JP2848895B2 - Receiving method in RDS receiver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a radio data system receiver (hereinafter referred to as RD).
S receiver).

2. Description of the Related Art At the time of program broadcasting of a general broadcasting station, broadcast-related information such as information related to the program content is transmitted as data by multiplex modulation, and the desired program content is demodulated on the receiving side based on the demodulated data. There is a radio data system (RDS) that allows the user to select a service and provide that service to radio listeners.

In this radio data system, 57 kHz, which is the third harmonic of the 19 KHz stereo pilot signal outside the frequency band of the FM modulation wave, is used as a subcarrier, and the subcarrier is filtered and biphase-coded. A radio data signal is amplitude-modulated by a data signal indicating information related to broadcasting such as contents, and the amplitude-modulated sub-carrier is frequency-modulated to a main carrier for broadcasting. Has been proposed by the European Broadcasting Union (EBU).

As is clear from FIG. 3 showing the baseband coding structure of the radio data signal, 104 bits correspond to 1 bit.
It is repeatedly multiplexed and transmitted as a group. One group is composed of four blocks each having a 26-bit configuration, and each block is composed of a 16-bit information word and a 10-bit check word. Each group is classified into 16 types of types 0 to 15 by 4 bits according to the contents, and two versions of A and B are defined for each type (0 to 15).

FIGS. 4 (a) and 4 (b) show the formats of the type 0A and 0B groups, respectively. In the type 0A group (a), block 1 includes 16-bit program identification data (hereinafter referred to as PI data) including a country code, an area code, and a program code, and block 2 includes a group type code and a version code. (B ₀ ), various codes such as a traffic information broadcasting station identification (TP) code and a program content identification (PTY) code are stored in block 3 as station frequency data (hereinafter referred to as AF) of a network station broadcasting the same program. In the block 4, broadcast station name data (hereinafter, abbreviated as PS data) is arranged. On the other hand, in the type 0B group (b), only the contents of the block 3 are different from those in the type 0A group, and the block 3 has PI data. That is, the AF data of the network station is transmitted only in the type 0A group, and the PS data is transmitted in the type 0A and 0B groups.

As described above, the radio data signal of the type 0A group includes the AF data of the network station that broadcasts the same program as the currently receiving broadcast station. Therefore, during reception, the AF data and PI
Take in the data and store it as an AF list.For example, if the reception sensitivity of the currently receiving broadcast station decreases due to disturbance such as multipath interference, the same network station group based on the previously stored AF list Select another station,
Furthermore, the so-called PI check that compares PI data
The so-called Network Foll, which checks whether the received program is correct according to the AF list
With the ow) function, the same program can always be heard in a good reception state without being affected by disturbance.

In this network follow function, even if the same network station has an area code in the PI data or a different station, the regional (Regional) OFF mode that ignores the area code during PI check and the PI check including the area code And a regional ON mode. In the regional OFF mode, outside the area where the currently receiving broadcasting station exists (hereinafter, referred to as another regional)
May receive the same network station.

However, when there is a request from the user to actively receive the same network station in another regional, that is, the same network station in the destination regional, the conventional network follow function cannot cope with this, which is inconvenient.

SUMMARY OF THE INVENTION [Object of the Invention] Accordingly, an object of the present invention is to provide a method of selecting a reception frequency in an RDS receiver capable of positively receiving the same network station in another region.

[Configuration of the Invention] A reception method according to the present invention is a reception method in an RDS receiver capable of receiving an RDS broadcast wave on which program identification data including a plurality of frequency data and an area code of the same network station group is superimposed, A first step of holding program identification data obtained from a broadcast wave of the current reception frequency, a second step of detecting the presence of a receiving station based on the plurality of frequency data, and a broadcast of the receiving station detected in the second step The program identification data obtained from the wave is compared with the program identification data held in the first step, and when it is detected that the areas other than the area code match and the area codes do not match, the frequency of the current receiving station is changed to a new frequency. And a third step of setting the reception frequency.

[Advantage of the Invention] In the receiving frequency selecting method according to the present invention, the PI data of the current receiving station is held in response to the command, the presence of the receiving station based on the AF list is detected, and the broadcasting of the receiving station is performed. When the PI data obtained from the wave matches with the previously held PI data except for the area code, and each area code in these PI data does not match, the frequency of the current receiving station is set as a new receiving frequency .

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram schematically showing a basic configuration of an RDS receiver to which a receiving frequency selection method according to the present invention is applied. In the figure, a desired station is selected by a front end 2 from an FM multiplex broadcast wave received by an antenna 1 and converted to an intermediate frequency (IF).
Supplied to The front end 2 adopts, for example, a PLL synthesizer method using a PLL circuit including a programmable frequency divider, and performs a channel selection operation by controlling the frequency division ratio of the programmable frequency divider by a controller 13 described later. Has become. The detection output of FM detector 4 is MP
The signal is supplied to an X (multiplex) demodulation circuit 5, and is separated into L (left) and R (right) channel audio signals in the case of a stereo broadcast, and becomes a reproduced audio output via a muting circuit 18. On / off control of the muting circuit 18 is performed by the controller 13.

When the detection output of the FM detector 4 passes through the filter 6, a 57 KHz subcarrier amplitude-modulated by the biphase-coded data signal, that is, a radio data signal is extracted and demodulated by the PLL circuit 7. . This demodulated output is supplied to a digital (D) PLL circuit 8 and a decoder 9.
Supplied to In the D-PLL circuit 8, a clock for data demodulation is generated based on the demodulated output of the PLL circuit 7. The decoder 9 decodes the biphase-coded data signal, which is the demodulated output of the PLL circuit 7, in synchronization with the clock generated by the D-PLL circuit 8. The lock detecting circuit 10 detects the locked state and the unlocked state of the D-PLL circuit 8, and outputs the PLL circuit 7 and the D-PLL based on the detection output.
The lock range of the circuit 8 is switched and controlled.

As shown in FIG. 3, the output data of the decoder 9 is in units of 104 bits consisting of four blocks each having a 26-bit configuration, and is sequentially supplied to the group / block synchronization & error detection circuit 11. The group / block synchronization & error detection circuit 11 synchronizes the group with the block based on the 10-bit offset word assigned to the 10-bit check word of each block, and 16-bit information based on the check word. Word error detection is performed. Then, the error-detected data is supplied to the controller 13 after the error is corrected by the error correction circuit 12 at the next stage.

The controller 13 is constituted by a microcomputer, and code information of each block in the radio data sequentially input in group units, that is, radio data such as PI data, AF data, PS data, etc. relating to the program content of the currently receiving broadcast station. The data information is fetched and stored in the memory 14, and the frequency division ratio of a programmable frequency divider (not shown) of the PLL circuit constituting a part of the front end 2 is determined based on a channel selection command from the operation unit 15. Perform network follow function by controlling.

Also, a level detection circuit 16 for detecting a reception signal level (electric field strength) based on the IF signal level in the IF amplifier 3.
And a station detection circuit for detecting a receiving station and outputting a station detection signal when the IF signal level in the IF amplifier 3 is equal to or higher than a predetermined level and the detection output of so-called S curve characteristics in the FM detector 4 is within a predetermined level range. 17 is provided,
The received signal level detected by the level detection circuit 16 and the station detection signal output from the station detection circuit 17 are supplied to the controller 13.

Next, when a regional tuning command is issued from the operation unit 15 by a key operation by the user, the controller 13
2 will be described with reference to the flowchart of FIG. This routine is called and executed by a regional tuning command. In addition, AF data obtained by demodulating the received broadcast wave is fetched into the memory 14 and is stored in the same network station as the currently receiving broadcast station.
It is assumed that the AF list has already been created.

First, the processor fetches the AF data and PI data of the currently received broadcast wave, stores them in a predetermined area of the memory 14 (step S1), and stores one of the ones in the list according to the previous AF list.
Is read from the memory 14 (step S2), the muting circuit 18 is turned on to mute the sound (step S3), and the read AF data is then read out by a PLL circuit (not shown) in the front end 2. output to) (step S4), and sets the PLL timer time T ₁ required to lock the PLL circuit at the same time (step S
Five). The AF data supplied to the PLL circuit is set in a programmable frequency divider in the PLL circuit, and the reception frequency changes from the current reception frequency to another network station frequency until the PLL timer times out.

After the expiration of the PLL timer (step S6), the processor determines whether or not a receiving station exists by monitoring the output of the station detection signal from the station detecting circuit 17 (step S7). Is detected, the PI data of the receiving station is fetched (step S8), and the area code in the PI data is stored and held in a predetermined area of the memory 14 (step S9). Subsequently, the processor determines whether or not the PI data acquired this time matches the PI data held in step S1 except for the area code (step S1).
S10) If they match, it is further determined whether or not the area code in the PI data acquired this time does not match the area code in the PI data held in step S1 (step S11). The muting circuit 18 is turned off to release the audio mute (step S1).
2).

As a result, a broadcasting station having a different area code from the same network station group as the currently receiving broadcasting station, that is, the same network station in a different region is selected.

After unmute at step S12, the processor may set the regional timer for a predetermined time T ₂ (step S13), and the timer previous regional tuning command from the operating unit 15 within a predetermined time T ₂ of the until time is up Is monitored again (step S1
4, S15). If the regional tuning command is not issued until the time is up, the processor terminates the processing of this routine as it is, and if the regional tuning command is issued, returns to step S2 and follows the AF list. The above process is repeated by reading other AF data in the list from the memory 14. During this process,
In step S11, it is determined whether or not the area code in the currently acquired PI data and the area code in the PI data held in step S1 do not match all of the area codes held up to the previous time in step S9. Will be.

That is, after one in the same network station group for another regional is tuned, by emitting regional tuning command again within a predetermined time T _2, the other 1 Kyokugasen in another regional identity network station group By repeating this operation, it is possible to select the same network station of an arbitrary regional from the same network station group of another regional.

If it is determined in step S7 that there is no receiving station, if it is determined that the PI data does not match in step S10, or if it is determined that the area codes match in step S11, the processor receives all the AF lists. It is determined whether or not the process of checking the existence of the station, comparing the PI data except the area code, and comparing the mismatch of the area codes is completed (step S16). If not completed, return to step S2. The above processing is repeated. If the processing has been completed for all the AF lists, the processor reads the original AF data held in step S1 (step S17), and then reads the read AF data into the PLL.
Output to the circuit (step S18), and at the same time, set the PLL circuit timer (step S19). Then, after the PLL timer times out (step S20), the process proceeds to step S12 to cancel the audio mute.

As a result, the reception frequency has returned to the original reception station frequency. That is, when a regional tuning command is issued to select the same network station of another regional station, if the presence of a receiving station cannot be detected, or if the same network station of another regional station does not exist, the original Will be returned to the receiving station.

In the above embodiment, when selecting the same network station in another region, the PI except for the area code is selected.
Prior to the determination of data match (step S10) and area code mismatch (step S11), only the presence of the receiving station is detected (step S7). It is also possible to take in the signal level from the level detection circuit 16 and proceed to step S8 after detecting that the received signal level is equal to or higher than the set level.

As described above, in the receiving frequency selection method according to the present invention, the PI data of the current receiving station is held in response to the command, the presence of the receiving station based on the AF list is detected, and the When the PI data obtained from the broadcast wave of the receiving station matches except for the previously held PI data and the area code, and when each area code in these PI data does not match,
By setting the frequency of the receiving station this time as a new receiving frequency, the same network station in another region can be positively received.

[Brief description of the drawings]

FIG. 1 shows a case where a receiving frequency selecting method according to the present invention is applied.
FIG. 2 is a block diagram showing a basic configuration of an RDS receiver, FIG. 2 is a flowchart showing an example of a processing procedure of a regional channel selection which is a reception frequency selecting method according to the present invention, and FIG. 3 shows a baseband coding structure of radio data. Diagram,
FIG. 4 is a diagram showing the format of group types 0A (a) and 0B (b). Explanation of main part codes 2 ... Front end, 4 ... FM detector 5 ... Multiplex demodulation circuit 8 ... Digital PLL circuit 13 ... Controller, 14 ... Memory

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Akira Hayama, Inventor 25-1, Nishimachi, Yamada, Kawaji, Kawagoe, Saitama Prefecture Inside the Pioneer Corporation Kawagoe Plant (72) Inventor Yoshio, 25-25, Nishimachi, Yamagata, Kawagoe, Saitama Pioneer Corporation Kawagoe Factory (72) Inventor Kawabata et al. Pioneer Corporation 1-4-1 Meguro, Meguro-ku, Tokyo (56) References JP-A-1-151319 (JP, A)

Claims (3)

(57) [Claims] 1. A plurality of frequency data of the same network station group and program identification data including an area code are superimposed.
A receiving method in an RDS receiver capable of receiving an RDS broadcast wave, comprising: a first step of holding program identification data obtained from a broadcast wave of a current reception frequency; and detecting presence of a receiving station based on the plurality of frequency data. And comparing the program identification data obtained from the broadcast wave of the receiving station detected in the second step with the program identification data held in the first step, and the other than the area code matches and the area code is And a third step of setting the frequency of the current receiving station to a new receiving frequency when the mismatch is detected. 2. In the third step, the area code in the obtained program identification data is held, and the discrepancy between the area code in the program identification data obtained this time and all the area codes held up to the previous time is checked. The receiving method according to claim 1, wherein the detecting is performed. 3. When a command for performing the first stroke is issued again within a predetermined time after the end of the third stroke,
3. The receiving method according to claim 1, wherein the execution of the second and third steps is repeated.