JP2008053968A - Terrestrial digital voice broadcast receiver and its channel selection control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terrestrial digital voice method receiver and its channel selection control method capable of shortening a channel selection time. <P>SOLUTION: The channel selection control method comprises the steps of: dividing a frequency of a segment outputted from a frequency selection means into a sub channel unit by filter means; measuring a received power in the sub channel unit; comparing the measured received power of each sub channel with a predetermined threshold; determining receiving propriety of the segment from the result of the comparison based on combination of the measured result (received power) of each sub channel, and judging that there is no broadcasting without performing OFDM demodulation; computing difference between the center frequency of the segment and the center frequency of an original segment, if it is judged that there is no broadcasting; and computing the center frequency of a segment which performs a receiver operation next based on the computed difference. Therefore, unnecessary channel selection processing can be avoided for a segment of a center frequency which can be judged as reception impossible in advance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a terrestrial digital audio broadcasting receiver and a channel selection control method thereof, and more particularly, to a terrestrial digital audio method receiver and a channel selection control method thereof that reduce channel selection time.

  2. Description of the Related Art Conventionally, in a television broadcast or radio broadcast receiver, receivable broadcast information is generally set in the receiver at the installation location of the receiver. These operations are referred to as channel scanning and the like. Specifically, reception of all channels is confirmed in order, and information on channels determined to have receivable broadcasts is set in the receiver.

  There is also a receiver having a search channel selection means for receiving a channel in order and viewing on a receivable channel, and a means for registering a receivable channel found by the search channel selection by a user operation.

  In particular, it is a broadcast receiver that can be used when moving, and it is necessary to perform channel scanning even when the channel that can be received changes due to movement in a receiver that sets channel information that can be received by performing channel scanning. It is desirable to perform channel scanning as fast as possible.

  However, in terrestrial digital broadcasting and terrestrial digital audio broadcasting, more time is required for channel scanning and search channel selection than in conventional analog broadcasting. This is because, in the case of terrestrial digital broadcasting or terrestrial digital audio broadcasting, the OFDM method is used as the transmission method, so that frame synchronization time of the OFDM signal is required for confirmation of reception.

  For this reason, Patent Document 2 proposes a method in which two tuners are installed and reception is confirmed simultaneously in the reverse order by the two tuners. In this method, the channel scan time can be reduced to about half, but it may not be possible to mount the two tuners on the receiver due to the mounting area and power consumption.

  Therefore, as a technique for speeding up channel scanning and search channel selection, it is determined that there is no broadcast that can be received when the reception level of the channel selected for channel selection time is lower than a predetermined value. Many methods have been proposed to reduce the channel selection time by reducing the number of channels for performing detailed reception confirmation operations.

  In Patent Document 1, the pass bandwidth of the first intermediate frequency signal tuning stage is selected to be a wide bandwidth for passing a plurality of segment groups, for example, 6 MHz, and the pass bandwidth of the second intermediate frequency signal tuning stage is set to a plurality of segments. A part of a plurality of segment groups is adjacent by selecting and extracting a part of the plurality of segment groups by fine-tuning the oscillation frequency of the second local oscillator by selecting a narrow bandwidth for passing a part of the group. A terrestrial digital broadcast reception tuner has been proposed that can effectively select and extract a part of a plurality of segment groups in a state in which the influence of a high-level analog broadcast electric field is minimized even when close to an analog broadcast channel. .

  In Patent Document 3, a first frequency divider that divides the reference signal output from the reference oscillator and supplies a comparison signal to the first PLL circuit is provided, and the oscillation frequency of the reference oscillator is set to the second local oscillation signal. Comparison of the first PLL circuit by setting the frequency division ratio of the first frequency divider to 2/7 of the frequency of the second local transmission signal in MHz A terrestrial digital broadcast receiving tuner that can set the frequency of a signal to (1/7) MHz and can receive an arbitrary segment has been proposed.

  In Patent Document 4, the frequency data supplied to the PLL is corrected based on the difference between the measured value of the frequency of the intermediate frequency signal obtained by converting the broadcast signal of the selected channel and the reference value of the frequency of the intermediate frequency signal. Thus, there has been proposed a frequency data generating apparatus that can reduce the number of times frequency data is transmitted to the PLL before reaching an optimum reception state and can reduce the time required for channel selection.

  In Patent Document 5, the presence / absence of broadcast waves is detected over a frequency band corresponding to a plurality of broadcast channels by a very simple process, independent of the process in the main system for demodulating the broadcast wave signal. The time spent on operations such as switching to a broadcast channel that is being broadcast near or next to the channel being received (before or after) or checking the presence or absence of broadcast wave output for all broadcast channels in the UHF is significantly reduced. An OFDM signal receiving apparatus and an OFDM signal receiving method that can be used have been proposed.

Patent Document 6 is a reception device that includes a front end that receives an RF signal, a filter that passes an output signal, and a demodulator that outputs a transport stream, and can receive at least terrestrial digital data. Can be tuned to multiple frequency channels of the received signal, and the filter can pass multiple frequency channels to determine whether the received power of each frequency channel in the multiple frequency channels exceeds a threshold value. In order to determine whether or not it is a terrestrial digital signal that can be received only for a frequency channel whose received power exceeds a threshold value, a receiving apparatus that performs frequency scanning has been proposed.
JP 2001-346110 A JP 2004-112079 A JP 2005-033553 A JP 2005-109561 A JP 2005-244481 A JP 2005-347937 A

  However, the above invention has the following problems.

  The conventional method for determining the reception power based on the reception bandwidth cannot correctly check the presence / absence of terrestrial digital audio broadcasting, and cannot speed up channel scanning or channel search. This is because, in terrestrial digital audio broadcasting, even when a frequency at which a broadcast cannot be received correctly is selected, received power for determining that there is a receivable broadcast is detected.

  FIG. 4 shows the frequency arrangement in terrestrial digital audio broadcasting. In terrestrial digital audio broadcasting, the same 6 MHz bandwidth as that of television broadcasting is composed of a minimum unit of 1/7 MHz bandwidth called a subchannel. A band used by one broadcast is composed of segments having a bandwidth of 3/7 MHz with three subchannels as one, and one segment or three consecutive is the minimum unit for data transmission.

  Broadcast waves transmitted from the transmitting station are transmitted in a state where a plurality of 1-segment and 3-segment broadcasts are connected in the same 6 MHz band as that of the television broadcast. As for the arrangement of broadcasts in the 6 MHz band of the connected digital radio broadcast, only the arrangement of 1/7 MHz subchannels as described above is specified, and the segment arrangement of broadcast waves in the band is specified. Not.

  In a tuner of a normal terrestrial digital audio broadcasting receiver, the bandwidth received by the receiver is 3/7 MHz of 1 segment or 9/7 MHz of 3 segments. In the standard, the detailed arrangement of the connected segments in the 6 MHz band is not determined. Therefore, when the tuner selects a channel, the center frequency is specified in order of 1/7 MHz subchannel from the upper or lower side of the band. It is necessary to select a channel.

  For example, when channel selection is performed from a broadcast wave having the segment structure shown in FIG. 5, the center frequency is specified in order for each subchannel, and the reception power is determined by measuring the reception power of the segment having the specified center frequency. judge. However, conventionally, when f1, f2, and f4 are designated as center frequencies, the received power is not detected in all three subchannels constituting the segment, but the received power is received in any one subchannel. Is present, it is erroneously determined that there is a broadcast in the segment. Thereafter, OFDM frame synchronization processing is performed, and it is determined that OFDM frame synchronization cannot be established and there is no broadcast. Therefore, it is necessary to perform unnecessary OFDM frame synchronization processing in order to determine the presence or absence of broadcasting.

  Therefore, the present invention prevents erroneous determination that occurs when detecting the presence or absence of broadcasting by detecting the reception power of each segment in channel scanning in a terrestrial digital audio broadcast receiver, and is required for unnecessary reception operations. An object of the present invention is to propose a terrestrial digital audio broadcasting receiver and a channel selection control method thereof that can reduce the time required for the channel search operation by deleting the time.

  According to a first aspect of the present invention, there is provided a digital terrestrial audio broadcasting receiver having an antenna capable of receiving a digital terrestrial broadcast wave, a frequency selection means for extracting a signal in segment units from the digital terrestrial broadcast wave received by the antenna, and the frequency Dividing means for dividing the segment extracted by the selecting means into a plurality of subchannels, level measuring means for measuring the reception level of each subchannel divided by the dividing means, and the level measuring means Determining means for measuring whether or not the reception level of each subchannel exceeds a threshold, and determining that the digital terrestrial broadcast wave can be received in the segment when the reception levels of all the subchannels exceed the threshold; It is characterized by having.

  According to a second aspect of the present invention, in the terrestrial digital audio broadcasting receiver according to the first aspect, the digital terrestrial digital audio broadcasting receiver has a control means for setting a center frequency of the segment from which a signal is extracted. Further, the segment signal corresponding to the center frequency is extracted.

  According to a third aspect of the present invention, in the terrestrial digital audio broadcast receiver according to the second aspect, when the determination unit determines that the terrestrial digital broadcast wave cannot be received in the segment, the reception level exceeds the threshold. Computation means for calculating a difference between the center frequency of the segment and the center frequency of the segment capable of receiving a terrestrial digital broadcast wave based on the configuration of the subchannel whose channel and reception level did not exceed a threshold. Then, the control means sets the center frequency of the segment from which a signal is next extracted based on the difference calculated by the calculation means.

  According to a fourth aspect of the present invention, in the terrestrial digital audio broadcasting receiver according to any one of the first to third aspects, the dividing unit divides the segment into three subchannels.

  According to a fifth aspect of the present invention, in the terrestrial digital audio broadcasting receiver according to the fourth aspect, the bandwidth of the subchannel is 1/7 MHz.

  The invention described in claim 6 is a channel selection control method for a terrestrial digital audio broadcasting receiver having an antenna capable of receiving a terrestrial digital broadcast wave, and extracts a signal in segment units from the terrestrial digital broadcast wave received by the antenna. A frequency selection step, a division step of dividing the segment extracted by the frequency selection step into a plurality of subchannels, a level measurement step of measuring a reception level of each subchannel divided by the division step, and Measures whether or not the reception level of each subchannel measured by the level measurement process exceeds a threshold, and when the reception level of all the subchannels exceeds the threshold, terrestrial digital broadcast waves can be received in the segment And a determination step for determining.

  A seventh aspect of the present invention is the tuning control method according to the sixth aspect, wherein a control step of setting a center frequency of the segment from which a signal is extracted and the frequency selection step include the center frequency set by the control step. And extracting a signal of the segment corresponding to the above.

  The invention according to claim 8 is the channel selection control method according to claim 7, wherein when the determination step determines that the digital terrestrial broadcast wave cannot be received in the segment, the subchannel whose reception level exceeds a threshold and A calculation step of calculating a difference between the center frequency of the segment and the center frequency of the segment capable of receiving a terrestrial digital broadcast wave based on the configuration of the subchannel whose reception level does not exceed a threshold; and the control The step includes setting the center frequency of the segment from which a signal is next extracted based on the difference calculated by the calculation unit.

  The invention according to claim 9 is the channel selection control method according to any one of claims 6 to 8, wherein the dividing step divides the segment into three subchannels.

  A tenth aspect of the present invention is the tuning control method according to the ninth aspect, wherein the bandwidth of the subchannel is 1/7 MHz.

  In the present invention, the frequency of the segment output from the frequency selection unit is divided into subchannel units by the filter unit, the reception power is measured in units of subchannels, and the measured reception power of each subchannel is set in advance. Is compared to the threshold value, and based on the combination of the measurement results (reception power) of each sub-channel, it is determined that there is no broadcast without performing OFDM demodulation processing by determining whether or not the segment can be received. When it is determined that there is no segment, the difference between the center frequency of the segment and the center frequency of the original segment is calculated. Based on the calculated difference, the center frequency of the segment that performs the next reception operation is calculated in advance. Therefore, unnecessary channel selection processing can be avoided in the segment of the center frequency that can be determined as unreceivable.

  Next, the configuration and operation of the terrestrial digital audio broadcast receiver according to this embodiment will be described.

  First, the configuration of the terrestrial digital audio broadcast receiver according to the present embodiment will be described with reference to FIG.

  The terrestrial digital audio broadcast receiver according to the present embodiment takes out a signal of a desired frequency from a broadcast wave received by the antenna 11, the control means 14, and the antenna with a bandwidth of 1 segment (3/7 MHz). A tuner (frequency selecting means) 12, an OFDM demodulating means 13 for demodulating the extracted frequency signal, and a reproducing means (not shown) for reproducing the demodulated data output from the OFDM demodulating means 13 for video, audio and data broadcasting, respectively. Presenting means (not shown) for presenting the video, audio and data broadcast reproduced by the reproducing means to the user, filter means 17 for further dividing the output signal from the tuner 12, and a level for measuring the output signal level of the filter means 17 Based on the measurement results of the measurement means 16 and the level measurement means 16, the presence / absence of broadcasting and the channel selection frequency Configured with a determination unit 15 a quantity.

  Next, in the digital terrestrial audio broadcast receiver according to the present embodiment, an operation for selecting a channel from the broadcast wave having the segment structure shown in FIG. 5 will be described.

  When the channel selection operation is started, the control unit 14 sets the center frequency of the segment received by the tuner 12. In the channel selection operation, the reception power of each segment is detected in order using the upper or lower subchannel of the reception channel as the center frequency. In the broadcast wave having the segment structure shown in FIG. 5, f1 or f2 is set as the center frequency. This is because one segment composed of three subchannels is the minimum transmission unit, and the center frequency of the uppermost or lower segment of the broadcast wave shown in FIG. 5 corresponds to f1 or f2.

  When f1 is set as the center frequency in the tuner 12, the tuner 12 outputs a signal having a bandwidth of 3/7 MHz with f1 as the center frequency, and notifies the control means 14 of the completion of the frequency selection. When receiving the frequency selection completion notification from the tuner 12, the control unit 14 controls the filter unit 17 and the level measurement unit 16 to measure the received power.

  Here, the operation of measuring the received power in the filling unit 17 and the level measuring unit 16 will be described. The filter means 17 and the level measuring means 16 have the configuration shown in FIG. 2 (a) or (b).

  First, the structure of the filter means 17 and the level measurement means 16 shown to Fig.2 (a) is demonstrated. The BPF 17a is a band-pass filter that passes only the lower 1/7 MHz band of the 3/7 MHz band signal that is the output of the tuner 12. The BPF 17b is a band-pass filter that passes the 1/7 MHz band in the center of the 3/7 MHz band. The BPF 17c is a band pass filter that passes the upper 1/7 MHz band of the 3/7 MHz band. The output signal of the tuner 12 is divided into three signals having a center frequency of 1/7 MHz and a bandwidth of 1/7 MHz by BPF 17a, BPF 17b, and BPF 17c, and input to level measurement 16a, level measurement 16b, and level measurement 16c. Is done. The measurement results of the received power for each 1/7 MHz band in the level measurement 16a, the level measurement 16b, and the level measurement 16c are output from the level measurement unit 16 as measurement results A, measurement results B, and measurement results C, respectively.

  Next, the configuration of the filter unit 17 and the level measuring unit 16 shown in FIG. The filter means 17 is made of a variable BPF and has a pass band of 1/7 MHz. The variable BPF can set the center frequency from the control means 14, and can set the same band as the band set for each BPF shown in FIG.

  When measuring the level of the output signal of the tuner 12, the control means 14 sets the pass band of the variable BPF to the same value as the BPF 17a in FIG. 2A, measures the received power, and outputs the measurement result. . This measurement result corresponds to the measurement result A in FIG. Next, the pass band of the variable BPF is set to the same value as that of the BPF 17b in FIG. 2A, the received power is measured, and the measurement result is output. This measurement result corresponds to the measurement result B in FIG. Next, the pass band of the variable BPF is set to the same value as the BPF 17c in FIG. 2A, the received power is measured, and the measurement result is output. This measurement result corresponds to the measurement result C in FIG. As a result of the above operation, in the configuration of FIG. 2B, the received segment with a bandwidth of 3/7 MHz is obtained in the same manner as the measurement result A, measurement result B, and measurement result C in FIG. It is possible to output the result of measuring the reception power of each subchannel by dividing the subchannel by 1/7 MHz.

  The determination unit 15 determines whether or not broadcast reception is possible in a segment whose center frequency is the frequency set by the control unit 14 from the measurement result of the received power every 1/7 MHz measured by the filter unit 17 and the level measurement unit 16. judge.

  The determination means 15 first determines the presence or absence of a signal for each of the measurement result A, the measurement result B, and the measurement result C. Note that the presence / absence of a signal is determined by comparing a preset threshold value with each measurement result (reception power). For example, when the frequency f1 shown in FIG. 5 is set as the center frequency, it is determined that the measurement result A has no signal, the measurement result B has no signal, and the measurement result C has a signal. Next, a combination of determinations of the measurement result A (no signal), the measurement result B (no signal), and the measurement result C (with a signal) is applied to the table shown in FIG. 6, and the determination result (unreceivable) is output. At the same time, from the combination of the measurement result A (no signal), the measurement result B (no signal), and the measurement result C (with signal), the difference between the center frequency set by the control means 14 and the center frequency of the original segment ( 2/7 MHz).

  As described above, the determination result of the segment in which f1 shown in FIG. 5 is set as the center frequency cannot be received, and the difference between the center frequency set by the control unit 14 and the center frequency of the original segment is 2/7 MHz. It becomes. Then, the control unit 14 sets the center frequency of the next segment to be received in the tuner 12 without starting the demodulation operation in the OFDM demodulation unit 13 because the determination result cannot be received. The frequency set at this time is set to a frequency f3 obtained by adding 2/7 MHz to the center frequency f1 based on the difference (= 2/7 MHz) calculated together with the determination result.

  The demodulation operation in the OFDM demodulating unit 13 may be started simultaneously with the setting of the center frequency in the tuner 12. In this case, when receiving the determination that the reception is impossible from the determining unit 15, the control unit 14 determines that the OFDM demodulating unit 13 13 demodulation operation is stopped.

  Next, the determination result of the segment in which f1 is set as the center frequency is received, and the determination of the received power with f3 as the center frequency is performed in the same procedure as described above. The measurement result of each subchannel of the segment with f3 as the center frequency is a signal in any of the measurement result A, the measurement result B, and the measurement result C. Therefore, the determination result in the determination unit 15 can be received. The control unit 14 receives the determination that reception is possible from the determination unit 15, permits the demodulation process in the OFDM demodulation unit 13, and outputs demodulated data.

  In the conventional technique, the received power is measured in the segment unit (reception band 3/7 MHz width) to which the set center frequency belongs, and the presence / absence of a signal is determined. Therefore, when f1 shown in FIG. 5 is set as the center frequency, in reception power measurement for each subchannel, when reception power higher than a threshold set in advance in any one subchannel is detected, It may be determined that reception is possible. In that case, since the determination of reception failure is performed by the determination of the demodulation failure by the OFDM demodulator 13, the determination takes time.

  Further, in the conventional technique, when it is determined that the segment to which the set center frequency belongs cannot be received, the center frequency is shifted by 1/7 MHz to determine whether each segment can be received. For example, when it is determined whether or not reception is possible for a segment having a center frequency of f1, it is next determined whether or not reception is possible for a segment having a center frequency of f4. Thereafter, it is determined whether or not a segment having the receivable f3 as a center frequency can be received. For this reason, the measurement of the received power of each subchannel has been performed redundantly. However, according to the above configuration, the difference between the center frequency set by the control unit 14 and the center frequency of the original segment is calculated based on the measurement result of the received power for each subchannel, and the next frequency is calculated based on the difference. Since the center frequency of the segment for which the determination is made is determined, the measurement of the received power with overlapping subchannels can be reduced.

  According to the above configuration, the OFDM demodulating means 13 in the case where f1 can be selected as the center frequency and the time required for reception in the segment having f3 as the center frequency at which broadcast can actually be received can be shortened. In the channel selection operation, it is possible to shorten the time until the segment having the center frequency f3 that can be received by the broadcast is selected.

  Next, the configuration of a terrestrial digital audio broadcast receiver according to another embodiment will be described.

  FIG. 3 is a block diagram showing a configuration of the terrestrial digital audio broadcast receiver according to the present embodiment.

  The terrestrial digital audio broadcast receiver according to the present embodiment takes out a signal of a desired frequency from a broadcast wave received by the antenna 11, the control means 14, and the antenna with a bandwidth of 1 segment (3/7 MHz). A tuner (frequency selecting means) 12, an OFDM demodulating means 13 for demodulating the extracted frequency signal, and a reproduction section (not shown) for reproducing the demodulated data output from the OFDM demodulating means 13 for video, audio and data broadcasting, respectively. From the presentation means (not shown) for presenting the video, audio, and data broadcast reproduced by the reproduction unit to the user, the analog / digital conversion means 21 for converting the output signal of the tuner 12 into a digital signal, and the analog / digital conversion means 21 Fast discrete Fourier transform means 22 for converting the output digital signal into a frequency domain signal; Based on the reception level calculation means 23 for calculating the received power from the signal converted into the frequency domain signal by the conversion and the result measured by the reception level measurement means 23, the difference between the presence / absence of broadcasting and the channel selection frequency is determined. The determination means 15 is provided.

  Next, the operation of the terrestrial digital audio broadcast receiver according to this embodiment will be described. Control of the tuner 12 by the control means 14 is the same as that of the embodiment shown in FIG. The signal output of the 3/7 MHz bandwidth output from the tuner 12 is converted into a digital signal by the analog / digital conversion means 21. Next, it is converted into a signal in the frequency domain of 3/7 MHz bandwidth by the fast Fourier transform means 22. The reception level calculation means 23 divides the output data of the fast Fourier transform means 22 into 0 to 1/7 MHz, 1/7 MHz to 2/7 MHz, and 2/7 MHz to 3/7 MHz. calculate.

  With the above operation, as in the embodiment shown in FIG. 1, the segment with the bandwidth of 3/7 MHz is divided into three subchannels with the bandwidth of 1/7 MHz, and the received power of each subchannel is obtained.

  As in the embodiment shown in FIG. 1, the determination unit 15 determines whether or not there is a received signal for three signals having a bandwidth of 1/7 MHz. After determining the presence / absence of a received signal, determination of whether reception is possible and calculation of a difference between reception frequencies are performed based on the table shown in FIG.

  In this embodiment, the division into subchannels with a bandwidth of 1/7 MHz by the filter means 17 of the embodiment shown in FIG. 1 and the measurement of received power in the divided subchannels are replaced with a method by digital processing. Yes, the same effect as the embodiment shown in FIG. 1 can be obtained.

It is a block diagram which shows the structure of the terrestrial digital audio broadcasting receiver which concerns on this embodiment. (A) And (b) is a block diagram which shows the structure of a filter means. It is a block diagram which shows the structure of the terrestrial digital audio broadcasting receiver which concerns on other embodiment. It is a figure which shows the segment structure in terrestrial digital audio broadcasting. It is an example of the segment structure in terrestrial digital audio broadcasting. It is a figure which shows the content of determination by the determination means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Antenna 12 Tuner 13 OFDM demodulation means 14 Control means 15 Judgment means 16 Level measurement means 17 Filter means 21 Analog / digital conversion means 22 Fast Fourier transform means 23 Reception level calculation means

Claims (10)

In a terrestrial digital audio broadcasting receiver having an antenna capable of receiving terrestrial digital broadcasting waves,
Frequency selection means for extracting a signal in segment units from the terrestrial digital broadcast wave received by the antenna;
Dividing means for dividing the segment extracted by the frequency selecting means into a plurality of subchannels;
Level measuring means for measuring the reception level of each of the subchannels divided by the dividing means;
Measures whether or not the reception level of each subchannel measured by the level measurement means exceeds a threshold value, and receives the terrestrial digital broadcast wave in the segment when the reception levels of all the subchannels exceed the threshold value A terrestrial digital audio broadcast receiver comprising: a determination unit that determines that it is possible. Control means for setting a center frequency of the segment from which a signal is extracted;
2. The terrestrial digital audio broadcast receiver according to claim 1, wherein the frequency selection unit extracts a signal of the segment corresponding to the center frequency set by the control unit. When it is determined that the terrestrial digital broadcast wave cannot be received in the segment, the determination unit determines the segment based on the configuration of the subchannel in which the reception level exceeds the threshold and the subchannel in which the reception level does not exceed the threshold. Calculating means for calculating a difference between the center frequency of the segment and the center frequency of the segment capable of receiving a terrestrial digital broadcast wave,
The terrestrial digital audio broadcasting receiver according to claim 2, wherein the control means sets the center frequency of the segment from which a signal is next extracted based on the difference calculated by the calculating means.   The terrestrial digital audio broadcast receiver according to any one of claims 1 to 3, wherein the dividing unit divides the segment into three subchannels.   The terrestrial digital audio broadcasting receiver according to claim 4, wherein the bandwidth of the subchannel is 1/7 MHz. A tuning control method for a terrestrial digital audio broadcasting receiver having an antenna capable of receiving terrestrial digital broadcasting waves,
A frequency selection step of extracting a signal in segment units from the terrestrial digital broadcast wave received by the antenna;
A division step of dividing the segment extracted by the frequency selection step into a plurality of subchannels;
A level measuring step of measuring the reception level of each of the subchannels divided by the dividing step;
Measure whether or not the reception level of each of the subchannels measured by the level measurement step exceeds a threshold, and when the reception level of all the subchannels exceeds the threshold, receive a terrestrial digital broadcast wave in the segment A channel selection control method comprising: a determination step of determining that it is possible. A control step of setting a center frequency of the segment from which a signal is extracted;
The channel selection control method according to claim 6, wherein the frequency selection step includes a step of extracting a signal of the segment corresponding to the center frequency set by the control step. When it is determined that the terrestrial digital broadcast wave cannot be received in the segment, the determination step is based on the configuration of the subchannel in which the reception level exceeds the threshold and the configuration of the subchannel in which the reception level does not exceed the threshold. Calculating a difference between the center frequency of the segment and the center frequency of the segment capable of receiving a terrestrial digital broadcast wave;
8. The channel selection control method according to claim 7, wherein the control step includes a step of setting the center frequency of the segment from which a signal is next extracted based on the difference calculated by the calculation unit.   9. The channel selection control method according to claim 6, wherein the dividing step divides the segment into three subchannels.   The channel selection control method according to claim 9, wherein the bandwidth of the subchannel is 1/7 MHz.

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