JPH03293820A - Channel selecting method for rds preset receiver - Google Patents

Abstract

PURPOSE:To resolve the contradictory feeling for channel selection by starting muting in response to a channel selecting command and releasing the muting at the time when the reception signal level is higher than a set level and coincides with stored corresponding PI data. CONSTITUTION:A controller 13 stores AF data indicating the reception frequency of a broadcast station, which is received at present, in a prescribed area of a memory 14 as AF data of one preset station and stores plural AF data of the same network station group as an AF list and stores PI data in a storage area corresponding to each preset station. When the channel selecting command is issued, muting is started; and when the reception signal level given by AF data of a designated preset station is higher than the set level or the reception signal level is higher than the set level by a network follower and obtained PI data coincides with preset PI data, muting is released. Thus, the contradictory feeling for channel selection is resolved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a preset receiver for a radio data system (
The present invention relates to a channel selection method for an RDS preset receiver (hereinafter referred to as an RDS preset 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 (Bjpha).
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 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, each block consisting of a 16 bit information word and a 10 bit check word. In addition, each group is classified into 16 types from 0 to 15 using 4 bits according to its contents, and each type (0 to 15) is classified into 16 types (A to 15).
, B are defined.

FIGS. 4(a) and 4(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. However, in block 4, broadcasting station name data (hereinafter abbreviated as PS data) is arranged. On the other hand, type OB group (b
), only the contents of block 3 are different from those of the type OA group, and block 3 has PI data arranged therein. 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 type OA group radio data signal 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 and PI data obtained by demodulation are captured and stored as an AF list, and if the reception sensitivity of the broadcasting station currently being received decreases due to disturbances such as multipath interference, for example, A who remembers
A so-called network follow (Network Follow) is used to check whether the program received according to the AF list is correct by selecting other stations in the same network station group based on the F list and then comparing the PI data to match. ) function allows
You can always listen to the same program with good reception without being affected by external disturbances.

By the way, the RDS preset receiver is equipped with a preset channel memory having a storage area corresponding to each of a plurality of preset stations, and each storage area of the preset channel memory stores AF data indicating the receiving frequency of each preset station. , multiple AF data (A
F list) and PI data are stored. and,
If you select one of the preset stations and the reception sensitivity is low, the A that corresponds to the preset station.
Network follow processing is performed based on the F list.

In this RDS preset receiver, when selecting a teleset station, conventionally, after entering the receiving state of the specified preset station, the received signal level is checked, and the network is started only when the received signal level is less than the set level. The process was supposed to be executed. Therefore, network follow processing is performed after noise or other sound is output, which may feel strange to the user, and also because the preset station is selected when the received signal level is higher than the set level. , a station with PI data different from the PI data preset in the preset channel memory may be received as is.

SUMMARY OF THE INVENTION [Object of the Invention] Therefore, the present invention provides an RDS station that eliminates the sense of incongruity when selecting a preset station, and also enables reception of an RDS station with the same PI data as the designated preset station when the designated preset station cannot be received. The purpose of this invention is to provide a channel selection method for a preset receiver.

[Structure of the Invention] A channel selection method according to the present invention includes a memory having a storage area corresponding to each of a plurality of preset stations, and in each storage area of this memory, AF data indicating the receiving frequency of each preset station, and each preset station are stored. A channel selection method for an RDS preset receiver in which a plurality of AP data and PI data of the same network station group superimposed on the station's broadcast waves are stored, the method comprising:
A first step of starting audio mute in response to a tuning command for any one of a plurality of preset stations, and AF data of the designated preset station at the time of the tuning command from the corresponding storage area of the memory. The preset station is an RDS station, the received signal level is equal to or higher than the set level, and the PI data obtained from the broadcast wave is stored in the memory. A second step in which audio muting is canceled when the signal matches the PI data, and an RDS in which the received signal level is equal to or higher than the set level and the PI data matches in this second step.
If not, select an RDS station with the reception frequency given by the plurality of AF data corresponding to the designated preset station, and select the RDS station whose reception signal level is equal to or higher than the set level and the PI data obtained from the broadcast wave is the same as above. It consists of a third step of canceling the audio mute when it matches the corresponding PI data stored in the memory.

[Operation of the invention] In the channel selection method according to the present invention, when there is a channel selection command for any one of a plurality of preset stations, audio muting is first started and the AF data of the designated preset station is given. When the reception frequency is set and the preset station is an RDS station and the reception signal level is above the set level and the PI data obtained from the broadcast wave matches the preset PI data, audio muting is canceled. , If the received signal level is higher than the set level and the PI data does not match the RDS station, RDS is performed based on the AF list corresponding to the designated preset station.
When a station is selected and the received signal level of the RDS station is higher than the set level and the PI data obtained from the broadcast wave matches the preset PI data, audio muting is canceled.

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 preset receiver to which a channel 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 controlled on and off by the controller 13.

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 pie-phase 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. 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.

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 inputs AF data indicating the reception frequency of the broadcasting station currently being received, which is read from data sequentially input in groups from the error correction circuit 12 by pressing a preset key 15a on the operation unit 15. 1 preset station AF
At the same time, multiple AF data of the same network station group superimposed on the broadcast wave is stored as an AF list, and PI data is stored in a storage area corresponding to each preset station. Also, any one of the preset station keys "1" to "6" to 15b
key When selecting a preset station manually, the AF data of the designated preset station is read from the corresponding storage area of the memory 14, and the front end 2 is loaded based on the AF data.
The programmable frequency divider (
The channel selection operation is performed by controlling the frequency division ratio (not shown), and if the specified preset station cannot be received due to poor reception conditions, it selects a station with good reception conditions based on the AF list corresponding to the preset station. Execute the network follow function to tune to the same network station.

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, the processing procedure for preset channel selection executed by the processor of the controller 13 will be explained with reference to the flowchart of FIG.

Note that this routine performs the steps “1” to “6” on the operation unit 15.
It is assumed that any one of the preset station keys 15b of ``1'' is called up and executed according to the manual preset station selection command of the key 1.

In response to the preset channel selection command, the processor first turns on the muting circuit 18 to mute the audio (step S1), and then reads out the AF data of the designated preset station from the corresponding storage area of the memory 14 and displays it on the front panel. The signal is output to the PLL circuit (not shown) at end 2 (step S2), and at the same time, a PLL timer is set for the time required for the PLL circuit to lock (step S3). The AF data supplied to the PLL circuit is set in a programmable frequency divider within the PLL circuit, so that the receiving frequency changes to the frequency of the designated preset station during the period until the PLL timer times up.

After the PLL timer times up (step S4), the processor determines whether the broadcast of the preset station is an RDS broadcast (step S5). If it is an RDS broadcast, the processor detects the received signal level Vs of the RDS station. The data is taken in from the circuit 16 (step S6). Whether or not it is an RDS broadcast can be determined by whether or not radio data can be taken in from the error correction circuit 12. Next, the processor determines that the captured received signal level Vs is the set level vt.
It is determined whether or not it is equal to or higher than the set level Vth (step S7), and if it is equal to or higher than the set level Vth, a PI timer for a predetermined time is set (step S8), and then the PI of the RDS station is
Data is taken in (step S9).

When the PI timer times up (step 510)
, the processor performs a PI check to see if the imported PI data matches the PI data preset in the memory 14 corresponding to the designated preset station (step 511), and if the PI data matches, teeth,
The muting circuit 18 is turned off to cancel audio muting (step 512). As a result, the RDS station whose reception signal level is equal to or higher than the set level vth and whose PI data is the same as the preset PI data is selected.

If it is determined in step S5 that it is not an RDS broadcast, if it is determined in step S7 that the received signal level Vs is less than the set level vth, or if it is determined in step S11 that the PI data do not match, the processor stores the specified information in the memory 14 in advance. Step 813) reads out AF data 1 in the AF list stored corresponding to the preset station, outputs this AF data to the PLL circuit step 514), and simultaneously sets the PLL timer (step 515).

After the PLL timer times up (step 516),
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 (step 517), and if the receiving station exists, the received signal level of the receiving station is determined. Import VS (step 81
8), it is determined whether the received signal level Vs is equal to or higher than the set level vth (step 519). If the received signal level Vs is higher than the set level vth, the process
Tsusa determines whether the broadcast of the receiving station is an RDS broadcast (step 520), and if it is an RDS broadcast, captures the PI data (step 521), and then presets the captured PI data and the memory 14. A PI check is performed to see if the PI data matches the current PI data (step 522).

If it is determined in step 517 that there is no receiving station, if it is determined in step S19 that the received signal level VS is less than the set level vth, or in step S22
If it is determined that the PI data do not match in step 524), the processor determines whether network follow processing has been completed for all of the AF list.
, if the process has not been completed, the process returns to step 913 and repeats the process described above. If it is determined in step S22 that the PI data match, the processor turns off the muting circuit 18 and cancels the audio mute (step 523).

Through this network follow processing, the RD of the receiving frequency given by any one of the AF data in the AF list is
S station, whose received signal level vs is the set level V
This means that a station has been selected which is equal to or greater than th and whose PI data obtained from the broadcast wave matches the preset PI data.

If it is determined in step S24 that network following has been completed for all of the AF list, the processor reads out the AF data of the currently designated preset station again from the corresponding storage area of the memory 14.Step 5
25) Output this AF data to the PLL circuit (Step 526), and at the same time set the PLL timer (Step S7). After the time has expired (Step 528), muting circuit 18 is turned off to cancel the audio NEET. (Step 529). to this.

P obtained from the emitted wave when the receiving subscriber level Vs is equal to or higher than the set level Vth by network follow processing based on the AP list corresponding to the specified preset station.
If the I data is preset and an RDS station that matches the PI data cannot be received, the designated preset station will be selected even if the reception condition is poor.

As described in detail, in the channel selection method according to the present invention,
When one of the multiple preset stations receives a tuning command, it first starts muting the audio, sets the receiving frequency given by the AF data of the designated preset station, and determines if the preset station is an RDS station. The received signal level is equal to or higher than the set level, and the P obtained from the broadcast wave is
When the I data matches the preset PI data, audio muting is canceled, and if the received signal level is higher than the set level and the PI data is not an RDS station that matches, the AF list corresponding to the specified preset station is PI that can be obtained from the broadcast wave when the received signal level is higher than the set level by network follow based on
R whose data matches the preset PI data
By canceling the audio minit when receiving a DS station, you can select an RDS station with better reception before canceling mute, which eliminates the problem of preset station selection due to noise etc. being output as in the past. In addition, when the designated preset station cannot be received, an RDS station having the same Pl data as the designated preset station can be received.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of an RDS preset receiver to which the tuning method according to the present invention is applied, and FIG. 2 shows the processing procedure for preset tuning, which is the tuning method according to the present invention. 8 is a flowchart, FIG. 3 is a diagram showing the baseband coding structure of radio data, and FIG. 4 is a diagram showing the format of group types OA (a) and OB (b). Explanation of the symbols of the main parts?・・・・・・Front end 4・・・・・・F
M detector 5...Multiplex demodulation circuit 8...
...Digital PLL circuit

Claims (2)

[Claims] (1) A memory having a storage area corresponding to each of a plurality of preset stations, and each storage area of this memory contains frequency data indicating the received frequency of each preset station, and the same frequency data that is superimposed on the broadcast wave of each preset station. R in which a plurality of frequency data and program identification data of a group of network stations are stored.
A tuning method for a DS preset receiver, comprising: a first step of starting audio mute in response to a tuning command for any one of the plurality of preset stations; and a specified preset at the time of the tuning command. Obtain the frequency data of the station from the corresponding storage area of the memory, set the receiving frequency given by the frequency data, and determine if the preset station is an RDS station, the received signal level is equal to or higher than the set level, and the receiving frequency is obtained from the broadcast wave. a second step of canceling the audio mute when the program identification data received matches the corresponding program identification data stored in the memory; If there is no matching RDS station, select the RDS station with the receiving frequency given by the plurality of frequency data corresponding to the specified preset station, and select that RD station.
and a third step of canceling the audio mute when the received signal level of the S station is higher than the set level and the program identification data obtained from the broadcast wave matches the corresponding program identification data stored in the memory. A channel selection method characterized by: (2) In the third step, if the received signal level is higher than the set level and there is no RDS station with matching program identification data, reset the receiving frequency given by the frequency data of the designated preset station and mute the audio. 2. The channel selection method according to claim 1, further comprising a fourth step of canceling the channel selection method.