JP4578413B2 - TMC channel selection method and RDS receiver in RDS broadcasting - Google Patents

Description

  The present invention relates to a TMC channel selection method for automatically detecting a TMC broadcast providing a desired TMC service in an RDS receiver compatible with the TMC service, and an RDS receiver compatible with the TMC service.

In recent years, traffic information broadcasting that provides traffic information for moving bodies such as automobiles is being used. As one of such traffic information broadcasts, there is TMC (Traffic Message Channel) using RDS (Radio Data System) broadcast. RDS broadcasting is a system proposed and put into practical use by the European Broadcasting Union. In RDS, digital data (RDS data) is superimposed on an analog FM broadcast signal. In TMC, RDS data includes identification information of a traffic information service and data of the traffic information service itself. In the following description, data relating to these traffic information services is referred to as TMC data. As a receiving apparatus corresponding to such TMC, there is one described in Patent Document 1.
JP-A-8-204593

  TMC data is traffic information data organized for each region and road, and is received by a TMC-compatible receiving device, then interpreted within the receiving device, and in a desired format (for example, voice, text message) Or as a car navigation icon displayed on the screen).

  In RDS broadcasting, there are many cases where broadcasts with the same content are broadcast at different frequencies for each region. Therefore, the receiving device has a TMC channel selection function of detecting a TMC broadcast that provides a desired TMC service by searching for a frequency.

  In a conventional RDS receiver, TMC channel selection is performed in the following procedure. FIG. 1 is a flowchart showing TMC channel selection processing in a conventional RDS receiver. This routine is executed when the user of the receiving apparatus performs a predetermined operation. When this routine is executed, step S101 is first executed.

  In step S101, scanning is performed using a PLL or the like, and a program having an arbitrary frequency is received. Next, the process proceeds to step S102.

  In step S102, the reception state of the signal is checked, and it is determined whether or not a sufficient signal level is obtained. When it is determined that a sufficient signal level is obtained (S102: YES), the process proceeds to step S103. On the other hand, when it is determined that a sufficient signal level is not obtained (S102: NO), the process returns to step S101, and reception at another frequency is performed.

  In step S103, counting of the internal timer of the receiving apparatus is started. Next, the process proceeds to step S104.

  In step S104, it is confirmed whether or not RDS data is included in the broadcast of the currently received frequency. If it is confirmed that the RDS data is included (step S104: YES), the process proceeds to step S106. On the other hand, if the RDS data cannot be detected (S104: NO), the process proceeds to step S105.

  In step S105, it is confirmed whether the count value of the timer set in step S103 has reached a predetermined value. If the count value has reached the predetermined value (S105: YES), it is determined that this broadcast does not include RDS data, and the process returns to step S101 to receive at another frequency. On the other hand, if the count value does not reach the predetermined value (S105: NO), it is determined that there is still a possibility that RDS data cannot be detected, and the process returns to step S104. That is, the loop of steps S103 to S105 is a branching step in which if the RDS cannot be detected within a predetermined time, the process proceeds to step S106, and if it cannot be detected, the process returns to step S101 to test another frequency.

  In step S106, counting of the internal timer of the receiving apparatus is started. Next, the process proceeds to step S107.

  In step S107, it is determined whether or not RDS data has been acquired. If the RDS data has been acquired (S107: YES), the process proceeds to step S108. On the other hand, if acquisition of RDS data has failed (S107: NO), the process proceeds to step S110.

  In step S108, it is checked whether all RDS data related to TMC has been acquired. If all the RDS data has been acquired (S108: YES), the process proceeds to step S109. On the other hand, if all the RDS data has not been acquired yet (S109: NO), the process proceeds to step S110.

  In step S110, it is confirmed whether the count value of the timer set in step S106 has reached a predetermined value. If the count value has reached a predetermined value (S110: YES), it is determined that acquisition of RDS data has failed for this broadcast, and the process returns to step S101 to receive at another frequency. On the other hand, if the count value has not reached the predetermined value (S106: NO), it is simply determined that RDS data is being acquired, and the process returns to step S107. In other words, the loop of steps S107, 108, and 110 proceeds to step S109 if acquisition of RDS data cannot be completed within a predetermined time, and returns to step S101 if it cannot be detected, and a branching step for testing other frequencies. It is.

  In step S109, using the identification information included in the TMC data, it is determined whether or not the TMC broadcast provides a desired TMC service. More specifically, a table in which the TMC service name can be determined from the identification information included in the TMC data is built in the memory of the receiving apparatus, and determination is performed using this table as a filter in step S109. . If it is determined that the currently received TMC broadcast provides the desired TMC service (S109: YES), this routine is terminated. On the other hand, if it is determined that the currently received TMC broadcast does not provide the desired TMC service (S109: NO), the process returns to step S101, and a test for another frequency is performed.

  As described above, in the conventional configuration, the TMC data is checked until it is confirmed that the TMC broadcast providing the desired TMC service has been received.

  However, the time required to read all TMC data in a program is as long as several tens of seconds. With the conventional method, there is a possibility that it may take several minutes at a long time until a desired TMC program can be received. It was.

  In view of the above problems, the present invention provides a TMC channel selection method that can receive a TMC broadcast that provides a desired TMC service in a shorter time, and an RDS receiver that receives the TMC broadcast based on the channel selection method. The purpose is to do.

  To achieve the above object, the TMC channel selection processing of the present invention includes a scanning step for detecting a receivable TMC broadcast, and a PI extraction for extracting a PI code from RDS data of the TMC broadcast detected in the scanning step. A first PI determining step for determining whether the TMC broadcast corresponding to the extracted PI code provides a desired TMC service; and a TMC service for which the TMC broadcast corresponding to the extracted PI code is desired Corresponding to the extracted PI code and a first TMC information acquisition step of extracting TMC information from the RDS data of the TMC broadcast when it is found in the first PI determination step When it is determined in the first PI determination step that the TMC broadcast does not provide the desired TMC service, the scanning step is performed. The re-execute to detect the broadcast other TMC, it has a first rescan instruction step.

  That is, in the configuration of the present invention, the PI code is detected once, and referring to the PI code, it is confirmed whether a TMC broadcast providing a desired TMC service is received. The PI code is transmitted more frequently than the TMC data, and can be acquired in a time much shorter than the time required for receiving the TMC data. Therefore, according to the configuration of the present invention, the time from when the reception of the TMC broadcast is started until the determination of whether or not the TMC broadcast providing the desired TMC service is received is shortened. Therefore, according to the present invention, a desired TMC service can be performed in a shorter time.

  The first PI determination step refers to a table in which a PI code and a TMC service provided by the TMC broadcast having the PI code are associated with each other, and a TMC broadcast corresponding to the extracted PI code is desired. It is good also as a structure which discriminate | determines whether the TMC service is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 is a block diagram of the RDS receiver of this embodiment.

  The RDS receiver 1 according to the present embodiment is mainly mounted on an automobile and has a function as an in-vehicle radio that extracts an audio signal from an RDS broadcast signal output as a radio wave and outputs it from a speaker. is there.

  The RDS receiver 1 according to the present embodiment selectively includes an antenna 11 for receiving broadcast radio waves, a tuner 12 that extracts and outputs audio signals and digital data from received signals, and an audio signal output from the tuner 12. The mute circuit 13 for muting the sound, the amplifier circuit 14 for amplifying the sound signal output from the mute circuit 13 to a predetermined level when the mute circuit 13 does not mute, and the sound output from the amplifier circuit 14 A speaker 15 that outputs a signal as sound and a PLL circuit 19 that sets the frequency of a radio wave received by the tuner 12 by performing phase synchronization of the received signal.

  In other words, the PLL circuit 13 controls the tuner 12 so that a signal having a desired frequency is extracted from the radio signal received by the antenna 11, and the resulting audio signal passes through the mute circuit 13 and the amplifier circuit 14. Thus, the sound is output from the speaker 15. The mute circuit 13 is a circuit for performing mute when the user of the RDS receiver 1 desires to mute the sound temporarily, or when performing frequency tracking described later. The RDS receiver 1 according to the present embodiment further includes a microcomputer 18, and the mute circuit 13, the amplifier circuit 14, and the PLL circuit 19 are controlled by the microcomputer 18.

  Furthermore, the RDS receiver 1 of this embodiment includes an RDS decoder 16 for analyzing RDS data output from the tuner 12 and a Q-info circuit 17 for detecting the level of a signal received by the tuner 12. Have. The microcomputer 18 controls the RDS decoder 16 and the Q-info circuit 17 to acquire various information related to the received signal. The acquired information is used for a follow-up process described later. Also, part of the information can be displayed on a monitor (not shown) as character information or image information, or output from a speaker as a voice message. For example, traffic information (such as traffic congestion information on roads) may be included in the RDS data, and the user of the RDS receiver 1 can confirm the traffic information as text information or voice information.

  The microcomputer 18 has a built-in flash memory 18a, and a program executed by the microcomputer 18 and a filter table to be described later are stored in the flash memory 18a.

  FIG. 3 shows an example of the filter table. The filter table is a table in which SID (Service ID) and LTN (Location Table Number) included in TMC data and PI (Program Identifier) which is a program name of RDS broadcast corresponding to the combination of SID and LTN are described. It is.

  The CPU 18 can refer to the SID and LTN from the PI of the program by referring to this table. The RDS broadcast is a broadcast in which digital data is superimposed on an analog audio signal, and the same TMC data may be superimposed on a plurality of programs having different PIs. Therefore, as shown in FIG. 2, a plurality of PIs may be registered for a set of SIDs and IDs.

  Note that the SID is an identification number of the TMC service, and the LTN is an identification number of an area supported by the TMC service.

  A procedure of TMC channel selection processing for tuning to a frequency at which a desired TMC service is broadcast using the above filter table will be described. FIG. 3 is a flowchart of a TMC channel selection processing routine according to the present embodiment. This routine is executed when the user of the RDS receiver 1 operates the operation panel (not shown) of the RDS receiver 1 to call the TMC channel selection function.

  When this routine starts, step S1 is first executed. In step S1, scanning is performed using a PLL or the like, and a program having an arbitrary frequency is received. Next, the process proceeds to Step 2.

  In step S2, the reception state of the signal is examined, and it is determined whether or not a sufficient signal level is obtained. When it is determined that a sufficient signal level is obtained (S2: YES), the process proceeds to step S3. On the other hand, when it is determined that a sufficient signal level is not obtained (S2: NO), the process returns to step S1 to receive at other frequencies.

  In step S3, counting of the internal timer of the receiving device is started. Next, the process proceeds to step S4.

  In step S4, it is confirmed whether or not RDS data is included in the broadcast of the currently received frequency. If it is confirmed that RDS data is included (step S4: YES), the process proceeds to step S6. On the other hand, if RDS data cannot be detected (S4: NO), the process proceeds to step S5.

  In step S5, it is confirmed whether or not the count value of the timer set in step S3 has reached a predetermined value. If the count value has reached a predetermined value (S5: YES), it is determined that this broadcast does not include RDS data, and the process returns to step S1 to receive at another frequency. On the other hand, if the count value does not reach the predetermined value (S5: NO), it is determined that there is still a possibility that RDS data cannot be detected, and the process returns to step S4. That is, the routine of Steps S3 to S5 is a branching step in which if the RDS cannot be detected within a predetermined time, the process proceeds to Step S6, and if it cannot be detected, the process returns to Step S1 to test another frequency.

  In step S6, counting of the internal timer of the receiving device is started. Next, the process proceeds to step S7.

  In step S7, a predetermined amount of RDS data is read, and it is determined whether or not a PI code is included in the RDS data. If the PI code is included in the read RDS data (S7: YES), the process proceeds to step S9. If not included (S7: NO), the process proceeds to step S8.

  In step S8, it is confirmed whether the count value of the timer set in step S6 has reached a predetermined value. If the count value has reached a predetermined value (S8: YES), it is determined that the PI code acquisition has failed for this broadcast, and the process returns to step S1 to receive at another frequency. On the other hand, if the count value does not reach the predetermined value (S8: NO), it is possible that the PI code is included in other parts of the RDS data just by reading the part that does not include the PI code by chance. Is determined to remain, and the process returns to step S7. That is, the routine of steps S6 to S8 is a branching step that proceeds to step S9 if the PI code cannot be detected within a predetermined time, and returns to step S1 to test another frequency if it cannot be detected.

  As shown in FIG. 3, the PI code is 4-digit hexadecimal numeric data. The first digit of the PI code indicates the country code. In RDS, the same country code is assigned to a plurality of countries, but countries having the same country code are geographically separated from each other, and therefore, broadcasts are received by an automobile that moves extremely long distances. Unless this is the case, it is possible to roughly specify the country receiving the broadcast only with the country code. As shown in FIG. 3, if the PI code is “Dxxx”, this broadcast is broadcast from a broadcasting station in Germany, Libya, or Yugoslavia. Here, if the car on which the RDS receiver 1 is mounted is one that moves mainly in Western Europe, it can be seen that the currently received program is broadcast from a German broadcasting station. In the present embodiment, the RDS receiver 1 is set to use the German TMC service, and in step S9, it is determined whether or not the first digit of the read PI code is D. If the first digit of the PI code is D (S9: YES), the process proceeds to step S10. On the other hand, if the first digit of the PI code is other than D (S9: NO), the process returns to step S1 to test other frequencies.

  In step S10, the acquired PI code is compared with the table of FIG. 3, and it is determined whether or not the same PI code as the acquired PI code is included in the table. If it is determined that the PI code is included in the table (S10: YES), the process proceeds to step S11.

  In step S11, the SID and LTN corresponding to the acquired PI code are read from the table. Then, the process proceeds to step S12.

  In step S12, the SID and LTN of the desired TMC service are compared with the SID and LTN read in step S11. That is, the SID and LTN corresponding to the acquired PI code are compared with the SID and LTN of the desired TMC service, and it is determined whether or not they match. If it is determined that the SID and LTN in the table corresponding to the PI code match the SID and LTN of the desired TMC service, this means that the currently received program provides the desired TMC service. . In this case (S12: YES), this routine is terminated. On the other hand, if a mismatch between SID or LTN is detected, it means that the program having this PI code does not provide the desired TMC service. In this case (S12: NO), the process returns to step S1 to test for other frequencies.

  On the other hand, if it is determined in step S10 that the PI code is not included in the table (S10: NO), the process proceeds to step S13.

  In step S13, counting of the built-in timer of the receiving apparatus is started. Next, the process proceeds to step S14.

  In step S14, it is determined whether RDS data has been acquired. If the RDS data has been acquired (S14: YES), the process proceeds to step S15. On the other hand, if acquisition of RDS data has failed (S14: NO), the process proceeds to step S18.

  In step S15, it is determined whether or not SID and LTN are included in the RDS data acquired in step S14. If SID or LTN is included in the RDS data (S15: YES), the process proceeds to step S16. On the other hand, if neither the SID nor the LTN is included in the acquired RDS data (S15: NO), the process proceeds to step S18.

  In step S16, the SID and / or LTN in the RDS data is compared with the SID and / or LTN of the desired TMC service. That is, the SID and LTN in the RDS data are compared with the SID and / or LTN of the desired TMC service, and it is determined whether or not they match. If it is determined that the SID and / or LTN in the RDS data does not match the SID and / or LTN of the desired TMC service, the currently received program does not provide the desired TMC service. It is. In this case (S16: NO), the process returns to step S1 to test for other frequencies. On the other hand, if a match between SID and / or LTN is detected (S16: YES), the process proceeds to step S17.

  In step S17, it is determined whether or not the comparison for both SID and LTN is completed in step S16. If it is determined that the comparison of only one of SID and LTN has been completed, the other of SID and LTN has not been acquired yet. In this case (S17: NO), the process proceeds to step S18. On the other hand, if it is determined that the comparison of both SID and LTN has been completed, this means that the program provides the desired TMC service. Therefore, in this case (S17: YES), the process proceeds to step S19.

  In step S19, the PI code acquired in S7 is registered in the filter table. That is, this PI code is stored in the area of the table corresponding to the desired SID and LTN. As a result, the table is updated, and when RDS data having this PI code is received from the next time, it is determined whether or not a desired TMC service is provided without going through steps S13 to S18. . Next, this routine is terminated.

  In step S18, it is confirmed whether the count value of the timer set in step S13 has reached a predetermined value. If the count value has reached the predetermined value (S18: YES), it is determined that acquisition of RDS data has failed for this broadcast, and the process returns to step S1 to receive at another frequency. On the other hand, if the count value has not reached the predetermined value (S18: NO), it is simply determined that the RDS data is being acquired, and the process returns to step S14. That is, the loop of steps S14 to S18 proceeds to step S19 if the acquisition of the SID and LTN is completed within a predetermined time and the SID and LTN match those of the desired TMC service, and the SID, LTN within the predetermined time. If the LTN cannot be acquired, or if the acquired SID and LTN are different from those of the desired TMC service, the process returns to step S1 to perform another frequency test.

  In steps S14 to S18, since the comparison is made in S16 immediately after acquiring the SID and LTN, whether or not the desired TMC service is provided immediately after the acquisition of both the SID and the LTN is completed. Can be made.

It is a flowchart of the TMC channel selection process in the conventional RDS receiver. It is a block diagram of the RDS receiver by embodiment of this invention. 2 shows an example of a filter table used in TMC channel selection processing in the embodiment of the present invention. It is a flowchart of the TMC channel selection process in the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 RDS receiver 11 Antenna 12 Tuner 13 Mute circuit 14 Amplifier circuit 15 Speaker 16 RDS decoder 17 Q-info circuit 18 Microcomputer 19 PLL circuit

Claims (6)

A TMC channel selection method for selecting a frequency for broadcasting a desired TMC service in RDS broadcasting,
A scanning step of detecting a receivable TMC broadcast;
A PI extraction step of extracting a PI code from the RDS data of the TMC broadcast detected in the scanning step;
A first PI determination step of determining whether or not the TMC broadcast corresponding to the extracted PI code provides a desired TMC service;
First TMC information is extracted from the RDS data of the TMC broadcast when it is determined in the first PI determination step that the TMC broadcast corresponding to the extracted PI code provides the desired TMC service; TMC information acquisition step of
When it is found in the first PI determination step that the TMC broadcast corresponding to the extracted PI code does not provide the desired TMC service, the scanning step is executed again to detect other TMC broadcasts A first re-scanning instruction step;
A TMC channel selection method in RDS broadcasting, characterized by comprising:   The first PI determination step refers to a table in which a PI code and a TMC service provided by the TMC broadcast having the PI code are associated with each other, and a TMC broadcast corresponding to the extracted PI code is a desired TMC. 2. The TMC channel selection method in RDS broadcasting according to claim 1, wherein it is determined whether or not a service is provided. Prior to the execution of the first PI determination step, a second PI determination step for determining whether the PI code extracted in the PI extraction step is registered in the table using the table;
When the second PI determination step reveals that the extracted PI code is not registered in the table, an identification code for identifying the TMC service is acquired from the RDS data of the TMC broadcast and extracted. A TMC discriminating step for discriminating whether or not a TMC broadcast corresponding to the PI code provides a desired TMC service using the identification code;
Second TMC information for extracting TMC information from RDS data of the TMC broadcast when it is determined in the TMC discrimination step that the TMC broadcast corresponding to the extracted PI code provides the desired TMC service. An acquisition step;
When the TMC determination step determines that the TMC broadcast corresponding to the extracted PI code does not provide a desired TMC service, the scanning step is executed again to detect another TMC broadcast. Re-scanning instruction step,
Further comprising
3. The first PI determination step is executed when it is found in the second PI determination step that the extracted PI code is registered in the table. The TMC channel selection method in the described RDS broadcast.   In the TMC determination step, when it is determined in the TMC determination step that the TMC broadcast corresponding to the extracted PI code provides the desired TMC service, the extracted PI code is associated with the TMC service The TMC channel selection method for RDS broadcasting according to claim 3, further comprising a table update step of registering in the table. Scanning means for detecting receivable TMC broadcasts;
PI extraction means for extracting a PI code from RDS data of TMC broadcast detected by the scanning means;
First PI determination means for determining whether the TMC broadcast corresponding to the extracted PI code provides a desired TMC service;
TMC information is extracted from the RDS data of the TMC broadcast when it is found from the discrimination result by the first PI discrimination means that the TMC broadcast corresponding to the extracted PI code provides the desired TMC service. First TMC information acquisition means;
When it is found from the determination result by the first PI determination means that the TMC broadcast corresponding to the extracted PI code does not provide the desired TMC service, the scanning step is executed again to execute another TMC broadcast. First rescanning instruction means for detecting
An RDS receiver characterized by comprising: A storage means for storing a table in which a PI code and a TMC service provided by the TMC broadcast having the PI code are associated;
6. The first PI discriminating unit discriminates whether or not the TMC broadcast corresponding to the extracted PI code provides a desired TMC service with reference to the table. The RDS receiver as described.

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