JP2745825B2 - RDS receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a radio data system (hereinafter referred to as RDS) implemented in Europe.
The present invention relates to an RDS receiver capable of receiving a preset station even if the user is away from the service area of the preset station.

[0002]

2. Description of the Related Art When a broadcast station broadcasts, information relating to the program content is transmitted as data by multiplex modulation, and a desired program content can be selected on the receiving side based on the demodulated data. Thus, there is an RDS that can provide the service to a radio listener.

[0003] The RDS data includes a network identification code (PI), a traffic information station identification code (TP), a traffic announcement identification code (TA), and a program service name information code (PS) such as a broadcast station name or a network name. , A frequency information code (AF) of a network station group broadcasting the same program.

[0004]

By the way, in the case of an on-vehicle receiver, a broadcast wave receiving state may be deteriorated as the vehicle moves. Therefore, there is a possibility that the broadcast wave cannot be satisfactorily received at the preset frequency.

On the other hand, in the RDS receiver, a method is conceivable in which frequency data (AF data) of a network station group broadcasting the same program is previously stored in each memory of each preset channel. Requires a large memory area for storing AF data, and a controller having a larger RAM capacity than that used in a conventional radio receiver must be used, or a separate storage element must be provided. However, there is a problem that it is disadvantageous in terms of cost and space.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. By securing a minimum memory area, even if the channel frequency data at the time of the preset operation becomes inappropriate due to the movement of the vehicle, An object of the present invention is to obtain an RDS receiver capable of always performing a desired preset channel selection operation by searching and selecting a broadcast wave having the same network recognition code (P code).

[0007]

An RDS receiver according to the present invention comprises: a receiving unit capable of receiving an RDS broadcast wave including a network identification code;
A preset channel memory for storing data is provided,
Preset channel menu selected during preset tuning
Selects and receives broadcast stations with frequencies stored in memory
And the preset channel memory is
Stores network identification code for each channel,
Network identification code of the broadcast station received at the time of tuning
Correspond to the corresponding channel stored in the preset channel memory.
If it is different from the network recognition code,
Network identification code stored in the channel memory
Broadcasting stations with the same network recognition code as RDS broadcasting
Search and receive from within the transmission frequency range of the wave .

[0008]

According to the present invention, the preset channel menu is provided.
Mori uses a network recognition code for each preset channel.
And store the broadcast station's network
Network recognition code is stored in the preset channel memory.
If it is different from the corresponding network recognition code
The network stored in the preset channel memory.
Work recognition code and network recognition code match
Search for broadcasting stations within the transmission frequency range of RDS broadcast waves
Broadcast station that matches this network identification code.
I believe.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment.

In FIG. 1, an FM multiplex broadcast wave received by an antenna 1 is tuned to a desired station by a front end 2, converted into an intermediate frequency (IF), and then supplied to an FM detector 3. It has become.

The front end 2 is a PLL (phase locked loop) circuit 6 including a programmable frequency divider.
Is controlled by In the PLL circuit 6, the front end 2 performs a tuning operation by setting a frequency division ratio by a controller 10 described later.

The detection output of the FM detection unit 3 is supplied to a multiplex (hereinafter, referred to as MPX) demodulation circuit 5 via a noise canceller (hereinafter, referred to as NK) 4. In the case of stereo broadcasting, the MPX demodulation circuit 5 separates the audio signal into L (left) and R (right) channel audio signals.

Further, the detection output of the FM detector 3 is 57
The data is input to the RDS decoder unit 9 via the KHz bandpass filter 8 and is converted by the controller 10 into identifiable data.

In the controller 10, information on a receiving station, that is, a network identification code (hereinafter, referred to as a PI code), a frequency information code (hereinafter, referred to as a PI) of a group of network stations,
Called AF), program service name information code such as a broadcast station and a network name (hereinafter, referred PS), traffic information station identification area (hereinafter, referred to as TP), Traffic Announcement identification code (hereinafter, captures) of TA, If the currently receiving station is the same as the frequency data stored in the channel preset memory 11, the PI code is written in the corresponding PI code storage area (16 bits).

The level detector 7 detects the received signal level (electric field strength) based on the intermediate frequency signal level output from the FM detector 3, and the detected output is also input to the controller 10. It has become.

The intermediate frequency signal output from the FM detector 3 is also input to the station detector 12. The station detecting section 12 detects a receiving station when the intermediate frequency signal level is equal to or higher than a predetermined level and the detection output of the S curve characteristic in the FM detecting section 3 is within a predetermined level range, and sends a station detecting signal to the controller 10. Output.

On the other hand, reference numeral 13 denotes an operation unit.
3 is provided with a preset channel button 14. The preset channel buttons 14 are "1" to " 6 ".
There are six buttons marked with the numbers, and the user can select a desired station by pressing the preset channel button 14. The operation unit 13 is connected to the controller 10, and input data is input to the controller 10 by operating the preset channel button 14.

Next, the operation of the present invention will be described. The operation of the controller 10 of the RDS receiver of the present invention when the preset channel button 14 is pressed to perform a channel selection operation will be described with reference to FIGS. This will be described along the flowchart shown in FIG. In this case, the frequency data storage area and the PI code storage area in the preset channel memory 11 have already stored the frequency data and the P data desired by the user.
The I codes are stored as shown in Table 1 below. Table 1 f ₁ in ~f ₆ is frequency data, PI ₁ ~PI ₆ is a PI code.

[0019]

When the preset channel button 14 is pressed, first, in FIG. 2, the controller 10 reads out frequency data from the corresponding channel memory 11, and receives a frequency corresponding to the read out frequency data in step S1. Then, the signal is converted into an intermediate frequency signal, and this intermediate frequency signal is supplied to the FM detector 3.

The detection output output from the FM detection unit 3 is demodulated by an MPX demodulation circuit after canceling noise at NK4. In the case of a stereo broadcast, the detection output is separated into L and R channel audio signals and output. You.

The detection output is input to a 57 KHz band-pass filter 8 to extract a 57 KHz frequency component.
It is input to the controller 10 via the RDS decoder 9, and the controller 10 detects the PI code for a predetermined time in step S2, determines whether or not the received PI code can be detected. Step S2
The process proceeds from the YES side to step S3.

In step S3, the received PI
The received PI code is compared with a PI code stored in the preset channel memory 11 (hereinafter referred to as a stored PI code), and as a result of the comparison, the received PI code matches the stored PI code. If so, the process branches off from the YES side of step S3, the process proceeds to step S14 in FIG. 4, and the channel selection operation ends.

If the received PI code cannot be detected in step S2 and if the received PI code is not detected in step S3,
If the code does not match the stored PI code, the processing routine branches to the NO side, and the processing shifts to the one-round PI search in FIG.

Next, the processing routine of FIG. 3 will be described. In FIG. 3, it is determined in step S4 whether the frequency currently being received is the upper limit of the FM frequency range, that is, 108 MHz, and as a result of the determination, if the upper limit is a band edge, the process branches from the YES side in step S4. Then, the process shifts to step S6, where the lower limit band edge 87.5 MHz is received.

If it is determined in step S4 that the frequency is other than the upper limit, that is, if the frequency currently being received is other than the upper limit of the FM frequency range of 108 MHz, the process exits from the NO side in step S4 and proceeds to step S5. In this step S5, a frequency higher by one step (25 KHz or 50 KHz) is received, and in step S7, it is determined whether or not the reception frequency and the search frequency match.

If the result of this determination is that they do not match, the process proceeds from the NO side of step S7 to step S8, where the station detecting unit 12
It is determined whether or not the detection output of the curve characteristic is within a predetermined level range. If the detection output is within the predetermined level range, a station detection signal that has detected the receiving station is sent to the controller 10. It is determined that there is, and the process proceeds from the YES side of step S8 to step S9.

In step S9, the level detector 7 detects whether or not the received signal level is equal to or higher than a predetermined level based on the intermediate frequency signal output from the FM detector 3, and the level detector 7 detects If the received signal level is equal to or higher than the predetermined level, the process proceeds from the YES side of step S9 to step S10.

In step S10, the controller 1 determines whether the received PI code matches the stored PI code.
If the received PI code matches the stored PI code, it is determined that the broadcast station having the same broadcast content and a good reception state has returned to the original receiving station in step S7. In other words, the above procedure is repeated until one round of the FM broadcast reception frequency range is performed, thereby searching for a broadcast station.

If the received PI code and the stored PI code match in step S10 and the same broadcast content station is detected, the process proceeds from the YES side of step S10 to step S11 in FIG. In step S14, the reception frequency is rewritten in the corresponding preset channel memory 11, and the preset channel selection operation ends in step S14. In this case, the frequency has been automatically switched.

In step S7 of FIG. 3, if the received frequency matches the search start frequency, that is, if it returns to the original receiving station, the processing routine branches from the YES side of step S7. The process shifts to step S12 in FIG. 4, and detects the PI code again for a predetermined time,
If the detection is possible, the process moves from the YES side of step S12 to step S13.

In step S13, the received PI code is rewritten from the stored PI code stored in the preset channel memory 11 to the received PI code. Simultaneously with the end of the rewriting, the processing shifts from step S13 to step S14, and the preset channel selection operation ends.

If the PI code cannot be detected in step S12, the processing routine branches from NO in step S12 without rewriting the contents of the stored PI code stored in the preset channel memory 11. Then, in step S14, the preset channel selection operation ends. In this case, there is no good broadcast station of the same broadcast content in this area.

[0034]

As described above, according to the present invention, each program
Reset channel memory stores frequency data and
By storing the network recognition code and
Frequency data stored in set channel memory
Even if the desired broadcast cannot be received by
The same network as the network recognition code
By searching for a broadcast station with a network recognition code,
Preset tuning operation is performed properly even if
It is something that can be done .

[Brief description of the drawings]

FIG. 1 is a block diagram of an RDS receiver according to one embodiment of the present invention.

FIG. 2 is a flowchart showing an execution procedure of a controller in the RDS receiver of FIG.

FIG. 3 is a flowchart illustrating an execution procedure of a controller in the RDS receiver in FIG. 1;

FIG. 4 is a flowchart showing an execution procedure of a controller in the RDS receiver in FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 antenna 2 front end 3 FM detector 4 noise canceller 5 multiplex demodulator 6 PLL circuit 7 level detector 8 57 kHz bandpass filter 9 RDS decoder 10 controller 11 preset channel memory 12 station detector 13 operation unit 14 preset channel button

Claims (1)

(57) [Claims] 1. A receiving unit capable of receiving an RDS broadcast wave including a network recognition code ,
Preset channel memory for storing frequency data
The preset channel selected at the time of preset channel selection
Selects and receives a broadcast station of the frequency stored in the channel memory.
RDS receiver for receiving, wherein the preset channel is
Memory is network recognized for each preset channel
Stores the code and broadcasts received at the time of the above-mentioned preset channel selection
The station's network identification code matches the preset channel
Corresponding network identification code stored in the local memory
If it is different from the preset channel memory
Network recognition code and network recognition stored
Broadcasting stations with matching codes are transmitted in the transmission frequency range of RDS broadcast waves.
An RDS receiver for searching and receiving from within an enclosure .