JPH01149527A - Rds receiver control method - Google Patents

Abstract

PURPOSE:To cause a receiving condition to be satisfactory by, when the same network station frequency at a receiving level larger than the receiving signal level of a present receiving frequency exists, making the station frequency into a new receiving frequency. CONSTITUTION:Each time a fixed time passes, the receiving signal level of the present receiving frequency and the receiving signal levels of the other network station frequencies given by AF data fetched in a memory 15 are compared by means of a controller 14. Since, when the network station frequency at the level of the receiving signal larger than the receiving signal level of the present receiving frequency exists, the network station frequency is made into the new receiving frequency, the broadcasting program of the same network can be always listened to in a more satisfactory receiving condition.

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.
57, which is the harmonic, has a subcarrier of Hz, and this subcarrier is filtered and biphase (Bl) h
a.e.) A 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. There is.

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, and each block consists of a 16 bit information word and a 10 bit check word. In Figure 5, block 1 contains the program recognition (PI) code representing the network, block 2 contains the traffic program recognition (TP) code and traffic announcement recognition (TA) code, and block 3 contains the program recognition (PI) code that represents the network, and block 3 contains the program recognition (PI) code that represents the network. The frequency of the network station group (AF
) data, and block 4 contains program service name information (PS) data such as broadcasting station name, network name, etc. Furthermore, each group is classified into 16 types, 0 to 15, using 4 bits according to its content, and two versions, A and H, are defined for each type (0 to 15), and these The recognition code is placed in block 2. In addition, network station A
F data is transmitted only in type OA groups, and PS data is transmitted in type OA and OB groups.

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.

However, in the case of RDS broadcasting, as mentioned above, when one RDS broadcast wave is received, it is possible to obtain the AF data of a group of network stations broadcasting the same program, so this AP data can be used to improve the received signal level. It is possible to select another same network station with a higher electric field strength.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of controlling an RDS receiver that allows broadcast programs on the same network to be always listened to in better reception conditions.

A method for controlling an RDS receiver according to the present invention is to take in the AF data obtained by demodulating the received broadcast waves in an RDS receiver capable of receiving RDS broadcast waves including AF data of the same network station group, and after a certain period of time has elapsed. At each time, the received signal level of the current received frequency is compared with the received signal level of other same network station frequencies given by AF data, and the received signal level of the same network station frequency is higher than the received signal level of the current received frequency. is present, the same network station frequency is set as the new reception frequency.

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

In FIG. 1, which shows an example of the configuration of an RDS receiver to which the control method according to the present invention is applied, the front end 2 selects a desired station for the FM multiplex broadcast waves received by the antenna 1, and the intermediate frequency (!F ), the IF amplifier 3
The signal is supplied to the 1M detector 4 via the 1M 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 1M detector 4 is supplied to an MPX (multiplex) demodulation circuit 5, and in the case of stereo broadcasting, L(
(left) and R (right) channel audio signals.

Furthermore, when the detection output of the 1M detector 4 passes through the filter 6, a 57 KHz subcarrier amplitude-modulated by the pie-phase 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. 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. The lock detection signal is also supplied to the AND circuit 17 as a synchronization detection signal indicating that synchronized demodulated data is obtained. In decoder 9, P
A biphase coded data signal, which is the demodulated output of the LL circuit 7, is decoded in synchronization with the clock generated by the D-PLL circuit 8.

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 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
code, AF data, PS data, etc.) and store it 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). The received frequency data value is, for example, a count value of a counter.

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.

Note that the memory 15 stores AF data obtained by demodulating received broadcast waves, and stores AF data lists f, f2, . . . of the same network stations as the broadcast station currently being received.
- It is assumed that fn has already been created.

The processor detects that a same program follow button (not shown) on the operation unit 16 has been operated, detects a tuned state by receiving a station detection signal from the station detection circuit 18, or detects power-on. Start a timer for a predetermined time T at the time when
1, it is monitored whether or not this timer has timed up. When the time up of the timer is detected (step S1), the received signal level vO of the current received frequency fD supplied from the level detection circuit 17 and the PI code representing the network of the receiving station are fetched and stored in the memory 15 (step S2), and then 1 in the list is read out from the memory 15 according to the AF data list and set in the programmable frequency divider of the PLL circuit in the front end 2, thereby changing the reception frequency from the current reception frequency fD to another network station frequency fS. (Step S3). Then, the level detection circuit 17 detects the received signal level Vs of this network station frequency fS.
(step S4), and this received signal level V
It is determined whether or not s is greater than the received signal level VD stored in the memory 15 (step S5). If the received signal level VS is less than the received signal level VD, AF
It is determined whether or not the reception signal levels of all network station frequencies given by the data list have been checked (step S6). If not, step S6) is performed.
3, the next AF data is read from the memory 15 according to the AF data list.

The above operation is performed in step S5 with the reception signal level V
The process is repeated until it is determined that s is greater than the received signal level vO, or it is determined in step S6 that the received signal levels of all network station frequencies have been checked.

If it is determined in step S6 that the received signal levels of all network station frequencies have been checked,
Since there was no network station frequency with a received signal level greater than the received signal level vl of the current received frequency fD, the response is to return the received frequency to the original received frequency at which it started, that is, the current received frequency fD. AF
Data is read from the memory 15 and set in the programmable frequency divider (step S7). Then, in step S, it is determined whether the PI code obtained from the received broadcast wave matches the PI code stored in the memory 15.
8) If they match, set the previous timer in step S9), and then shift to normal reception mode. on the other hand,
If it is determined in step S5 that the received signal level Vs is higher than the received signal level Vo, this means that there is a network station frequency with a received signal level higher than the received signal level VO of the current received frequency fo. from,
After confirming that the PI codes match in step S8, the network station frequency is set as a new receiving frequency. Then, set the timer in step S.
9) After that, it shifts to the normal reception mode. The series of operations described above is repeated every time the fixed time T given by the timer elapses.

In this way, every time a certain period of time (T) elapses, the received signal level of the current received frequency is compared with the received signal level of other network station frequencies given by the AF data stored in the memory 15, and the received signal level of the current received frequency is determined. When there is a network station frequency with a received signal level higher than the received signal level of Become.

In the above embodiment, the network station frequency with the received signal level that is even slightly higher than the current received frequency is set as the new receiving frequency, but the network station frequency with the highest received signal level among all network stations is set as the new receiving frequency. It is also possible to set this as a new reception frequency, and according to this,
This means that you can always listen to broadcast programs from the same network in the best reception condition. A flowchart showing the procedure in this case is shown in FIG. In the figure, in step S2a, the received signal level is paired with AF data and stored in the memory 15, and in step S3, the received frequency is switched in order according to the AF data list every time this step is passed, and reception of each network station frequency is performed. Check signal level in state S3. S4) If it is determined in step S5 that the received signal level is higher than the previous time, the received signal level and AP data in the memory 15 are updated to the current ones. By repeating this operation until it is determined in step S6 that the received signal levels of all network station frequencies have been checked, the memory 15 stores the maximum received signal level among all network stations and the AF data of that network station. will remain.

Therefore, by reading this AF data from the memory 15 and setting it in the programmable frequency divider, the network station frequency with the highest received signal level among all network stations can be set as the new receiving frequency. .

In each of the above embodiments, the AF data obtained by demodulating the received broadcast waves is taken in and stored in the memory 15. However, since the AF data is repeatedly sent, it is not necessarily stored in the memory 15. There is no need to remember it, A
It is also possible to import the F data when necessary.

As described in detail of the invention, according to the RDS receiver control method according to the present invention, the reception signal level of the current reception frequency and the reception signal of another same network station frequency given by the AF data are determined every predetermined period of time. If there is a same network station frequency with a received signal level higher than the received signal level of the current received frequency, this same network station frequency is set as the new received frequency, so the broadcast programs of the same network are This means that you can always listen with better reception conditions.

[Brief explanation of the drawing]

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

Claims (2)

[Claims] (1) RD containing frequency data of the same network station group
A control method for an RDS receiver capable of receiving S broadcast waves, wherein the frequency data obtained by demodulating the received broadcast waves is taken in, and every certain period of time, the received signal level of the current reception frequency and the frequency data are controlled. Compare the received signal level of the same network station frequency with the received signal level of other same network station frequencies, and if there is a same network station frequency with a received signal level higher than the received signal level of the current received frequency, select this same network station frequency as a new reception signal level. A method for controlling an RDS receiver, characterized in that the frequency is set as a frequency. (2) The RD according to claim 1, characterized in that the new reception frequency is set to the reception frequency with the highest level among the reception signal levels of all the same network station frequencies.
How to control the S receiver.