JPH01204529A - Control method for rds receiver - Google Patents

Abstract

PURPOSE:To attain quick changeover to other same network station frequency with an excellent state by stopping the readout of an AF data being the discrimination of the dissidence of a PI data in the discrimination process when the readout of the AF data is circulated once in the readout process if the reception state of a broadcast wave during reception is deteriorated. CONSTITUTION:If the same program tracking command is published due to the deterioration in the reception state of a broadcast wave at the present reception frequency or the like, the frequency (AF) data of the same network station stored is read sequentially, the reception frequency is switched to the frequency supplied from the AF data to check the reception signal level and the program identification(PI) data. After the switching of the reception frequency by all the AF data is finished, the AF data not coincident with the data of the received broadcast wave in the PI data is neglected and the reception frequency is switched to the frequency fed from other AF data only to seek the broadcast wave of the same network station with excellent reception state. Thus, the same program is quickly switched to the broadcast wave to be listened by the excellent reception state.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a radio data system receiver (hereinafter referred to as RD).
The present invention relates to a control method for the S receiver.

Background Art When a broadcast station broadcasts, broadcast-related information such as information related to the program content is transmitted as data through multiplex modulation, and the receiving side can select the desired program content based on the demodulated data. The Radio Data System (RD), which was able to provide its services to radio listeners,
There is S).

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).
sc) The radio data signal is amplitude-modulated with 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. There is.

As is clear from Figure 3, 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, and each block consists of a 16 bit information word and a 10 bit check word. In Figure 4, block 1 includes program recognition, 2 (PI) representing the network;
block 2 contains traffic program recognition (TP) data and traffic announcement recognition (TA) data;
Block 4 contains frequency (AF) data of a group of network stations broadcasting the same program, and block 4 contains program service name information (PS) data such as broadcasting station names and network names. Furthermore, each group is classified into 16 types, 0 to 15, using 4 bits depending on its content, and furthermore, 2 types, A and B, are assigned to each type (0 to 15).
Two versions are defined and their recognition codes are placed in block 2. Note that the AF data of the network station is transmitted only in the type OA group.

By the way, in the case of a vehicle-mounted receiver, the reception condition of the broadcast wave being received may deteriorate as the vehicle travels.

In the case of RDS broadcasting, as mentioned above, when one RDS broadcast wave is received, the AF data of a group of network stations broadcasting the same program can be obtained, so this AF
Using the data, it is possible to switch the reception frequency to another same network station frequency with good reception conditions.

However, the AF data of the same network station group may include frequencies that are also used by other different network stations, and in such cases, switching the receiving frequency to the frequency of another same network station may be necessary. may not be done quickly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned points, and provides a method for switching the reception frequency to another same network station frequency where the reception condition is good when the reception condition of the broadcast wave being received has deteriorated. An object of the present invention is to provide a control method for an RDS receiver that can quickly perform the following steps.

In the RDS receiver control method of the present invention, when an RDS receiver capable of receiving RDS broadcast waves including program recognition data representing a network and equipped with a frequency data list of the same network station group is given a command to follow the same program. a readout step in which frequency data is sequentially read out from the frequency data list; a switching step in which the reception frequency is switched to the frequency given by the frequency data read out in the readout step; A determination step for determining whether a broadcast wave whose signal level is equal to or higher than a set level and whose program recognition data matches the received broadcast wave is received; and a determination step in which the received signal level is equal to or higher than the set level and program recognition is performed. This is a control method that includes a control process that stops switching the reception frequency in the switching process according to the determination result of data matching, and stores the determination result in the determination process, and in the reading process, when the reading of frequency data has completed one cycle. The present invention is characterized in that reading of frequency data determined in the determination process as not matching the program recognition data is stopped.

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

In FIG. 1 showing an example of the configuration of an RDS receiver to which the control method according to the present invention is applied, FM multiplex broadcast waves received by an antenna 1 are selected by a front end 2, and a desired station is selected by an intermediate frequency (IF). After being converted to IF amplifier 3
The signal is supplied to the FM detector 4 via the FM detector 4. front end 2
For example, the system employs a PLL synthesizer using a PLL circuit including a programmable frequency divider, and performs channel selection by controlling the frequency division ratio of the programmable frequency divider by a controller 14, which will be described later. There is. The detection output of the FM detector 4 is supplied to an MPX (multiplex) demodulation circuit 5, and in the case of stereo broadcasting, L(
The audio signal is separated into left (left) and R (right) channel audio signals and becomes a reproduced audio output. Muting circuit 20
is controlled on and off by the controller 14.

Furthermore, 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 pie-phase encoded 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. The generated clock is supplied to the gate circuit 10. The lock detection circuit 11 detects that the D-PLL circuit 8 is locked, generates a lock detection signal, supplies this to the gate circuit 10, and controls the circuit 10 to open. In the decoder 9, the biphase coded data signal which is the demodulated output of the PLL circuit 7 is decoded in synchronization with the clock generated by the D-PLL circuit 8.

As shown in FIG. 3, 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.

It is supplied to the block synchronization & error detection circuit 12.

The group and block synchronization & error detection circuit 12 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 13, and then the controller 1
4.

The controller 14 is constituted by a microcomputer, and includes code information of each block in radio data that is sequentially input in groups, that is, radio data information related to the program content of the broadcasting station currently being received (the above-mentioned PI
data, AF data, PS data, etc.) and stored in the memory 15, and based on the channel selection command from the operation unit 16, a programmable frequency divider (not shown) of the PLL circuit that constitutes a part of the front end 2. The channel selection operation is performed by controlling the reception frequency data value that determines the frequency division ratio of (1).

In addition, a level detection circuit 17 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 18 is provided which detects a receiving station and outputs a station detection signal when the detection output of the level detection circuit 17 is within a predetermined level range. A station detection signal output from the controller 14 is supplied to the controller 14.

Next, the procedure of the control method according to the present invention executed by the processor of the controller 14 will be explained according to the flowchart shown in FIG. 2 (Ta, Yama). Note that the first storage area of the memory 15 stores AF data obtained by demodulating received broadcasts, and stores n AF data lists f, , f of the same network stations as the broadcast station currently being received.
2...assume that fn has already been stored.

First, the processor determines whether the reception condition of the broadcast wave at the current reception frequency has deteriorated by monitoring whether the received signal level Vs from the level detection circuit 17 is lower than the set level Vo.Step S1), vs If ≦Vo, it means that the reception condition has deteriorated, and A is stored in memory 15.
It is determined whether the F data list exists (step 32).

If an AF data list exists, the same program tracking mode will be activated, and the PI data obtained from the currently received broadcast wave and its A
The F data is taken in and held in a register or the like (step S3). Then, set the variable M equal to 0 and the variable N equal to 1.
(step 84), reads the Nth AF data fN in the list from the memory 15 according to the AF data list (step S5), and outputs this AF data to a PLL circuit (not shown) in the front end 2. Performs tuning operation (step S6)
. Then, it is determined whether the received signal level Vs obtained from the level detection circuit 17 exceeds the set level Vo (step S7), and if VS > VO, PI data representing the network of the receiving station is fetched (step S8). ), this PI data is held in a register etc.
Determine whether it matches the I data (step S9)
.

If it is determined in step S7 that Vs≦Vo, or if it is determined that the PI data match in step S9, 1 is added to the variable M (step 510), and the read AF data of N programs is already stored in the memory 15. is written in the Mth position of the second storage area different from the first storage area (step 511), and whether or not all the AF data stored in the first storage area of the memory 15 has been read out (step 511).
N-n) (step 512).

On the other hand, if it is determined in step S9 that the PI data do not match, it means that another different network broadcast wave has been received, and in this case, the process immediately proceeds to step S12.
Do not write to the second storage area. Step S
12, all AF data is not read out (Nu
n), add 1 to the variable N in step 8.
13), and returns to step S5 to read new AF data from the first storage area. Once all the AF data has been read from the first storage area of the memory 15, a predetermined time T (for example, 60 seconds) is set in a timer (not shown) to start time measurement (step 514), and the variable N is set to 1. (step 515). Then, the Nth AF data is read from the second storage area of the memory 15 (step 516), and a tuning operation is performed by outputting this AF data to the PLL circuit of the front end 2 (step 517). Next, the received signal level Vs obtained from the level detection circuit 17 is set to the set level Vo.
Step 518), VS
>If VO, P representing the network of the receiving station
Import the I data (step 519) and import the imported P data.
It is determined whether the I data matches the PI data held in a register or the like (step 520). Vs≦Vo
, or even if VS > V
It is determined whether all the AF data stored in the second storage area No. 5 has been read out (whether or not it is N-M) (step 521). If it is determined that all the AF data has not been read out from the second storage area (N<M), 1 is added to the variable N (step 522), and step s16.
Returning to , the Nth AF data in the second storage area is read. On the other hand, if it is determined that all the AF data has been read from the second storage area, it is determined whether the timer has completed measuring the predetermined time T (step 823). If the timer has not completed time measurement, step S1
Returning to step 5, the selection of the same network station with good reception status is repeated according to the AF data list in the second storage area.

When the timer completes time measurement, it is assumed that it is currently impossible to select the same network station with good reception status, and this routine is terminated to return to the receiving frequency immediately before starting the same program tracking mode. .

If it is determined in step S20 that the PI data match, the mode shifts to normal reception mode using the same network station frequency currently being received as the reception frequency.

In this manner, in the same program following mode, first, the AF data obtained from the received broadcast waves and stored in the first storage area of the memory 15 are sequentially read out, and the frequency given by the AF data becomes the reception frequency. The AF data for which the received signal level Vs was below the set level Vo and the AF data for which the received signal level Vs exceeded the set level Vo and whose PI data matched the network station that was being received until just before starting the same program tracking mode are stored in the memory. A that was written to the second storage area of 15 and the PI data did not match.
F data is not written to the second storage area. Then,
The AF data written in the second storage area of the memory 15 is sequentially read out, and the frequency given by the AF data becomes the reception frequency. Then, until the predetermined time T has elapsed, the AF data is repeatedly and sequentially read out from the second storage area until the reception signal level Vs exceeds the set level Vo and the frequency given by the AF data with which the PI data matches becomes the reception frequency. It is.

In the above-described embodiment, even if Vs>Vo in step S7 and the PI data match in step S9, all AF data in the first storage area is read out and the receiving frequency is set as the frequency corresponding to the AF data. Then, the process proceeds to step S13, but in such a case, the same program following mode may be ended and the normal reception mode may be returned to, with the frequency given by the AF data whose PI data matches being set as the reception frequency.

Furthermore, in the above embodiment, when the received signal level Vs falls below the set level Vo, the same program following command is automatically generated and the same program following mode is entered, but the same program following command is issued by the user's button operation, etc. The present invention can also be applied when the same program following mode occurs.

Effects of the Invention As described above, in the RDS receiver control method of the present invention, when the same program follow-up command is issued due to deterioration of the reception condition of broadcast waves at the current receiving frequency, etc., the stored same network station Read out the AF data of the group sequentially and
Switch the reception frequency to the frequency given by the F data, check the reception signal level and PI data, and then switch the reception frequency to the frequency given by the F data.
A: The I data does not match the received broadcast wave data.
The F data is ignored and the reception frequency is switched to a frequency given only by other AF data to search for broadcast waves from the same network station with good reception conditions. Therefore, even if the AF data of the same network station group includes a frequency that is also used by another different network station, the AF data of the different network station is removed at an early stage, so you can watch the same program without feeling any discomfort. You can quickly switch to a broadcast wave that can be heard with good reception.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an RDS receiver to which the control method according to the present invention is applied, and FIG. 2 (ω. mountain) shows the control method according to the present invention executed by the processor in the controller shown in FIG. FIG. 3 is a flowchart showing the procedure, FIG. 3 is a diagram showing the baseband coding structure of a radio data signal, and FIG. 4 is a diagram showing the format of a type OA group. Explanation of symbols of main parts 2...Front end 4...FM detector 5...Multiplex demodulation circuit 8...
Digital PLL circuit 9... Decoder 14... Controller

Claims (1)

[Claims] When an RDS receiver capable of receiving RDS broadcast waves including program recognition data representing a network and equipped with a frequency data list of the same network station group receives a command to follow the same program, frequency data is sequentially read from the frequency data list. A readout step, a switching step for switching the reception frequency to the frequency given by the frequency data read in the readout step, and each time the reception frequency is switched in the switching step, the received signal level is equal to or higher than the set level and the signal is received. a determination step in which it is determined whether a broadcast wave whose program recognition data matches the broadcast wave that was previously received is received; A control method that includes a control step for stopping switching of reception frequencies in a switching step, wherein the determination result in the determination step is stored, and in the readout step, when frequency data reading has completed one cycle, program recognition is performed in the determination step. A control method characterized in that reading of frequency data determined to be inconsistent is stopped.