JP2567433B2 - Radio data receiver control method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a receiver of a radio data system (hereinafter referred to as RDS).
(Referred to as a receiver).

BACKGROUND ART Broadcasting-related information such as information related to the program content is transmitted as data at the time of broadcasting from a broadcasting station by multiplex modulation, and the desired program content can be selected on the receiving side based on the demodulated data. In this way, a radio data system (RD that enables the service to be provided to radio listeners
S) there.

In this radio data system, 57KHz which is the third harmonic of the 19KHz stereo pilot signal outside the frequency band of the FM modulation wave is used as the subcarrier, and this 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 subcarrier is frequency-modulated to a main carrier for broadcasting.

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 consists of 4 blocks each having 26 bits, and each block consists of a 16-bit information word and a 10-bit check word. In FIG. 4, a block 1 is a program identification (PI) code representing a network, a block 2 is a traffic program identification (TP) code, and a block 3 is a station frequency of a network station broadcasting the same program ( AF) data and program service name information (PS) data such as a broadcasting station name and a network name are arranged in the block 4. In addition, each group is classified into 16 types of types 0 to 15 with 4 bits according to the content, and two versions A and B are defined for each type (0 to 15). Code is located in block 2. The station frequency of the network station (hereinafter AF
Data is transmitted only in the type 0A group, and program service name information (hereinafter abbreviated as PS) data is transmitted in the type 0A and 0B groups.

The TP code is arranged in the block 2 of each group, and is a 1-bit code indicating whether or not the broadcast wave transmits traffic information. That is, when the TP code is logic “0”, the broadcast wave does not transmit traffic information.
If the code is logic "1", it is a broadcast wave for transmitting traffic information. Normally, when a TP code of logic "1" is obtained from the received broadcast wave, a predetermined lamp is turned on in the receiver so that the listener can know.

By the way, when you come near the boundary of the network of the RDS broadcasting station while the vehicle is traveling, or when you enter the next network area, you can quickly switch to the RDS broadcast of the network that is broadcasting the traffic information of the future driving area and send the traffic information. It would be good if you could listen.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a control method of a radio data receiver capable of quickly selecting a radio data broadcasting station that sends out traffic information of a region in the traveling direction.

The radio data receiver control method of the present invention is capable of receiving radio data broadcast waves including a data signal that indicates at least the traffic number organization-specific information indicating whether the station is a broadcast station transmitting traffic information and the program recognition information. A method of controlling a radio data receiver, which is a holding process for reading and holding the program recognition information of the radio data broadcast wave currently being received, and starting a reception frequency sweep within the reception frequency band when a sweep mode is specified. Sweep process, and when a radio data broadcast wave is received in the sweep mode, it is detected from the traffic program identification information of the received radio data broadcast wave that the broadcast station is the transmission station of the traffic information, and the program of the received radio data broadcast wave is detected. A detection process for detecting a discrepancy between the recognition information and the program recognition information held in the holding process, and traffic information in the detection process. It is characterized by comprising a stop process to stop the sweeping operation in only sweep stroke when detecting each mismatches and that the program identification information is transmitted broadcasting station.

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

In the RDS receiver to which the control method of the present invention shown in FIG. 1 is applied, the FM multiplex broadcast wave received by the antenna 1 is converted to an intermediate frequency (IF) by selecting a desired station in the front end 2. FM detector 4 via IF amplifier 3
Is supplied to. The front end 2 converts the local oscillation signal to the mixer 2b into a P signal using a PLL circuit 2a including a programmable frequency divider.
It is obtained by the LL synthesizer method, and has a configuration in which a tuning operation is performed by controlling the frequency division ratio of the programmable frequency divider by a controller 14 described later.
The detection output of the FM detector 4 is supplied to the MPX (multiplex) demodulation circuit 5, and in the case of stereo broadcasting, L (left), R
It is separated into (right) channel audio signals.

Further, the detection output of the FM detector 4 passes through the filter 6, so that the 57 KHz subcarrier amplitude-modulated by the biphase-coded data signal, that is, the radio data signal is extracted and demodulated by the PLL circuit 7. . This demodulated output is the digital (D) PLL circuit 8 and the decoder 9.
Is supplied to. The D-PLL circuit 8 generates a data demodulation clock based on the demodulation output of the PLL 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 the lock detection signal to the gate circuit 10, and controls the circuit 10 to be in an open state. In the decoder 9, the bi-phase coded data signal which is the demodulated output of the PLL circuit 7 is decoded in synchronization with the clock generated in the D-PLL circuit 8.

As shown in FIG. 4, the output data of the decode 9 is a 104-bit group unit consisting of 4 blocks of 26-bit structure, and is sequentially supplied to the group, block synchronization & error detection circuit 12. In the group / block synchronization & error detection circuit 12, the group and block are synchronized based on the 10-bit offset word assigned to the 10-bit checkword of each block, and the 16-bit information is based on the checkword. Word error detection is performed. Then, the error-detected data is supplied to the controller 14 after the error is corrected by the error correction circuit 13 at the next stage.

The controller 14 is composed of a microcomputer, and code information of each block in the radio data that is sequentially input in units of groups, that is, radio data information related to the program content of the broadcasting station currently being received (the PI code and AF data described above). , PS data, etc.) and capture it in the memory 15. In addition, a sweep mode is set based on a sweep channel selection command from a sweep mode button (not shown) of the operation unit 16, and a programmable frequency divider (not shown) of the PLL circuit 2a forming a part of the front end 2 is set. The tuning operation is performed by controlling the received frequency data value that determines the division ratio. The reception frequency data value is, for example, the count value of the counter.

On the other hand, the station detection circuit 20 generates a station detection signal when the IF signal in the IF amplifier 3 is equal to or higher than a predetermined level and the detection output of the so-called S curve characteristic in the FM detector 4 is within the predetermined level range. The signal is supplied to the controller 14.

The memory 15 is composed of a nonvolatile RAM in which data such as reception frequency data, PI code, AF data, etc. is written, and a ROM in which programs and data are written in advance.

Next, a controller 14 showing the procedure of the control method of the present invention.
The operation of the processor will be described with reference to the flowchart shown in FIG.

When the processor detects the operation of the sweep mode button of the operation unit 16 and enters the sweep mode, it changes the reception frequency data value supplied from the controller 14 to the PLL circuit 2a of the front end 2 (step 51). Then, it is determined whether or not a predetermined time has elapsed after changing the reception frequency data value (step 52), and if the predetermined time has elapsed, it is determined whether or not a station detection signal is generated (step 53). In addition,
The predetermined time is a little longer than the time from when the reception frequency data value is changed to when the broadcast wave can be received until the station detection signal by the broadcast wave is obtained. As the reception frequency data value changes, the frequency division ratio of the frequency divider of the PLL circuit 2a changes at a predetermined step so that the reception frequency is, for example, 10
Increases by 0 KHz. When the broadcast wave cannot be received at this new reception frequency, the station detection signal is not generated, and therefore the process returns to step 51 and the reception frequency is changed again. Therefore,
When the broadcast wave cannot be received, the reception frequency changes every predetermined time. On the other hand, when a new broadcast wave is received, the IF signal level rises above a certain level and at the same time the FM with S-curve characteristics
When the detection output is within the specified level range, the station detection circuit 20
Generates a station detection signal. When this station detection signal is generated, the data supplied from the error correction circuit 13 is input (step 54), and it is determined whether or not the input data is obtained (step 55). If no input data is obtained, the received broadcast wave is not the RDS broadcast wave, and therefore the process proceeds to step 51 for further sweeping. When the input data is obtained, it is determined whether or not the content of the TP code of the input data is logical "1" (step 56). If the TP code = logic “0”, it is not an RDS broadcast wave that broadcasts traffic information, so the procedure returns to step 51 and the reception frequency is changed again. When the TP code = logical “1”, it means that the RDS broadcast wave broadcasting the traffic information is received, and the PI code is read from the input data (step 57). Next, the PI code of the RDS broadcast received before the sweep mode written in the memory 15 is read (step 58), and it is determined whether or not the two PI codes match (step 59). If the PI code matches, the RDS broadcast received before the sweep mode was received on the same network, so perform a step to further sweep.
Move to 51. On the other hand, if the PI codes do not match, the RDS broadcast received before the sweep mode is received on a different network, and the current reception frequency data value is held (step 60), and the sweep mode is ended. After the sweep mode ends, input data such as PI code and PS data is stored in the memory 15
Write in.

Immediately after entering the sweep mode, the PI code is read from the memory 15 and the controller 14 such as a buffer or register is read.
The input data such as the PI code and the PS data may be written in the memory 15 immediately after receiving the RDS broadcast by temporarily holding it in the internal memory.

As described above, in the control method of the radio data receiver according to the present invention, it is determined that the broadcast station transmits the traffic information based on the traffic program identification information TP obtained from the radio data broadcast wave received by the sweep operation. However, the sweep operation is stopped only when the program recognition information PI is different from the program recognition information immediately before the start of the sweep operation, so when the vehicle is running near the boundary of the network of the radio data broadcasting station or in the next network area. It is preferable that a radio data broadcasting station of the network that broadcasts traffic information in the traveling direction can be quickly selected when entering.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an RDS receiver to which the control method of the present invention is applied, FIG. 2 is a flow chart showing an operation of a processor in a controller in the receiver of FIG. 1, and FIG. 3 is a radio. FIG. 4 is a diagram showing a baseband coding structure of a data signal, and FIG. 4 is a diagram showing a format of a type 0A group. Explanation of symbols of main parts 1 ... Antenna 2 ... Front end 4 ... FM detector 5 ... Multiplex demodulation circuit 8 ... Digital PLL circuit 9 ... Decoder, 14 ... Controller 20 ... Station detection circuit

Claims (1)

(57) [Claims] 1. A method of controlling a radio data receiver capable of receiving a radio data broadcast wave including a data signal indicating at least traffic program identification information and program recognition information indicating whether or not the station is a broadcasting station transmitting traffic information. In the sweep mode, the holding process that reads and holds the program recognition information of the radio data broadcast wave that is currently being received, the sweep process that starts the sweep of the reception frequency within the reception frequency band when the sweep mode is specified, and the sweep mode When a radio data broadcast wave is received, it is detected from the traffic program identification information of the received radio data broadcast wave that it is the broadcasting station of the transmission of the traffic information, and the program recognition information of the received radio data broadcast wave and the holding process are held. A detection process for detecting a discrepancy with the recognized program recognition information, and a broadcasting station that sends traffic information in the detection process. And a stop step of stopping the sweep operation in the sweep step only when each of the mismatches of the program recognition information is detected, and a control method of the radio data receiver.