JPH0738595B2 - RDS receiver - Google Patents

Description

The present invention relates to a radio data system (RDS) receiver implemented in Europe.

[Conventional technology]

Generally, at the time of broadcasting at a broadcasting station, information related to the program content is transmitted as data by multiple modulation, and the receiving side can select the desired program content based on the demodulated data, so that the radio listener can There is a system RDS that makes it possible to provide that service to. This RDS data includes network identification code (PI), traffic information station identification code (TP), traffic announcement recognition code (TA), program service name information code (PS) such as broadcasting station name and network name.
And the frequency information code (AF) of the network stations that are broadcasting the same program.

[Problems to be Solved by the Invention]

By the way, in the case of an in-vehicle receiver, the broadcast wave reception state may deteriorate as the vehicle moves. Therefore, the broadcast wave may not be properly received at the preset frequency. Therefore, in the RDS receiver, it is conceivable to store the frequency data (AF data) of the group of network stations broadcasting the same program in advance in the memory for each preset channel.
A large memory area for storing AF data is required, and either a controller with a larger RAM capacity than that used for conventional radio receivers must be used, or a separate storage element must be provided, which reduces cost. However, there was a problem that it was disadvantageous in terms of space.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to secure the minimum memory area and to use the same network even if the channel frequency data at the time of preset operation becomes inappropriate due to the movement of the vehicle. Identification code (PI
RDS that can always perform a desirable preset tuning operation by searching and tuning a broadcast wave having a code)
Aim to get a receiver.

[Means for Solving the Problems]

The RDS receiver according to the present invention includes a preset memory for storing frequency data and a network identification code for each preset channel, and means for reading frequency data from the preset memory in response to a read command and receiving a frequency according to the frequency data. If the network identification code of the received frequency cannot be received or if it does not match the stored network identification code, means for sequentially changing the reception frequency within the FM frequency range, and network identification stored in the process of changing the reception frequency Means for rewriting the frequency in the corresponding preset memory to the frequency of the broadcasting station when the broadcasting station of the same broadcasting content of a predetermined level or higher is received based on the code, and the original broadcasting station when the broadcasting station cannot be received. Is provided.

[Work]

In the present invention, the network identification code is stored in the preset memory in addition to the frequency data, and when the network identification code received when selecting the preset channel is different from the stored one or when the network identification code cannot be received FM broadcast frequency When a seek operation is performed within the range and a broadcasting station with the same broadcast content of a predetermined level or higher is received based on the storage network recognition code, the frequency in the corresponding preset memory is rewritten to the frequency of the broadcasting station, and the broadcasting station with this condition is selected. If not received, the original broadcasting station is received.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. First
The figure shows the configuration of the RDS receiver according to this embodiment. The FM multiplex broadcast wave received by the antenna 1 is selected by the front end 2 at the desired station, converted to the intermediate frequency IF, and then sent to the FM detector 3. Supplied. The front end 2 is controlled by a PLL circuit 6 including a programmable frequency divider, and a controller 10 sets a frequency division ratio to perform a tuning operation. The detection output of the FM detection unit 3 is supplied to a multiplex demodulation circuit (MPX) 5 via a noise canceller (NK) 4, and in the case of stereo broadcasting, it is separated into L (left) and R (right) audio signals. Further, the detection output of the FM detection unit 3 is input to the RDS decoder 9 via the 57KHz bandpass filter 8 and converted into data that can be discriminated by the controller 10. The controller 10 receives the information of the receiving station (the above-mentioned PI, AF, PS, T
(P, TA, etc.), and if the station currently receiving is the same as the frequency data in the preset channel memory 11, PI
Write the code in the corresponding PI code storage area (16 bits). Further, a level detection unit 7 for detecting a received signal level (electric field strength) based on the IF signal level, and an S level in the FM detection unit 3 when the IF signal level is equal to or higher than a predetermined level.
A station detection unit 12 that detects a receiving station and outputs a station detection signal when the detection output of the curve characteristic is within a predetermined level range is provided. The reception signal level and station detection detected by the level detection unit 7 are provided. The station detection signal output from the unit 12 is supplied to the controller 10. Further, the operation section 13 is provided with a preset channel button 14, and the user can select a desired station by pressing the preset channel button 14.

Next, the operation when the preset channel button 14 is pressed to perform the channel selection operation will be described with reference to the flowcharts of FIGS. 2 (A) to 2 (C). It is assumed that frequency data and PI code desired by the user have already been written in the frequency data storage area and the PI code storage area in the precent channel memory 11, as shown in Table 1.

When the preset channel button 14 is pressed, the frequency data is read from the corresponding preset channel memory 11 in step S1, the frequency corresponding to the read frequency data is received, and the PI code is detected for a predetermined time in step S2 and the received PI Determine if the code can be detected. If it cannot be detected, the process proceeds to step S4.If it can be detected, the PI code stored in advance in step S3 is compared with the received PI code.If they match, the process proceeds to step S14 to select a channel. To finish. If the stored PI code and the received PI code do not match, the process proceeds to step S4 and shifts to one round of PI search. In step S4, it is determined whether or not the currently received frequency is the upper limit of the FM frequency range, that is, 108 MHz. If it is the upper limit band edge, the lower limit band edge 8 is determined in step S6.
Receive 7.5MHz and step if not upper band edge
One step higher with S5 (25KHz or 50KHz or 100K
Hz) Receive frequency. Next, in step S7, it is determined whether or not the reception frequency matches the search start frequency, and if they do not match, it is determined in step S8 whether or not there is a station detection signal. In S9, it is determined whether the received signal level is equal to or higher than a predetermined level, and if it is equal to or higher than the predetermined level, it is determined in step S10 whether the received PI code and the stored PI code match. This is to repeat the above procedure until it is determined in step S7 that the broadcast station with the same broadcast content and good reception condition has returned to the original station, in other words, until it makes one round in the FM reception frequency range. Is to find out. If the PI codes match in step 10, that is, if the same broadcast content station is detected, the process proceeds to step S11, the received frequency is rewritten to the corresponding in-memory frequency storage area, and the preset channel selection operation ends.
In this case, the tuning frequency is automatically switched. On the other hand, if it returns to the original station in step S7, the process proceeds to step S12, and if the PI code is detected again for a predetermined time and it is possible to receive it, the stored PI code is received in step S13.
Rewrite to the code and memorize when the PI code cannot be received
The channel preset channel selection operation is terminated in step S14 without rewriting the contents of the PI code. If the stored PI code is not rewritten, it means that there is no good broadcasting station with the same broadcast content in this area.

〔The invention's effect〕

As described above, according to the present invention, simply adding a storage area for each PI code to each preset channel makes it easy to always select a desired preset even if the vehicle moves away from the service area of the frequency stored in the preset channel memory. Station operations can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an RDS receiver according to the present invention, and FIGS. 2A to 2C are flowcharts showing a preset channel selection operation of the RDS receiver according to the present invention. 2 ... Front-end, 3 ... FM detector, 5 ... Multiplexer demodulator, 6 ... PLL circuit, 7 ... Level detector, 9 ... RDS decoder, 10 ... Controller, 11 ...
Preset channel memory, 12 …… Station receiver, 13 ……
Operation part.

Claims (1)

[Claims] 1. An RDS receiver for receiving an RDS broadcast wave containing a network identification code, a preset memory for storing frequency data and a network identification code for each preset channel, and frequency data read from the preset memory in response to a read command. , A means for receiving a frequency corresponding to the frequency data, a means for sequentially changing the reception frequency within the FM frequency range when the network identification code of the received frequency cannot be received or does not match the stored network identification code, Means for rewriting the frequency in the corresponding preset memory to the frequency of the broadcast station when a broadcast station having the same broadcast content of a predetermined level or higher is received based on the network identification code stored in the process of changing the frequency, and the broadcast station. If the original broadcast station RDS receiver comprising the means for receiving.