JPH03227135A - Receiving frequency selecting method in rds receiver - Google Patents

Abstract

PURPOSE:To receive positively a same network station of a different regional network by storing a PI data and an AF data of a current receiving station in response to a command and applying a prescribed processing. CONSTITUTION:The processor of a controller 13 stores a PI data and an AF data of a current receiving station into a memory 14 in response to a 1st command. Then the presence of another reception station based on the AF list is detected. When the PI data obtained from a detected broadcast wave of this receiving station is coincident with the PI data stored precedingly except the area code and each area code in the PI data dissident, the frequency of this receiving station is used as a new receiving frequency. When a 2nd command is raised, the processor restores the receiving frequency into the original receiving frequency given by the AF data.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a radio data system receiver (hereinafter referred to as RD).
This invention relates to a reception frequency selection method in a receiver (referred to as an S receiver).

BACKGROUND TECHNOLOGY When a general broadcasting station broadcasts a program, broadcast-related information such as information related to the program content is transmitted as data using multiplex modulation, and the receiving side demodulates the data and uses the data to determine the desired program content. There is a radio data system (RDS) that allows radio listeners to select the desired service.

In this radio data system, 3 of the 19KHz stereo pilot signal is outside the frequency band of the FM modulated wave.
The next harmonic, 57 KHz, is used as a subcarrier, and this subcarrier is filtered and biphase (Biphasic).
se) The radio data signal is amplitude-modulated using a data signal indicating broadcast-related information such as coded program content, and the amplitude-modulated subcarrier is frequency-modulated to the main carrier and then broadcast. The standards for this broadcasting system have been proposed by the European Broadcasting Union (EBU).

As is clear from FIG. 4, which shows the baseband coding structure of the radio data signal, 104 bits are divided into 1
Multiplex transmission is repeated as a group. A group consists of four blocks of 26 bits each, each block consisting of a 16 bit information word and a IO bit check word. In addition, each group is classified into 16 types (0 to 15) using 4 bits according to its content, and each type (0 to 15) is classified into A
, B are defined.

FIGS. 5(a) and 5(b) show the formats of types OA and OB groups, respectively. In type OA group (a), block 1 contains 16-bit program identification data (hereinafter referred to as PI data) consisting of a country code, area code, and program code, and block 2 contains a group type code and version code. (Bo)
, traffic information broadcasting station identification (TP) code, program content identification (PTY) code, etc. Block 3 contains station frequency data (hereinafter abbreviated as AF data) of network stations broadcasting the same program. ), and broadcast station name data (hereinafter abbreviated as PS data) is arranged in block 4, respectively. On the other hand, type OB group (b)
In the case of the type OA group, only the contents of block 3 are different from those of the type OA group, and the PI data is arranged in block 3. That is, the AF data of the network station is transmitted only in the type OA group, and the PS data is transmitted in the type OA and OB groups.

In this way, the radio pig signal of the type OA group also includes AF data of a network station broadcasting the same program as the broadcast station currently being received. Therefore, at the time of reception, the AF data obtained by demodulation and P
Import the I data and store it as an AF list.
For example, if the reception sensitivity of the broadcasting station currently being received decreases due to disturbances such as multipath interference, the AF
The so-called network function 4-o checks whether the received program is correct according to the AF list by selecting other stations in the same network station group based on the list and then comparing the PI data.
- (Network Follow) function allows you to listen to the same program with good reception at all times without being affected by disturbances.

Since there are stations on the same network with different area codes in their P1 data, this network follow function has two modes: Regional OFF mode, which ignores area codes during PI checks, and PI checks, which include area codes. There is a regional ON mode that performs the following.

In the regional OFF mode, the same network station may be received outside the area (hereinafter referred to as regional) where the broadcast station currently being received exists.

However, when a user requests to actively receive the same network station in a different region, that is, the same network station in the destination region, the conventional network follow function cannot respond to this request and is inconvenient. Ta.

SUMMARY OF THE INVENTION [Object of the Invention] Therefore, an object of the present invention is to provide a reception frequency selection method in an RDS receiver that enables active reception of different regional same network stations.

[Structure of the Invention] The receiving frequency selection method according to the present invention is based on the current receiving frequency in an RDS receiver capable of receiving RDS broadcast waves on which multiple AF data of the same network station group and PI data including area codes are superimposed. A reception frequency selection method for switching the reception frequency to another same network station frequency given by one of the plurality of AF data, the AF being obtained from the broadcast wave of the current reception frequency in response to a first command.
a first step of holding data and PI data; a second step of detecting the presence of a receiving station based on the plurality of AF data; A third step of detecting that the PI data held in the first step matches the area code except for the area code, and a third step of detecting that the area code in the PI data obtained in the third step matches the PI data held in the first step. A fourth step in which the frequency of the receiving station is set as the new receiving frequency when a mismatch is detected with the area code of
It consists of a fifth step of returning to the current reception frequency given by the AF data held in the step.

[Operation of the invention] In the receiving frequency selection method according to the present invention, the AF data and PI data of the current receiving station are held in response to the first command, and the presence of the receiving station is detected based on the AF list. , the PI data obtained from the broadcast wave of the receiving station matches the previously held PI data except for the area code,
If the area codes in these PI data do not match, the frequency of that receiving station will be set as the new receiving frequency, and if a second command is issued afterwards, the receiving frequency will be held first. Return to the original receiving frequency given by AF data.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram schematically showing the basic configuration of an RDS receiver to which a receiving frequency selection method according to the present invention is applied. In the figure, the FM multiplex broadcast wave received by antenna 1 is selected by a front end 2, converted to an intermediate frequency (IF), and then sent to FM via IF amplifier 3.
The signal is supplied to the detector 4. The front end 2, for example,
PLL using PLL circuit including programmable frequency divider
It adopts a single synthesizer type, and is configured to perform channel selection by controlling the frequency division ratio of a programmable frequency divider by a controller 13, which will be described later. The detection output of the FM detector 4 is supplied to an MPX (multiplex) demodulation circuit 5, and in the case of stereo broadcasting, it is output from L (left) and R (
The audio signal of the right) channel is separated and passes through the muting circuit 18 to become a reproduced audio output. The muting circuit 18 is turned on and off by the controller 13.
Off control is performed.

Further, when the detection output of the FM detector 4 passes through the filter 6, a 57 KHz subcarrier, that is, a radio data signal, amplitude modulated by the biphase coded 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. In the D-PLL circuit 8, the PLL
A clock for data demodulation is generated based on the demodulated output of the circuit 7. In the decoder 9, the biphase coded data signal which is the demodulated output of the PLL circuit 7 is
It is decoded in synchronization with the clock generated by the LL circuit 8. The lock detection circuit 10 detects the locked state and unlocked state of the D-PLL circuit 8, and switches and controls the lock ranges of the PLL circuit 7 and the D-PLL circuit 8 based on the detection output.

As shown in FIG. 4, the output data of the decoder 9 is in groups of 104 bits each consisting of 4 blocks each having a 26-bit configuration, and the data is sequentially grouped.

The signal is supplied to the block synchronization & error detection circuit 11.

The group and block synchronization & error detection circuit 11 performs group and block synchronization based on the 10-bit offset word assigned to the 10-bit check word of each block, and also performs 16-bit information based on the check word. Word error detection is performed. Then, the error-detected data is error-corrected in the next-stage error correction circuit 12, and then the controller 1
3.

The controller 13 is constituted by a microcomputer, and is configured to collect code information for each block of radio data that is sequentially input in groups, i.e., PI data, AF data, PS data, etc. related to the program content of the broadcasting station currently being received. The data information is captured and stored in the memory 14, and the frequency division ratio of a programmable frequency divider (not shown) of the PLL circuit that constitutes 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.

In addition, a level detection circuit 16 detects the received signal level (field strength) based on the IF signal level in the IF amplifier 3, and a so-called S curve characteristic in the FM detector 4 when the IF signal level in the IF amplifier 3 is equal to or higher than a predetermined level. A station detection circuit 17 is provided which detects a receiving station and outputs a station detection signal when the detection output of the level detection circuit 16 is within a predetermined level range. The station detection signal output from the controller 13 is supplied to the controller 13.

Next, when a regional channel selection command is issued from the operation unit 15 by a key operation by the user, the controller 1
The processing procedure for regional channel selection executed by processor No. 3 will be explained with reference to the flowchart of FIG. It is assumed that this routine is called and executed by the first command, which is a regional channel selection command.

Further, it is assumed that the memory 14 has already taken in AF data obtained by demodulating received broadcast waves, and has already created an AF list of stations on the same network as the broadcast station currently being received.

First, the processor takes in the AF data and PI data of the broadcast wave currently being received, stores them in a predetermined area of the memory 14 (step S1), and reads out the AF data of 1 in the list from the memory 14 according to the previous AF list. Step S2), then turn on the muting circuit 18 to mute the audio (step S3), and then transfer the read AF data to the front end 2.
The PLL circuit is output to the LL circuit (not shown) (step S4), and at the same time the PLL circuit is output for the time T1 required for the PLL circuit to lock.
A timer is set (step S5). The AF data supplied to the PLL circuit is set in a programmable frequency divider within the PLL circuit, and the reception frequency changes from the current reception frequency to another network station frequency during a period until the PLL timer times up.

After the PLL timer times up (step S6), the processor determines whether or not a receiving station exists by monitoring the output of the station detection signal from the station detection circuit 17. In step S7), the processor detects the presence of the receiving station. If so, the PI data of the receiving station is fetched (step S8), and it is determined whether this PM data and the PI data held in step S1 match except for the area code.
9), if they match, it is further determined whether the area code in the PI data imported this time does not match the area code in the PI data held in step S1 (step 510); if they do not match, The muting circuit 18 is turned off to cancel audio muting (step 511).

Then, the processor determines whether or not a return command, which is the second command, is issued from the operation unit 15 by the user's key operation (step 512), and if the return command is not issued, the processing of this routine ends. .

As a result, a broadcasting station with a different area code, that is, a different regional same network station, is selected from among the same network station group as the broadcasting station currently being received.

If it is determined in step S7 that there is no receiving station, if it is determined in step S9 that the PI data do not match, or if it is determined that the area codes match in step S10, the processor receives It is determined whether or not the processing of checking the presence of a station, comparing the PI data for coincidence excluding the area code, and comparing the area code for non-coincidence is completed (step 813).
, if the process has not been completed, the process returns to step S2 and the above-described process is repeated. When the processing is completed for all of the AF list, the processor reads the original AF data held in step S1 (step 514), and then outputs the read AF data to the PLL circuit (step 5).
15), and simultaneously set the PLL timer (step 516).

Then, after the PLL timer times up (step 5)
17), the muting circuit 18 is turned off to cancel the audio mute (step 518), and then the process of this routine ends.

This means that the receiving frequency has returned to the original frequency of the receiving station. In other words, when selecting a regional same network station by issuing a regional channel selection command, the presence of the receiving station cannot be detected or the receiving station is separated.
If the same network station does not exist, the receiving station returns to the original receiving station.

After canceling mute in step S11, step 51
If it is determined in step S2 that a return command, which is the second command, has been issued, the processor turns on the muting circuit 18 to mute the audio (step 519), and then proceeds to step S14. According to this, even if the original regional becomes unknown while searching for the same network station as the receiving station currently being listened to, it is possible to easily return to the original regional by issuing a return command by key operation. It is possible to return to receiving the same regional network station.

FIG. 3 is a flowchart showing another processing procedure, and steps that perform the same processing as in FIG. 2 are denoted by the same reference numerals. In this example, after the mute is released in step S11, a return timer for a certain period of time T2 is set (step 520), and the operation unit 15 is set within a certain period of time T2 until the timer times up.
In step S, watch for the return command to be issued.
14.521), if a return command is not issued before the time-up, the process of this routine is directly terminated, and if a return command is issued, the process proceeds to step S19. As a result, the return command is accepted for a certain period of time T2 after canceling mute.
It will only be done internally.

In addition, in each of the above embodiments, when selecting the same network station in different regions, P
Although only the presence of a receiving station is detected (step S7) before determining whether the I data matches (step S9) and the area code mismatches (step 510), the presence of the receiving station is detected, the It is also possible to take in the received signal level from the level detection circuit 16 and move to step S8 after detecting that the received signal level is equal to or higher than a set level.

As described in detail of the invention, in the receiving frequency selection method according to the present invention, the AF data and PI data of the current receiving station are held in response to the first command, and the AF data and PI data of the current receiving station are retained based on the AF list. When the presence of the receiving station is detected and the PI data obtained from the broadcast wave of the receiving station matches the previously held PI data except for the area code, and each area code in these PI data does not match, the receiving station By setting this frequency as a new reception frequency, it becomes possible to actively receive stations on the same network on different sides.

In addition, if a second command is issued after receiving the same network station as the separate channel, by returning the receiving frequency to the original receiving frequency given by the previously held AF data, Separate from the receiving station - Even if the original regional becomes unknown while searching for the same regional network station, you can easily receive the same original regional network station by issuing a return command by key operation. You will be able to return to

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of an RDS receiver to which the receiving frequency selection method according to the present invention is applied, and FIG. 2 shows an example of the processing procedure for regional tuning, which is the receiving frequency selection method according to the present invention. 3 is a flowchart showing another example of such processing procedure, FIG. 4 is a diagram showing the baseband coding structure of radio data, and FIG. 5 is a flowchart showing another example of such processing procedure.
It is a figure which shows the format of b). Explanation of symbols of main parts 2...Front end 4...F
M detector 5...Multiplex demodulation circuit 8.
...Digital PLL circuit

Claims (2)

[Claims] (1) RDS in which multiple frequency data of the same network station group and program identification data including area code are superimposed
A reception frequency selection method for switching the reception frequency from the current reception frequency to another same network station frequency given by one of the plurality of frequency data in an RDS receiver capable of receiving broadcast waves, the method comprising: responding to a first command; a first step of holding frequency data and program identification data obtained from broadcast waves of the current received frequency; a second step of detecting the presence of a receiving station based on the plurality of frequency data; and a second step of detecting the presence of a receiving station based on the plurality of frequency data. a third step of detecting that the program identification data obtained from the broadcast wave of the received station that was received matches the program identification data held in the first step except for the area code; and the program identification obtained in the third step. a fourth step of setting the frequency of the receiving station as a new receiving frequency when it is detected that the area code in the data does not match the area code in the program identification data held in the first step; A receiving frequency selection method comprising a fifth step of returning the receiving frequency to the current receiving frequency given by the frequency data held in the first step in response to the second command after the completion of the receiving frequency selection method. (2) The receiving frequency selection method according to claim 1, wherein the fifth step responds to the second command only within a certain period of time after the end of the fourth step.