JP5361481B2 - In-vehicle terrestrial digital broadcast receiver and channel search method thereof - Google Patents

Description

  The present invention relates to an in-vehicle terrestrial digital broadcast receiver and a channel search method thereof, and is particularly suitable for use in a receiver having a function of receiving an area-limited terrestrial digital broadcast.

  Japanese terrestrial digital broadcasting has a structure in which the frequency bandwidth of one channel is divided into 13 segments, of which 12 segments are allocated to high-definition broadcasting and 4 segments are allocated to standard-definition broadcasting. In addition, only one segment is allocated to broadcasting for mobile terminals such as mobile phones and in-vehicle devices having a small screen from the viewpoint of emphasizing mobility rather than image quality. Broadcasting for mobile terminals is referred to as “one-segment broadcasting” by omitting one segment. On the other hand, high-definition broadcasting that broadcasts one program using all 12 segments and standard-definition broadcasting that broadcasts up to three programs using 12 segments are called “full-segment broadcasting”.

  With regard to 1Seg broadcasting, there is currently a concept of “area limited 1Seg broadcasting” that broadcasts in a specific area, and several demonstration experiments have been conducted. Area-limited one-segment broadcasting is a system that can transmit radio waves without a broadcasting license if the maximum is about 100 m. For this reason, the expectation for area-limited one-segment broadcasting is increasing as one of new local media linked to a specific area. A technique related to a base station apparatus for realizing area-limited one-segment broadcasting has also been proposed (see, for example, Patent Document 1).

JP 2006-279376 A

  Area-limited one-segment broadcasting is very convenient to receive on mobile phones. This is because if the broadcast is received using a mobile phone at an event venue or the like where the area-limited one-segment broadcasting is performed, detailed information related to the event can be easily obtained. However, in-vehicle devices may be inconvenient with respect to receiving area-limited one-segment broadcasting. That is, it relates to a channel seek function and a channel scan function (in this specification, these functions are collectively referred to as a channel search function) provided in the in-vehicle device.

  The channel seek is a function for searching and receiving a frequency (channel) of a broadcasting station that can be received at the current location in response to pressing of the seek button. Each time the seek button is pressed, one broadcast station is searched, so that the desired broadcast station can be found by pressing the seek button several times. This function is useful when you don't know the frequency of the broadcast station.

  The channel scan is a function of searching for a plurality of broadcast stations that can be received at the current location in response to pressing of a scan button, and storing information on the found plurality of broadcast stations in a preset memory. Information on a plurality of broadcast stations stored in the preset memory is assigned to a plurality of preset buttons. Thereby, after the channel scan is executed, the broadcast station to be received can be easily switched by simply pressing a desired preset button. It is convenient to perform a channel scan again when the broadcast stations that can be received change as the vehicle moves.

  By the way, the in-vehicle device receives the one-segment broadcasting while moving at a relatively high speed. At that time, it may happen to pass through the reception area of the area-limited 1Seg broadcast, but if you perform a channel seek while passing through the reception area, the seek operation stops at the area-limited 1Seg broadcast station, and the area-limited 1Seg broadcast May be received. However, since the reception area of the area-limited one-segment broadcasting only happens to pass, the channel seek must be continued by pressing the seek button again. For this reason, there is a problem that the number of operations of the seek button performed until the desired broadcast station is found increases by one, and the search time is increased accordingly.

  In addition, if a channel scan is performed while accidentally passing the area-limited one-segment broadcasting reception area, the area-limited one-segment broadcasting station is also registered in the preset memory. However, since the reception area of the area-limited one-segment broadcasting only happens to pass, it is completely useless to register the broadcasting station in the preset memory. That is, there is a problem that a completely useless broadcasting station that cannot receive broadcasts outside the area-limited one-segment broadcasting reception area is registered in the preset memory with a limited number of registrations.

  The present invention has been made to solve such a problem. When a channel seek or channel scan is performed in an in-vehicle terrestrial digital broadcast receiver mounted on a moving vehicle, the area-limited one-segment broadcasting is performed. It is an object of the present invention to prevent inconvenience that broadcast stations are searched unnecessarily.

In order to solve the above-described problems, in the present invention, it is determined whether or not a broadcast station searched by channel search is a broadcast station for area-limited one-segment broadcasting based on information included in the broadcast wave. When it is determined that the broadcast station is a broadcast station, the search result of the broadcast station is invalidated.

  According to the present invention configured as described above, even if a broadcast station is searched by channel seek or channel scan, if it is determined that the broadcast station is an area-limited one-segment broadcast, the search result is invalidated. The next broadcasting station will continue to be searched. As a result, when a channel seek or channel scan is performed on an in-vehicle terrestrial digital broadcast receiver mounted on a moving vehicle, the seek operation stops when a broadcast station for area-limited one-segment broadcasting is searched. It is possible to prevent inconvenience that the information of the broadcasting station of the area-limited one-segment broadcasting is unnecessarily registered in the preset memory.

It is a figure which shows the structural example of the vehicle-mounted digital terrestrial broadcasting receiver by 1st Embodiment. It is a flowchart which shows the operation example at the time of the channel seek of the vehicle-mounted digital terrestrial broadcasting receiver by 1st Embodiment. It is a flowchart which shows the operation example at the time of the channel scan of the vehicle-mounted digital terrestrial broadcasting receiver by 1st Embodiment. It is a figure which shows the structural example of the vehicle-mounted digital terrestrial broadcasting receiver by 2nd Embodiment. It is a flowchart which shows the operation example at the time of the channel seek of the vehicle-mounted digital terrestrial broadcasting receiver by 2nd Embodiment. It is a flowchart which shows the operation example at the time of the channel scan of the vehicle-mounted digital terrestrial broadcasting receiver by 2nd Embodiment. It is a figure which shows the structural example of the vehicle-mounted digital terrestrial broadcasting receiver by 3rd Embodiment.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of an in-vehicle terrestrial digital broadcast receiver according to the first embodiment. In FIG. 1, an antenna 1 receives radio waves of terrestrial digital broadcasting. The tuner 2 selectively extracts a broadcast wave signal having a reception frequency that matches a desired channel from the terrestrial digital broadcast radio wave received by the antenna 1 and outputs the broadcast wave signal.

  The tuner 2 searches for a currently receivable channel (broadcast station) when execution of channel search such as channel seek or channel scan is instructed by operation of an operation unit (not shown). That is, the tuner 2 searches for a reception frequency that can be synchronized with OFDM (Orthogonal Frequency-Division Multiplexing) while changing the setting of the reception frequency by a predetermined amount. Then, a broadcast wave signal having a reception frequency synchronized with OFDM is extracted from a radio wave of digital terrestrial broadcasting and output. Thus, the tuner 2 corresponds to the broadcast station searching unit and the broadcast wave receiving unit of the present invention.

  The OFDM demodulator 3 performs OFDM demodulation on the broadcast wave signal received by the tuner 2 to obtain a transport stream (hereinafter referred to as TS). If the OFDM demodulator 3 succeeds in establishing the OFDM synchronization during the demodulation process, the OFDM demodulator 3 notifies the TMCC decoder 4 and the controller 10 of this fact. In response to this, the control unit 10 notifies the tuner 2 that synchronization has been achieved. The tuner 2 performs a channel search while checking the presence / absence of notification from the control unit 10.

  The TMCC decoding unit 4 receives a notification of synchronization establishment from the OFDM demodulating unit 3 and TMCC decodes the broadcast wave signal received by the tuner 2 to obtain TMCC (Transmission and Multiplexing Configuration and Control) information which is transmission control information. Based on the TMCC information decoded by the TMCC decoding unit 4, the error correction unit 5 corrects errors generated in the transmission path for the TS demodulated by the OFDM demodulation unit 3.

  Here, the TMCC information includes information such as system identification information, a partial reception flag, an A layer transmission parameter, a B layer transmission parameter, and a C layer transmission parameter. The system identification information is information indicating whether the broadcast wave content is television or sound. The partial reception flag is information indicating whether there is partial reception of a segment. Partial reception means reception of a broadcast wave by only a part of 13 segments obtained by dividing the frequency bandwidth of one channel, that is, reception of one-segment broadcasting. When the broadcast format is compatible with only one segment or both full segment and one segment, the partial reception flag is “present”. On the other hand, if the broadcast format supports only full segment, the partial reception flag is “none”.

  The A layer transmission parameter is information indicating various transmission parameters related to the one-segment broadcasting. The B layer transmission parameter is information indicating various transmission parameters related to the high-definition broadcasting. The C layer transmission parameter is information indicating various transmission parameters related to the standard definition broadcast. When the broadcast format supports only one segment, there is no B layer transmission parameter or C layer transmission parameter.

  The demultiplexer unit 6 separates the multiplexed TS to obtain a video stream, an audio stream, and a data stream. Then, the demultiplexer unit 6 outputs the audio stream to the audio decoder unit 7, outputs the video stream to the video decoder unit 8, and outputs the data stream to the data decoder unit 9. Here, the data stream includes information such as NIT (Network Information Table) and EIT (Event Information Table). The NIT includes network identification information, transmission mode, guard interval value, and the like. The EIT includes information about the program such as the program name, broadcast date and time, and description of the contents.

  The audio decoder unit 7 decodes the input audio stream and outputs it as an audio signal. The video decoder unit 8 decodes the input video stream and outputs it as a video signal. The data decoder unit 9 decodes the input data stream and outputs the decoded data stream to the control unit 10 as control data. The control data output to the control unit 10 includes the NIT and EIT described above.

  The control unit 10 determines a channel that the tuner 2 receives when a channel setting control signal is input by operating an operation unit (not shown), and sets a reception frequency that matches the channel in the tuner 2.

  In addition, when a control signal indicating a channel seek execution instruction is input by an operation of an operation unit (not shown), the control unit 10 searches for another channel that can be currently received and switches the reception frequency of the tuner 2. Is set by changing a certain amount from the current reception frequency. At this time, if a notification of establishment of synchronization is not sent from the OFDM demodulator 3, the reception frequency of the tuner 2 is further changed by a certain amount and set. The control unit 10 repeats this operation until a notification of establishment of synchronization is sent from the OFDM demodulator 3, and stops the channel seek operation when the notification is sent.

  In addition, when a control signal indicating a channel scan execution instruction is input by an operation of an operation unit (not shown), the control unit 10 generates a list of channels that can be currently received in order to generate a receivable frequency of terrestrial digital broadcasting The reception frequency of tuner 2 is set to the lowest frequency in the band. At this time, if a notification of establishment of synchronization is not sent from the OFDM demodulator 3, the reception frequency of the tuner 2 is changed and set by a certain amount. On the other hand, when a notification of synchronization establishment is sent from the OFDM demodulator 3, the controller 10 stores the received frequency (channel) at that time in the preset memory 11 and registers it. After performing such a registration operation for the number of channels prepared in the preset memory 11 in advance, the control unit 10 stops the channel scan operation.

Regarding the channel seek or channel scan as described above, the control unit 10 has a function specific to the present embodiment. The configuration for realizing the function is the broadcast station determination unit 10a and the search control unit 10b. The broadcast station determination unit 10a determines that the searched channel (broadcast station) is an area-limited one-segment signal based on information included in the broadcast wave signal received by the tuner 2 in the channel searched during channel seek or channel scan. It is determined whether or not it is a broadcasting station .

  Specifically, the broadcast station determination unit 10a determines that a broadcast station searched by channel seek or channel scan based on network identification information included in the broadcast wave signal received by the tuner 2 is an area-limited one-segment broadcast station. It is determined whether or not. In the area limited one-segment broadcasting, the value of the network identification information is “0x7E8E”. Therefore, the broadcast station determination unit 10a determines whether the searched broadcast station is a broadcast station for area-limited one-segment broadcasting depending on whether the value of the network identification information is “0x7E8E”.

  If the broadcast station determination unit 10a determines that the search control unit 10b is a broadcast station for area-limited one-segment broadcasting, the search control unit 10b invalidates the search result of the broadcast station. That is, if channel seek is being performed, the retrieved reception frequency is invalidated, and the reception frequency of the tuner 2 is further changed by a certain amount and set. Further, if channel scanning is being performed, the searched reception frequency is invalidated, and the reception frequency at that time is not registered in the preset memory 11, and the reception frequency of the tuner 2 is further changed by a certain amount. To set.

  On the other hand, if the broadcast station determination unit 10a determines that the broadcast station is not an area-limited one-segment broadcast station, the search result of the broadcast station is validated. That is, if channel seek is being performed, the retrieved reception frequency is validated and the channel seek operation is stopped. If the channel scan is being performed, the retrieved reception frequency is registered in the preset memory 11, and the reception frequency of the tuner 2 is further changed by a certain amount and set.

  Next, an operation example of the in-vehicle digital terrestrial broadcasting receiver according to the first embodiment configured as described above, that is, a processing procedure of the channel search method according to the first embodiment will be described. FIG. 2 is a flowchart showing an operation example during channel seek of the in-vehicle digital terrestrial broadcast receiver according to the first embodiment. The flowchart shown in FIG. 2 starts when channel seek execution is instructed by operation of the operation unit.

  In FIG. 2, first, the control unit 10 sets an adjacent frequency that is changed by a certain amount from the current reception frequency and issues a tuning instruction to the tuner 2 (step S <b> 1). In response to this instruction, the tuner 2 tunes the reception frequency to the adjacent frequency (step S2). Next, the OFDM demodulator 3 estimates the transmission mode and the guard interval according to the OFDM demodulation procedure (step S3). Then, the OFDM demodulator 3 performs FFT (Fast Fourier Transform) processing according to the estimated transmission mode and guard interval, and tries OFDM synchronization (step S4).

  Here, the OFDM demodulator 3 determines whether synchronization has been established (step S5). If synchronization cannot be established, the process jumps to step S11. On the other hand, when synchronization is established, the TMCC decoding unit 4 decodes the broadcast wave signal received by the tuner 2 to obtain TMCC information (step S6). Then, the error correction unit 5 performs error correction on the TS output from the OFDM demodulating unit 3 based on the TMCC information, and the demultiplexer unit 6 separates the TS to generate a video stream, an audio stream, and a data stream. Obtain (step S7).

  Next, the data decoder unit 9 decodes the data stream input from the demultiplexer unit 6 and generates control data including NIT and EIT. The control unit 10 inputs control data including NIT (step S8). Then, the broadcast station determination unit 10a of the control unit 10 determines whether or not the value of the network identification information included in the NIT is “0x7E8E” (step S9).

  If the value of the network identification information is not “0x7E8E”, it means that the broadcast station having the frequency tuned in step S2 is not an area-limited one-segment broadcast station, so that the search control unit 10b stops the channel seek operation. Control. Thereby, the tuner 2 adopts the reception frequency tuned in step S2 as it is, and receives the broadcast wave signal of the reception frequency (step S10). This completes the channel seek operation.

  On the other hand, if the value of the network identification information is “0x7E8E”, it means that the broadcast station having the frequency tuned in step S2 is a broadcast station for area-limited one-segment broadcasting, so the search control unit 10b is tuned in step S2. Disable reception frequency. In this case, the search control unit 10b determines whether there is an adjacent frequency to be set next in the receivable frequency band of terrestrial digital broadcasting (step S11). The frequency is further changed by a certain amount and set (step S12). Thereafter, the process returns to the process of step S2. If there is no adjacent frequency, the channel seek operation is terminated.

  FIG. 3 is a flowchart showing an operation example at the time of channel scanning of the in-vehicle digital terrestrial broadcasting receiver according to the first embodiment. The flowchart shown in FIG. 3 is started when execution of a channel scan is instructed by operation of the operation unit.

  In FIG. 3, first, the control unit 10 sets the reception frequency of the tuner 2 to the lowest first frequency (13 ch) in the receivable frequency band of digital terrestrial broadcasting, and issues a tuning instruction to the tuner 2 (step) S21). In response to this instruction, the tuner 2 tunes the reception frequency to the initial frequency (step S22). Next, the OFDM demodulator 3 estimates the transmission mode and the guard interval according to the OFDM demodulation procedure (step S23). Then, the OFDM demodulator 3 performs FFT processing according to the estimated transmission mode and guard interval, and tries OFDM synchronization (step S24).

  Here, the OFDM demodulator 3 determines whether synchronization has been established (step S25). If synchronization cannot be established, the process jumps to step S31. On the other hand, when synchronization is established, the TMCC decoding unit 4 decodes the broadcast wave signal received by the tuner 2 to obtain TMCC information (step S26). Then, the error correction unit 5 performs error correction on the TS output from the OFDM demodulating unit 3 based on the TMCC information, and the demultiplexer unit 6 separates the TS to generate a video stream, an audio stream, and a data stream. Obtain (step S27).

  Next, the data decoder unit 9 decodes the data stream input from the demultiplexer unit 6 and generates control data including NIT and EIT. The control unit 10 inputs control data including NIT (step S28). Then, the broadcast station determination unit 10a of the control unit 10 determines whether or not the value of the network identification information included in the NIT is “0x7E8E” (step S29).

  If the value of the network identification information is not “0x7E8E”, it means that the broadcast station having the frequency tuned in step S22 is not an area-limited one-segment broadcast station, and therefore the search control unit 10b receives the reception frequency tuned in step S2. Is registered in the preset memory 11 (step S30). At this time, in addition to the reception frequency, a modulation parameter used for demodulation by the OFDM demodulator 3 may be generated and registered, or necessary data may be generated and registered in the electronic program guide from the EIT. good.

  Thereafter, the search control unit 10b determines whether or not the currently searched frequency is the highest frequency (62ch) (step S31), and if not, changes the reception frequency of the tuner 2 by a certain amount. Set (step S32). Thereafter, the process returns to the process of step S22. If it is the highest frequency, the channel scan operation is terminated.

  On the other hand, if it is determined in step S29 that the value of the network identification information is “0x7E8E”, it means that the broadcast station having the frequency tuned in step S22 is a broadcast station for area-limited one-segment broadcasting. The process jumps to step S31 without registering in the preset memory 11 by.

  As described above in detail, in the first embodiment, whether or not the value of the network identification information included in the broadcast wave signal of the broadcast station searched by channel search such as channel seek or channel scan is “0x7E8E”. Based on the above, it is determined whether or not the searched broadcast station is a broadcast station for area limited one-segment broadcasting. I try to make it invalid.

  According to the first embodiment configured as described above, even if a broadcasting station is searched by channel seek or channel scanning, if it is determined that the broadcasting station is an area-limited one-segment broadcasting station, the search result is invalid. As a result, the next broadcasting station is continuously searched. As a result, when a channel seek or channel scan is performed on an in-vehicle terrestrial digital broadcast receiver mounted on a moving vehicle, the seek operation stops when a broadcast station for area-limited one-segment broadcasting is searched. It is possible to prevent inconvenience that the information on the broadcasting station of the area-limited one-segment broadcasting is unnecessarily registered in the preset memory 11.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a diagram illustrating a configuration example of an in-vehicle terrestrial digital broadcast receiver according to the second embodiment. In FIG. 4, those given the same reference numerals as those shown in FIG. 1 have the same functions, and therefore redundant description is omitted here. In the second embodiment, instead of the broadcast station determination unit 10a, a broadcast station determination unit 10a ′ having a different function from this is provided.

  In addition to determining whether the value of the network identification information included in the NIT is “0x7E8E”, the broadcasting station determination unit 10a ′ performs the following determination. That is, based on the TMCC information decoded by the TMCC decoding unit 4, the broadcast station determination unit 10a ′ determines whether the broadcast format of the broadcast station tuned by channel seek or channel scan is a one-seg only broadcast format. . When the broadcast format is only one seg, it is determined that the tuned broadcast station is a broadcast station for area-limited one seg broadcasting.

  Area-limited one-segment broadcasting does not require a license to transmit radio waves, whereas ordinary one-segment broadcasting and full-segment broadcasting require a license. Therefore, when the broadcast format is compatible with only one seg, it is either an area-limited one seg broadcast by an unlicensed company, or a general one seg broadcast or an area-limited one seg broadcast by a licensed company. However, it is considered unlikely that an operator who has a full-segment broadcasting license transmits broadcast waves in a broadcasting format that supports only one-segment broadcasting. Then, if the broadcast format is only compatible with one seg, it can be considered that there is a high possibility that it is an area-limited one seg broadcast by an unlicensed company. Therefore, in the second embodiment, when the broadcast format is a format corresponding to only one segment, it is determined that the tuned broadcast station is a broadcast station for area-limited one-segment broadcasting.

  Next, an operation example of the in-vehicle terrestrial digital broadcast receiver according to the second embodiment configured as described above, that is, a processing procedure of the channel search method according to the second embodiment will be described. FIG. 5 is a flowchart showing an operation example during channel seek of the in-vehicle digital terrestrial broadcasting receiver according to the second embodiment. The flowchart shown in FIG. 5 is started when execution of channel seek is instructed by operation of the operation unit.

  In FIG. 5, the processes given the same numbers as the step numbers shown in FIG. 2 are the same processes, and therefore, the duplicate description is omitted here. In the second embodiment, the processes of steps S13 and S14 are inserted between the process of step S6 and the process of step S7.

  In FIG. 5, when the TMCC information is decoded by the TMCC decoding unit 4 (step S6), the broadcast station determination unit 10a ′ determines whether the broadcast format is a format corresponding to only one seg based on the TMCC information. Is determined (step S13). Specifically, when the system identification information included in the TMCC information indicates “TV”, the partial reception flag indicates “partial reception is present”, and there is no B layer transmission parameter (or a C layer transmission parameter), The broadcast station determination unit 10a ′ determines that the broadcast format is a format corresponding to only one segment.

If the broadcast format is determined to be in a format corresponding only to the one-segment, since it is an area limited one-segment broadcasting using unlicensed operator, the processing jumps to step S11. On the other hand, if it is determined that the broadcast format is not a format compatible with only one segment, the broadcast station determination unit 10a ′ determines whether the broadcast format is a format compatible with only full segment based on the TMCC information ( Step S14). Specifically, when the system identification information included in the TMCC information indicates “TV” and the partial reception flag indicates “no partial reception”, the broadcast station determination unit 10a ′ supports only the full segment broadcasting format. Is determined to be in the format.

  Here, when it is determined that the broadcast format is a format that supports only full segment, there is no possibility of area-limited one-segment broadcast, so the process jumps to step S10. On the other hand, if it is determined that the broadcast format is not a format that supports only full segment, the broadcast wave being received may or may not be an area-limited one-segment broadcast, so the process proceeds to step S7, and subsequent step S8. , S9 performs the same determination as in the first embodiment.

  FIG. 6 is a flowchart showing an operation example at the time of channel scanning of the in-vehicle digital terrestrial broadcasting receiver according to the second embodiment. The flowchart shown in FIG. 6 is started when execution of channel scan is instructed by operation of the operation unit. In FIG. 6, the processes given the same numbers as the step numbers shown in FIG. 3 are the same processes, and therefore, a duplicate description is omitted here. In the second embodiment, the processes of steps S33 and S34 are inserted between the process of step S26 and the process of step S27.

In FIG. 6, when the TMCC information is decoded by the TMCC decoding unit 4 (step S26), the broadcast station determination unit 10a ′ determines whether the broadcast format is a format corresponding to only one seg based on the TMCC information. Is determined (step S33). If the broadcast format is determined to be in a format corresponding only to the one-segment, since it is an area limited one-segment broadcasting using unlicensed operator, the processing jumps to step S31.

  On the other hand, if it is determined that the broadcast format is not a format compatible with only one segment, the broadcast station determination unit 10a ′ determines whether the broadcast format is a format compatible with only full segment based on the TMCC information ( Step S34). Here, if it is determined that the broadcast format is a format that supports only full seg, it cannot be an area-limited one seg broadcast, so the process jumps to step S30. On the other hand, if it is determined that the broadcast format is not a format corresponding to only full segment, the process proceeds to step S27, and the same determination as in the first embodiment is performed in subsequent steps S28 and S29.

  As described above in detail, in the second embodiment, the searched broadcast station is an area based on the TMCC information included in the broadcast wave signal of the broadcast station searched by channel search such as channel seek or channel scan. It is determined whether or not the broadcast station is a limited one-segment broadcast. If it is determined that the broadcast station is an area-limited one-segment broadcast, the search result of the broadcast station is invalidated. According to the second embodiment configured as described above, it is possible to determine to some extent whether or not the broadcast station is an area-limited one-segment broadcasting at an early stage before decoding the NIT, and the time required for the determination can be shortened. can do.

  In the second embodiment, when the broadcast format is not only one-segment or full-segment, it is determined whether or not the broadcast station is an area-limited one-segment broadcast by the same method as the first embodiment. ing. Thereby, even if it is a case where it cannot discriminate | determine whether it is area limited one-segment broadcasting only by TMCC information, it can be determined reliably whether it is area limited one-segment broadcasting from the network identification information of NIT.

(Third embodiment)
Next, a third embodiment according to the present invention will be described with reference to the drawings. FIG. 7 is a diagram illustrating a configuration example of an in-vehicle terrestrial digital broadcast receiver according to the third embodiment. In FIG. 7, those given the same reference numerals as those shown in FIG. 1 have the same functions, and therefore redundant description is omitted here. In the third embodiment, a stop determination unit 12 and a mode information storage unit 13 are provided in addition to the configuration shown in FIG. Further, instead of the search control unit 10b shown in FIG. 1, a search control unit 10b ′ having a different function from this is provided.

  The stop determination unit 12 receives a notification from the broadcast station determination unit 10a when the broadcast station determination unit 10a determines that the broadcast station tuned by the channel search is an area-limited one-segment broadcast station. Then, it is determined whether or not the vehicle is stopped. The stop determination unit 12 is connected to the in-vehicle LAN 20 and determines whether or not the vehicle is stopped based on a signal transmitted through the in-vehicle LAN 20. For example, it is possible to determine whether or not the vehicle is stopped based on a vehicle speed signal sent from the in-vehicle LAN 20. It is also possible to determine whether or not the vehicle is stopped based on a signal indicating whether the side brake is applied or a signal indicating whether the accessory key is on.

  The search control unit 10b ′ is a tuned broadcast station when the broadcast station determination unit 10a determines that the broadcast station is an area-limited one-segment broadcast and the stop determination unit 12 determines that the vehicle is not stopped. Disable search results for. That is, the tuned broadcasting station is an area-limited one-segment broadcasting station, and the fact that the vehicle is not stopped is considered to be simply passing through the area-limited one-segment broadcasting reception area. Broadcast station search results are invalid.

  On the other hand, when the broadcast station determination unit 10a determines that the broadcast station is an area-limited one-segment broadcast and the stop determination unit 12 determines that the vehicle is stopped, or the broadcast station determination unit 10a determines that the area-limited one-segment broadcast station When it is determined that the broadcast station is not a broadcast station, the search control unit 10b ′ validates the search result of the tuned broadcast station. In other words, even if the tuned broadcasting station is an area-limited one-segment broadcasting station, the fact that the vehicle is stopped is considered to be a manifestation of the user's desire to view the area-limited one-segment broadcasting. Search results for broadcast stations are valid.

  In this way, when the user wants to view the area-limited one-segment broadcasting, it is possible to prevent the broadcasting station tuned by channel seeking or channel scanning from being invalidated.

  Further, the mode information storage unit 13 stores mode information set as to whether or not to perform the operations of the broadcast station determination unit 10a and the search control unit 10b '. The mode information for the mode information storage unit 13 is set in advance by the user operating an operation unit (not shown). Here, when it is set by the mode information that the operations of the broadcast station determination unit 10a and the search control unit 10b ′ are not performed, the control unit 10 searches for a broadcast station tuned by channel seek or channel scan. Always enable results.

  In addition, you may apply control of the control part 10 based on mode information to 1st Embodiment or 2nd Embodiment. Moreover, you may apply control of the control part 10 based on the determination result by the stop determination part 12 to 1st Embodiment or 2nd Embodiment.

  In the first to third embodiments, in the channel scan operation, when the value of the network identification information is “0x7E8E” (when the area-limited one-segment broadcast is received), the reception frequency and the modulation parameter The example in which the data necessary for the electronic program guide is not registered in the preset memory 11 has been described, but the present invention is not limited to this. For example, if it is determined that the broadcast format is a format corresponding to both one-segment and full-segment based on TMCC information, and the value of the network identification information is determined to be “0x7E8E”, it is used for full-segment broadcasting. The reception frequency, the modulation parameter, etc. may be registered in the preset memory 11. If it is determined that the broadcast format is compatible with both 1Seg and Full Seg based on TMCC information, and the value of the network identification information is not “0x7E8E”, it is for 1Seg Broadcast and Full Seg. A reception frequency, a modulation parameter, and the like are registered in the preset memory 11 for broadcasting.

  In addition, each of the first to third embodiments is merely an example of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. It will not be. In other words, the present invention can be implemented in various forms without departing from the spirit or main features thereof.

2 Tuner 4 TMCC decoding unit 10 Control unit 10a, 10a ′ Broadcast station determination unit 10b, 10b ′ Search control unit 11 Preset memory 12 Stop determination unit 13 Mode information storage unit

Claims (6)

An in-vehicle terrestrial digital broadcast receiver mounted on a vehicle,
In response to a channel search instruction operation, a broadcast station search unit that searches for broadcast stations that can be received at the current location,
A broadcast wave receiving unit that receives broadcast waves of the broadcast station searched by the broadcast station search unit;
A broadcast station determination unit that determines whether or not the broadcast station searched by the broadcast station search unit is a broadcast station for area-limited one-segment broadcasting based on information included in the broadcast wave received by the broadcast wave reception unit;
When the broadcast station determination unit determines that the broadcast station is the area limited one-segment broadcast, the search result of the broadcast station is invalidated. When the broadcast station determination unit determines that the broadcast station is not the area limited one-segment broadcast, the broadcast An in-vehicle terrestrial digital broadcast receiver comprising: a search control unit that controls a search result of a broadcasting station to be valid. The broadcast station determination unit determines whether the broadcast station searched by the broadcast station search unit is a broadcast station for the area-limited one-segment broadcasting based on network identification information included in the broadcast wave received by the broadcast wave reception unit. The in-vehicle terrestrial digital broadcast receiver according to claim 1, wherein the terrestrial digital broadcast receiver is mounted. The broadcast station determination unit determines whether the broadcast format of the broadcast station searched by the broadcast station search unit is a one-segment broadcast format based on transmission control information included in the broadcast wave received by the broadcast wave reception unit. When the broadcast format is only one seg, it is determined that the broadcast station searched by the broadcast station search unit is a broadcast station of the area limited one seg broadcast, and the broadcast format is not only one seg. Further, based on the network identification information included in the broadcast wave received by the broadcast wave receiver, it is further determined whether or not the broadcast station searched by the broadcast station search unit is a broadcast station of the area limited one-segment broadcasting The in-vehicle terrestrial digital broadcast receiver according to claim 2. When it is determined by the broadcast station determination unit that it is a broadcast station of the area-limited one-segment broadcasting, the vehicle further includes a stop determination unit that determines whether the vehicle is stopped,
The search control unit invalidates the search result of the broadcast station searched by the broadcast station search unit when the stop determination unit determines that the vehicle is not stopped, while the stop determination unit When the vehicle is determined to be stopped or the broadcast station determination unit determines that the vehicle is not a broadcast station for the area-limited one-segment broadcasting, the search result of the broadcast station searched by the broadcast station search unit is valid. The in-vehicle terrestrial digital broadcast receiver according to claim 1, wherein A mode information storage unit for storing mode information set as to whether or not to perform the operation of the broadcast station determination unit and the search control unit;
When it is set by the mode information that the operation of the broadcast station determination unit and the search control unit is not performed, the search control unit displays the search result of the broadcast station searched by the broadcast station search unit. 2. The in-vehicle terrestrial digital broadcast receiver according to claim 1, which is always enabled. A channel search method for an in-vehicle terrestrial digital broadcast receiver mounted on a vehicle,
A first step of searching for a receivable broadcasting station at the current location in response to a channel search instruction operation;
A second step of receiving the broadcast wave of the broadcasting station searched in the first step;
A third step of determining whether or not the broadcast station searched in the first step is a broadcast station for area-limited one-segment broadcasting based on information included in the broadcast wave received in the second step;
If it is determined in the third step that the broadcast station is the area limited one-segment broadcast, the search result of the broadcast station is invalidated. If it is determined that the broadcast station is not the area limited one-segment broadcast, A channel search method for an on-vehicle digital terrestrial broadcast receiver, comprising: a fourth step of validating a search result of a broadcast station.