JPH02213229A - Automatic tracking method for radio data system - Google Patents

Abstract

PURPOSE:To continue automatic tracking by receiving a PTY station sending one and same PTY code based on a genre identification code PTY included in a transmission data when one and same PI station cannot be received even after being sought for a prescribed time. CONSTITUTION:When an optional broadcast station is selected and a radio data system(RDS) code is superimposed, a main microcomputer 11 reads a PI code or a PTY code or the like in a built-in memory, and the main microcomputer 11 applies conventional up-search or down-search intermittently, searches the same PI station with an excellent reception level while confirming the signal intensity by a signal meter 9 and when the same PI station is not searched, the automatic tracking of the same PI station is switched into the automatic tracking of the PTY station, down-search or up-search is implemented intermittently, a broadcast station having the same PTY code as the initial reception station receives a broadcast station (PTY station) with an excellent reception level to make the processing complete.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is based on the program identification code PI included in the transmission data of RDS (Radio Data System).
Regarding the automatic tracking method of RDS that receives the broadcasting station that is transmitting the I code, especially when the same PI station cannot be received, the PTY that is transmitting the same PTY code based on the genre identification code PTY instead of the PI code. receive a station,
The present invention relates to an RDS automatic tracking method that allows continuous automatic tracking.

<Prior art> Car radios are usually operated by the driver.
There has been a demand for more sophisticated single-channel selection functions, such as the need for re-selection each time a car travels a long distance and leaves the service area of a receiving station. This demand was particularly strong in Europe, where radio broadcasting services mainly consist of FM broadcasting, which has a relatively narrow service area, and where a high proportion of broadcasts are received on car radios. The data system standardized by the European Broadcasting Union to meet this requirement is RDS (Radio Data System).

RDS is a method that multiplexes various digital data (data that can be used for automatic selection of the best receiving station, traffic information identification, broadcasting station name display, etc.) on FM radio broadcasts, and some of these transmitted data include AF code, PI code, PT
There are Y codes etc.

The AF code is called an alternative frequency code and corresponds to the frequency code of a broadcasting station (AF station) that broadcasts the same program in the same or adjacent reception area. All frequencies are now visible. The 5PI code is also called a program identification code, and is a unique code given to a broadcast program. The PTY code is called a genre identification code and is a code for identifying the genre of a broadcast program, and has a separate code for each genre such as classical, rock, popular, and news.

Conventionally, for example, when automatically following the same program,
Based on the above-mentioned PI code, the signal strength (for example, electric field strength) of the broadcasting station currently being received is compared with the electric field strength of the broadcasting station transmitting the same PI.

The receiving station was automatically changed one after another to a broadcasting station with a stronger electric field strength than the current receiving station.

<Problem to be solved by the invention> However, in the conventional automatic tracking method using PI codes as described above, PI codes are not always completely unified in all of Europe or even within the same country. This is the result of the fact that in countries such as West Germany, the same program may be broadcast in different areas with different PI codes.

If you leave the original broadcast area, the same PI code cannot be detected and automatic tracking ends, causing problems such as only noise being output as audio until the same PI code is detected. there were.

From the above, an object of the present invention is to receive a PTY station transmitting the same PTY code based on the genre identification code PTY instead of the PI code when the same PI station cannot be received, and to continue automatic tracking. An object of the present invention is to provide an automatic tracking method for RDS.

Means for Solving the Problems The present invention solves the above problems by providing a means for recognizing that the broadcasting area has changed when the same PI station cannot be received even after searching for a predetermined period of time, and a means for recognizing that the broadcasting area change is recognized. This is achieved by means for receiving PTY stations transmitting the same PTY based on the genre identification code PTY included in the transmission data of the receiving station.

Function> If the same PI station cannot be received even after searching for a predetermined time, a PTY station transmitting the same PTY code is received based on the genre identification code PTY included in the transmission data.

<Embodiment> FIG. 1 is a block diagram of the main parts of a radio data system receiver that implements the automatic tracking method according to the present invention.

Reference numeral 1 denotes a PLL circuit, which outputs a predetermined voltage signal according to the station to be received to the FM front end 2. The FM front end 2 receives broadcast stations input from the antenna ANT based on voltage signals.

A predetermined intermediate frequency signal (IF) is generated. 3 is an intermediate frequency amplifier, which amplifies the intermediate frequency signal converted by the FM front end 2 to a predetermined level. 4 is M
PX demodulates the intermediate frequency signal input from the intermediate frequency amplifier 3 into a stereo signal. 5 is an amplifier (AMP
), and amplifies the stereo signal according to a volume setting value (not shown). A speaker 6 is driven by the amplifier 5 and outputs an audio signal corresponding to the stereo signal.

Reference numeral 7 denotes an RDS decoder, which demodulates the PI code, PTY code, etc. sent at predetermined transmission timing. 8
is an error correction circuit, which detects errors in RDS data such as PI code and PTY code demodulated by the RDS decoder 7 while synchronizing each group, and corrects the errors.

Reference numeral 9 denotes a signal meter, which monitors the signal strength (for example, electric field strength) of the intermediate frequency signal output from the intermediate frequency amplifier 3 to monitor the receiving stations (including PI stations and PTY stations).
Detects the level of reception status. 10 is a timer;
When automatically following a PI station.

The maximum time for searching 21 stations is defined as, for example, about 1 minute.

11 is the main microcomputer that controls the overall operation of the radio data system receiver, during automatic tracking.

Compare the signal strength of the receiving station and the signal strength of the PI station based on the detection level of the signal meter 9, and select a P with good reception condition.
means for searching for an I station; means for recognizing that the broadcasting area has changed if the PI station cannot be received within the time specified by the timer 10; Genre identification code P included in
It has means for receiving PTY stations transmitting the same PTY based on the TY.

The main microcomputer 11 obtains the PI code, PTY code, etc. during the same program broadcast that is sent superimposed on the received broadcast signal via the RDS decoder 7 and the error correction circuit 8, and when the reception condition becomes bad. Automatic tracking control is performed using the PI code or PTY code. In addition,
When performing automatic tracking, first search for a broadcasting station (PI station) with good reception that is broadcasting a program with the same PI code for a predetermined period of time, and then search within that time. If this is not possible, select a broadcasting station with good reception (PTY station) that broadcasts programs with the same PTY code.
Search for and switch to the searched receiving station. however,
In this case, the broadcast is interrupted for a short time that does not cause any discomfort.

The first step is as follows according to the flowchart of the process of the present invention shown in FIG.
The operation of the diagram will be explained.

When an arbitrary broadcasting station is selected (step 101), the main microcomputer 11 controls the RDS decoder 7 and the error correction circuit 8.
The main microcomputer 11 checks whether an RDS code such as a PI code or PTY code is superimposed on the received broadcast signal (step 102). If an RDS code is superimposed, the main microcomputer 11 The information is read into the built-in memory (step 103), and the signal strength of the received broadcast is monitored by the signal meter 9 (step 104).

When the signal strength of the received broadcast falls below a predetermined level, the main microcomputer 11 searches for a broadcast station with a strong signal strength (PI station) among the broadcast stations broadcasting programs with the same PI code, and also calculates the elapsed time. Start timing (step 1)
05).

In such automatic tracking, the main microcomputer 11 intermittently performs a normal up search or down search to search for the same PI station with a good reception level while checking the signal strength measured by the signal meter 9 (step 106).
When the same PI station is searched, the corresponding PI station is received (step 107).

On the other hand, if the same PI station is not searched as determined in step 106, the search for the PI station is continued until the timer 10 times up (step 108). After the time-up, the main microcomputer 11 recognizes that the broadcast area has changed. Step 109), and switch from automatic tracking of the same PI station to automatic tracking of PTY stations (step 110)
.

Step 11: Perform a down search or up search intermittently to receive a broadcast station (PTY station) with a good reception level from a broadcast station that has the same PTY code as the original receiving station.
1) End the process.

Further, if it is determined in step 102 that no RDS code has been transmitted, the process ends.

In the above embodiment, a receiver with a one-tuner configuration is illustrated in which the automatic tracking according to the present invention interrupts the broadcast currently being received and is performed in a short period of time that does not cause discomfort, but a receiver with a two-tuner configuration is illustrated. It goes without saying that the present invention can be carried out even if there is such a case.

Furthermore, according to the present invention, after a PTY station is received, the normal automatic tracking operation for the PI station is resumed.

<Effects of the Invention> According to the present invention, if the same PI station cannot be received even after searching for a predetermined time, a PTY station transmitting the same PTY code is received based on the genre identification code PTY included in the transmission data. Even if the same PI station cannot be received, the P that is transmitting the same PTY code
It has the excellent advantage of being able to receive TY stations and continue automatic tracking.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of a radio data system receiver that implements the automatic tracking method according to the present invention. FIG. 2 is a flowchart of the process of the present invention. 1..PLL circuit, 2..FM front end. 3. Intermediate frequency amplifier, 7. RDS decoder. 8...Error correction circuit. 9. Signal meter, 10. Timer, 11. Main microcomputer.

Claims (1)

[Claims] An RDS automatic tracking method for receiving broadcasting stations transmitting the same PI code based on a program identification code PI included in transmission data of a radio data system, comprising: searching for the PI station for a predetermined period of time; If the same PTY station cannot be received, a PTY station transmitting the same PTY code is received based on the genre identification code PTY included in the transmission data.