JP2525925B2 - RDS radio receiver tracking method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a tracking method of an RDS radio receiver, and particularly to a PI method.
The present invention relates to a tracking method of an RDS radio receiver when data is not detected, or when detected, it does not match the PI data of the original receiving broadcast station.

<Prior Art> RDS (radio data system) has been put to practical use in Europe, where FM broadcasting, which has a relatively small service area, is the main body of radio broadcasting services, and the ratio of broadcast reception by car radio is high. This RDS is a method that superimposes various digital data on an FM radio broadcast signal, and as a message, (i) program identification data (PI data) of the currently received FM broadcast (ii) broadcast station name data (PS (Iii) Frequency list (AF list) of broadcasting stations broadcasting the same program (iv) Program content identification data (PTY) (v) Transmission status identification data (DI) (vi) Music or conversation identification data ( M / S data) (vii) Traffic information broadcasting station identification data (TP data) (viii) Traffic information broadcasting identification data (TA data).

In this way, in RDS, the message (RDS data) related to the FM broadcast being received is transmitted in multiplex,
By using the message, an exceptional tuning operation that has never been possible becomes possible.

For example, if the automatic tracking on / off key is turned on, the frequency list (AF list) of the same program broadcasting station is demodulated, and the stations of the frequencies on the AF list (called AF stations) are demodulated.
It tunes to the frequency of the AF station with the maximum received electric field strength, which is higher than the received electric field strength of the receiving station up to that point (automatic tracking). In automatic tracking, the reception field strength of the AF station (referred to as AF search) is tuned to the AF station frequency for about 10 msec at 2.5 second intervals for each station so that no discomfort occurs. During that time, it is performed by muting.

By the way, what is on the AF list is actually RDS
You may not be broadcasting. Also, in countries such as France and Italy, there are many stations with the same frequency, and the PI data is often different. For this reason, conventionally, it is determined whether PI data is detected from the AF station with the maximum received electric field strength obtained by the AF search (called the maximum AF station). It checks whether it matches the PI data of the receiving broadcasting station, and if it matches, continues receiving from the maximum AF station, and if PI data is not detected, or the detected PI data is the PI of the original receiving broadcasting station. If it does not match the data, the AF station with the next highest received field strength is set as the maximum AF station to receive the broadcast, and the PI data that matches the PI data of the original receiving broadcast station is transmitted.
A station is sought and a broadcast from the AF station is received.

<Problems to be solved by the invention> The identity of PI data is confirmed after the PI data is extracted in synchronization with the maximum AF station. For this reason, if PI data is not detected, or if the PI data is different, it means that tuning is continued to the wrong AF station until the judgment is completed, and a program different from the program of the original receiving broadcast station is It will be broadcast and will give the user an unpleasant feeling.

From the above, the object of the present invention is to reduce the probability of receiving different programs during automatic tracking.
It is to provide a tracking method for an S radio receiver.

<Means for Solving the Problems> In the present invention, the above-mentioned problems are obtained by matching detected PI data.
A mismatch discriminating unit, a first marking means for performing a first marking on a predetermined AF station frequency in the PI reception status list when the detected PI data does not match the original PI data, and the AF
A counting unit that counts up the number of markings according to the station frequency, a marking releasing unit that releases the first marking after a predetermined time has passed, and a second marking that performs the second marking when the number of markings reaches a set number. Department,
This is achieved by a tuning controller that does not tune to the AF station where the first or second marking is performed.

<Operation> When PI data is not detected from the broadcasting station (maximum AF station) with the maximum received field strength obtained by AF search, or when the detected PI data does not match the PI data of the original receiving broadcasting station, The frequency of the maximum AF station in the PI reception status list created corresponding to the AF frequency in the AF list
When the number of markings according to the AF frequency is counted up and the first marking is released after a lapse of a predetermined time, and the number of markings at the predetermined AF station frequency reaches the set number, the PI reception status A second marking is performed on the AF station frequency in the list, and when determining the identity of PI data, the AF station with the first or second marking is not tuned.

<Embodiment> FIG. 1 is a block diagram of an essential part of an RDS radio receiver according to the present invention.

1 is an antenna, 2 is a front end, which will be described later.
An intermediate frequency signal (IF) is generated by tuning to a predetermined broadcasting station based on the voltage signal output from the PLL circuit. 3 is an intermediate frequency amplifier, 4 is a stereo demodulation circuit (MPX), 5 is a mute circuit, 6 is an amplifier (AMP), and 7 is a speaker.

Reference numeral 8 is a 57 KHz band pass (BPF), which passes a 57 KHz subcarrier amplitude-modulated based on the RDS data. An RDS decoder 9 demodulates the AF list, PI data, etc. from the output of the bandpass filter. 10 is an error correction circuit, which is the AF data demodulated by the RDS decoder 9,
Detects errors in RDS data such as PI data while synchronizing each group and corrects the errors.

A signal meter 11 monitors the received electric field strength using the intermediate frequency signal output from the intermediate frequency amplifier 3. Reference numeral 12 denotes a station detector, which determines that the receiving station exists when the received signal is within the frequency deviation Δf (bandwidth) of the received signal and the signal strength is equal to or higher than a predetermined level. Therefore, when the station detect signal SD is at a low level, even if the signal strength detected by the signal meter 11 is large, the broadcasting station at the tuning point does not actually exist, and the detected signal strength is influenced by the adjacent stations. Judge that you are receiving. Reference numeral 13 is an RDS that detects whether the receiving station is an RDS station based on the presence or absence of the output of the bandpass filter 8.
It is a station detection circuit. A PI data detection circuit that detects the presence or absence of PI data may be provided instead of the RDS station detection circuit 18.

Reference numeral 14 denotes a microcomputer-configured RDS controller that performs automatic tuning processing, which will be described later, based on RDS data, signal meter output, station detector output, etc., and also performs digital tuning processing. Processor 14a, program memory (ROM) 14b, data memory It has (RAM) 14c.

In the data memory 14c, the PI reception status list PIL shown in FIG. 2 is created for each AF list that has been received, corresponding to the AF station frequencies AF1 to AFn. , The number of markings m is written. If the PI data of the AF station is not detected, or if the detected PI data does not match the PI data of the original receiving broadcast station, the PI reception status The first marking is performed on the frequency of the AF station in the list PIL, the marking time tm is stored, and the marking count m is updated (counted up) according to the AF station frequency. Further, (b) the first marking and the marking time are released after a predetermined time has passed,
(C) Marking frequency m of the specified AF station frequency is set number M
Then, a second marking is made on the AF station frequency, and the second marking is not released until the power is turned off (ACC AF). However, marking is performed by writing "1".

15 is an operation panel, 15a is an operation unit, 15b is a display unit, 16 is an RD
It is a PLL circuit that inputs a voltage signal corresponding to the reception frequency data FDT input from the S controller to the front end 2 to tune to a predetermined broadcasting station.

The follow-up process of the present invention will be described below with reference to the flowchart of FIG.

In the automatic tracking process, the RDS controller 14 first receives the RDS data transmitted by being superimposed on the FM broadcast of the current receiving station through the bandpass filter 8, the RDS decoder 9 and the error correction circuit 10 (step 101). ).

Next, the RDS controller 14 detects the AF included in the RDS data.
The i-th AF station frequency is calculated from the list (the initial value of i is 1), and the AF station search processing of 10 msec is executed for the i-th AF station. That is, the mute command MUT is output to the mute circuit 5 to mute the sound, the PLL circuit 16 is instructed to receive the i-th AF station, and the front end 2 is tuned to the AF station frequency (step 102).

When the output signal SD of the station detector 12 is at a high level in the state of being tuned to the i-th AF station (step 103), if it is at a high level, there is a receiving station, so the signal output from the signal meter 11 is received. The electric field strengths are taken in and the received electric field strengths of the AF stations that have been taken in are sorted in descending order (step 104). Then, or if the signal SD is low level in step 103, it is checked whether or not the AF search is completed for the AF stations in all AF lists (step 105). If not, i +
1 → i is incremented by 1 (step 106), the mute is released, the receiving station is returned to the original receiving station, and the i-th
The search for the AF station is completed (step 107).

After that, it is checked whether the AF station search cycle (for example, 2.5 seconds) has elapsed (step 108), and if so, step 102
And repeats the subsequent processing.

When the AF search process is completed for all AF stations,
The received electric field strength level La of the original receiving station is compared with the maximum received electric field strength level Lm of the AF station (step 109). If La ≧ Lm, there is no need to change the receiving station, so return to the original receiving station (step 109). 110) End the automatic tracking process.

However, if La <Lm, the RDS controller refers to the PI reception status list to check if the AF frequency of the AF station with the maximum received field strength (maximum AF station) has secondary marking (step 111). If it is not marked next, it is checked whether it is marked next by referring to the PI reception status list (step 112).

If not primary marked, the controller 14
The PLL circuit 16 is instructed to receive the AF station having the maximum received electric field strength, and the front end 2 is tuned to the broadcasting frequency of the AF station (maximum AF station frequency) (step 113).

Then, based on the output of the RDS detection circuit 13, the receiving station
It is checked whether it is a station (step 114). In addition, this RDS
Checking whether a station is the same as checking whether PI data is detected or not. Therefore, instead of checking whether it is an RDS station, it may be checked whether PI data is detected from the RDS decoder 9.

If the PI data is detected at the RDS station, the PI data included in the RDS data sent superimposed on the FM signal is extracted, and the PI data is the name of the broadcast program broadcast by any receiving station. Is checked (step 115), and if they match, the reception of the currently received maximum AF station is continued and the automatic tracking processing routine is ended.

However, if the PI data is not detected, or if the detected PI data does not match the PI data of the original broadcasting station even if it is detected, the maximum AF station frequency in the PI reception status list is primarily marked and the marking time tm Is stored and the number of markings according to the maximum AF station frequency is m + 1 → m
To update (steps 116 and 117).

Then, it is checked whether the marking number m is equal to the set number M (step 118), and if m = M, secondary marking is performed on the maximum AF station frequency in the PI reception status list (step 119).

After that, or if the number of markings has not reached M, it is checked whether there is an AF station with the next largest received electric field strength (step 120).
Since there is no station, the reception frequency is returned to the broadcast frequency of the original reception station (step 121), and the automatic tracking process is ended.

If there is an AF station with the next highest received field strength, the AF station is regarded as the AF station with the maximum received field strength (step 122),
The processing after step 109 is repeated.

On the other hand, when the secondary marking is performed in step 111, the steps from step 112 to step 119 are skipped, that is, the PI data identity determination processing is skipped, and thus the secondary marking is performed.
Do not tune to the AF station. Therefore, if the PI data is not detected many times, or if the PI data is different and the secondary marking is performed, it is considered that the AF list is incorrect, and the PI data is judged to be the same. Therefore, it is possible to prevent the AF station frequency from being tuned, and it is possible to reduce a situation in which a program different from the program of the original receiving broadcast station is broadcast and gives an unpleasant feeling.

If the primary marking is made in step 112, it is checked whether the elapsed time (ta-tm) from the primary marking time of the AF station frequency to the current time exceeds the set time Ts (step 123). Then, clear the primary marking and marking time tm (Step 12
4) After that, the processing from step 113 onward is performed.

As a result, when determining the identity of PI data in the previous automatic tracking process, the reception status temporarily deteriorates, or a failure occurs and PI data is not detected, or PI data is not detected.
Even if the data does not match and the primary marking is made (step 114 to step 116), if it becomes the maximum AF station this time, it becomes possible to tune to determine the identity.

If the elapsed time does not exceed the set time in step 123, the steps from step 113 to step 119 are skipped, that is, the PI data identity determination processing is skipped, and the AF station on which the primary marking is performed is skipped. Try not to synchronize.

<Effects of the Invention> As described above, according to the present invention, PI data is not detected many times,
Alternatively, if the PI data is different many times (when the secondary marking is made), it is considered as "the AF list is wrong", and then the AF station frequency is changed to determine the identity of the PI data. It is possible not to synchronize with each other, and it is possible to reduce a situation in which a program different from the program of the original receiving broadcasting station is broadcast to cause discomfort.

Further, according to the present invention, the PI in the previous automatic tracking process is
Even if the reception status is temporarily deteriorated or PI data is not detected due to a failure at the time of determining the data identity, or PI data cannot be matched and primary marking is performed (step 114 to step 116) It can be relieved, and if it becomes the maximum AF station this time, it will be possible to tune to the maximum AF station.

[Brief description of drawings]

FIG. 1 is a block diagram of an RDS radio receiver according to the present invention, FIG. 2 is an example of a PI reception status list, and FIG. 3 is a flow chart of automatic tracking processing according to the present invention. 2 …… FM front end 9 …… RDS decoder 13 …… RDS station detection circuit 14 …… RDS controller

Claims (1)

(57) [Claims] 1. An RDS sent superimposed on an FM broadcast signal.
Check the received field strength of the AF stations included in the AF list included in the data, receive the broadcast from the AF station with the maximum received field strength that is higher than the received field strength of the original receiving broadcast station, and then , Determine whether the PI data of the maximum AF station is detected, and if PI data is detected, determine whether the PI data matches the PI data of the original receiving broadcast station,
If the detected PI data matches the PI data of the original receiving broadcast station, reception from the maximum AF station continues, and if PI data is not detected, or if the detected PI data is the original receiving broadcast station
If it does not match the PI data, the AF station with the next highest received field strength is set as the maximum AF station to receive the broadcast, and the AF station that transmits the PI data that matches the PI data of the original receiving broadcast station is obtained. In a tracking method of an RDS radio receiver having an automatic tracking function for receiving a broadcast from the AF station, a PI reception status list is created corresponding to the AF station frequency of the received AF list, and the PI data is not detected If or even detected
If the PI data does not match the PI data of the original receiving broadcast station, the first AF station frequency in the PI reception status list is marked first and the number of markings corresponding to the maximum AF station frequency is counted up. Then, the first marking is released after a lapse of a predetermined time, and when the number of markings of a predetermined AF station frequency reaches a set number, a second marking is performed on the AF station frequency of the PI reception status list. A method for following an RDS radio receiver, which is characterized in that when determining the identity of data, the AF station with the first or second marking is not tuned.