122, 126 AGC
123, 125 BPF
124 RF mixer 127 IF mixer 128 LPF
13 Demodulation circuit 131 ADC
132 synchronization establishment unit 133 demodulation unit 134 error correction unit 135 tuner control circuit 136 synchronization establishment station storage memory 14 decoder unit 2 CPU

Claims (6)

A receiver for receiving a signal of a frequency of a designated broadcast channel;
A determination unit that determines whether or not a terrestrial digital broadcast signal is included in the signal received by the reception unit;
A storage unit for storing the determination result by the determination unit and the broadcast channel number designated by the reception unit in association with each other;
Each time the determination result is stored in the storage unit, a control unit that repeats an operation of controlling the receiving unit to receive a frequency of a broadcast channel different from the designated broadcast channel;
A terrestrial digital broadcast receiving circuit.   The determination unit includes a synchronization establishment unit that extracts a synchronization signal from the signal received by the reception unit and establishes synchronization, and determines whether the synchronization establishment unit has established synchronization, 2. The terrestrial digital broadcast receiving circuit according to claim 1, wherein it is determined whether or not a digital wave broadcast signal is included.   The control unit designates a preset broadcast channel in response to power-on, and each time the determination result is stored in the storage unit thereafter, the control unit is different from the designated broadcast channel. 2. The terrestrial digital broadcast receiving circuit according to claim 1, wherein the operation of controlling to receive the frequencies of the broadcast channels is repeated until the frequencies of all the broadcast channels are received. A receiving process for receiving a signal of a frequency of a designated broadcast channel;
A determination step of determining whether a terrestrial digital broadcast signal is included in the signal received in the reception step;
A storage step of storing the determination result in the determination step and the number of the designated broadcast channel in association with each other;
A control step of performing control to set the frequency of the designated broadcast channel to a frequency of another broadcast channel each time the determination result is stored in the storage step;
A terrestrial digital broadcast receiving method.   The determination step includes a synchronization establishment step of extracting a synchronization signal from the signal received in the reception step to establish synchronization, and the received signal is grounded depending on whether synchronization is established in the synchronization establishment step. The terrestrial digital broadcast receiving method according to claim 4, which is a step of determining whether or not a digital wave broadcast signal is included.   The control step includes a step of designating a preset broadcast channel when the power is turned on, and each time the determination result is stored in the storage step, the frequency of the designated broadcast channel is set as the frequency of another broadcast channel. The terrestrial digital broadcast receiving method according to claim 4, wherein the step of repeating is a step of repeating until the frequencies of all broadcast channels are received.

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