JPH04235408A - Rds receiver - Google Patents

Abstract

PURPOSE:To always perform desirable preset station selection operation by ensuring minimum preset channel memory area even when the channel frequency data at the time of the operation of the preset is not proper by the moving of vehicles. CONSTITUTION:When the received network recognition code is different from the network recognition code stored in a pertinent preset channel memory 11 at the time of the preset channel station selection, the seek operation is performed by making a round within the frequency range for FM broadcasting. When the received network recognition code coincides with the stored network recognition code and coincides with it after making a round, it is rewritten in the preset channel memory 11. When the received network recognition code is not detected, it is not rewritten in the preset channel memory 11.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is applicable to the radio data system (hereinafter referred to as RDS) implemented in Europe.
The present invention relates to an RDS receiver that is capable of receiving a preset station even if the receiver moves away from the service area of the preset station.

0002

[Background Art] When a broadcast station broadcasts, information related to the program content is transmitted as data through multiplex modulation, and the desired program content can be selected on the receiving side based on the demodulated data. There is an RDS that can provide this service to radio listeners in this way.

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

0004

[Problems to be Solved by the Invention] In the case of a vehicle-mounted receiver, the broadcast wave reception condition may deteriorate as the vehicle moves. Therefore, there is a possibility that broadcast waves cannot be received well at the preset frequency.

On the other hand, in an RDS receiver, a method may be considered in which frequency data (AF data) of a group of network stations broadcasting the same program is stored in advance in a memory for each preset channel. In this case, a large memory area is required to store the AF data, and it is necessary to use a controller with a larger RAM capacity than that used in conventional radio receivers, or to provide a separate storage element. First, there was a problem that it was disadvantageous in terms of cost and space.

The present invention has been made to solve the above-mentioned problems, and by ensuring a minimum memory area, even if the channel frequency data at the time of preset operation becomes inappropriate due to movement of the vehicle, An object of the present invention is to obtain an RDS receiver that can always perform a desired preset tuning operation by searching and selecting broadcast waves having the same network recognition code (P code).

[0007]

[Means for Solving the Problems] An RDS receiver according to the present invention is capable of receiving RDS broadcast waves including a network recognition code, and has a preset channel in which frequency data and a network recognition code are stored for each preset channel. It has a memory and a preset reception function that reads frequency data according to a read command from the preset channel memory and receives a frequency corresponding to the read frequency data, and also changes the reception frequency sequentially within the FM frequency range, A receiver having a seek function for receiving stations having a predetermined electric field strength or higher based on a detection signal and a received signal level detection signal, and a receiver that always performs a preferable preset tuning operation based on the reception status of the receiver. A controller is provided.

[0008]

[Operation] In this invention, a network recognition code is stored in addition to frequency data in each preset channel memory, and the network recognition code received when selecting a preset channel corresponds to the network recognition code stored in the corresponding channel memory. When different from
Or, when the network recognition code of the receiving station cannot be received, the controller causes the receiver to seek within the FM broadcast frequency range, and based on the network recognition code stored in the preset channel memory, the same broadcast content is broadcast at a predetermined level or higher. Make the receiver receive the station, rewrite the frequency number in the corresponding preset channel memory using the controller, and when there is no station that satisfies the above conditions in the seek operation, make the receiver receive the original station under the control of the controller, and the frequency number in the corresponding preset channel memory is rewritten. To prevent the contents of a network recognition code stored in a preset channel memory from being rewritten when the network recognition code cannot be received.

[0009]

Embodiments Hereinafter, embodiments of the RDS receiver of the present invention will be explained based on the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment.

In FIG. 1, FM multiplex broadcast waves received by an antenna 1 are tuned to a desired station by a front end 2, converted to an intermediate frequency (IF), and then supplied to an FM detection section 3. It looks like this.

This front end 2 includes a PLL (phase locked loop) circuit 6 including a programmable frequency divider.
controlled by. In this PLL circuit 6, a frequency division ratio is set by a controller 10, which will be described later, so that the front end 2 performs a channel selection operation.

The detected output of the FM detection section 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, this MPX demodulation circuit 5 separates the audio signals into L (left) and R (right) channel audio signals.

Furthermore, the detection output of the FM detection section 3 is 57
The signal is input to the RDS decoder section 9 via the KHz bandpass filter 8, and is converted into distinguishable data by the controller 10.

[0014] The controller 10 receives information about receiving stations, that is, network recognition codes (hereinafter referred to as PI codes), frequency information codes of network station groups (hereinafter referred to as PI codes),
(hereinafter referred to as AF), program service name information code (hereinafter referred to as PS) such as broadcasting station or network name, and traffic information station identification area (hereinafter referred to as TP). When the traffic announcement recognition code (hereinafter referred to as TA) is imported and the station currently being received is the same as the frequency data stored in the channel preset memory 11, the PI code is stored in the corresponding PI code storage area (16 bits). It is designed to be written inside.

Based on the intermediate frequency signal level output from the FM detection section 3, a level detection section 7 detects the received signal level (electric field strength), and its detection output is also input to the controller 10. It looks like this.

The intermediate frequency signal output from the FM detection section 3 is also input to the station detection section 12. This station detection section 12 detects a receiving station and sends a station detection signal to the controller 10 when the intermediate frequency signal level is above a predetermined level and the detection output of the S curve characteristic in the FM detection section 3 is within a predetermined level range. It is designed to be output.

On the other hand, 13 is an operation section, and this operation section 1
3, a preset channel button 14 is provided. This preset channel button 14 is "1" to "16"
There are 16 buttons marked with numbers, and the user can select a desired station by pressing the preset channel button 14. This operation section 13 is connected to the controller 10, and input data is input to the controller 10 by operating a preset channel button 14.

Next, the operation of the present invention will be explained. The controller 1 of the RDS receiver of the present invention when the preset channel button 14 is pressed to perform a channel selection operation.
The operation of 0 will be explained along the flowcharts shown in FIGS. 2 to 4. In this case, the frequency data storage area and PI code storage area in the preset channel memory 11 already contain the frequency data and PI code desired by the user.
The codes are stored as shown in Table 1 below. f1 to f6 in Table 1 are frequency data, PI1 to
PI6 is the PI code.

[0019]

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

[0021] The detection output output from the FM detection section 3 has noise canceled by the NK4 and demodulated by the MPX demodulation circuit, and in the case of stereo broadcasting, it is separated into L and R channel audio signals and output. Ru.

The detection output is also input to a 57 KHz band pass filter 8, where a 57 KHz frequency component is extracted, and sent via an RDS decoder 9 to a controller 10.
In this controller 10, the PI code is detected for a predetermined period of time in step S2, and it is determined whether or not the received PI code can be detected. If the received PI code is detectable, the process goes from the YES side of step S2 to step S3. Processing is transferred.

[0023] In this step S3, the received PI
The code (hereinafter referred to as the received PI code) is compared with the PI code stored in the preset channel memory 11 (hereinafter referred to as the stored PI code), and as a result of the comparison, the received PI code matches the stored PI code. If so, the process branches from the YES side of step S3 to step S14 in FIG. 4, and ends the channel selection operation.

[0024] Furthermore, if the received PI code is undetectable in step S2 and in step S3, the received PI code is
If the code does not match the stored PI code, the processing routine branches to the NO side and the processing moves to the PI search in FIG. 3.

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

Further, in step S4, if the frequency is not the upper limit, that is, if the currently received frequency is other than 108 MHz, which is the upper limit of the FM frequency range, step S4 is performed.
4, the process moves to step S5, and in this step S5, the frequency is one step higher (25KHz).
, or 50 KHz), and in step S7 it is determined whether the received frequency and the search frequency match.

As a result of this determination, if they do not match, the process proceeds from the NO side of step S7 to step S8, and in step S8, the station detection section 12 detects the S of the FM detection section 3.
It is determined whether or not the detection output of the curve characteristic is within a predetermined level range. If it is within the predetermined level range, a station detection signal that detects the receiving station is sent to the controller 10, and in this controller 10, the station detection signal It is determined that there is, and the process moves from the YES side of step S8 to step S9.

In this step S9, the level detecting section 7 detects whether the received signal level is a predetermined level or higher based on the intermediate frequency signal output from the FM detecting section 3. If the received signal level is equal to or higher than the predetermined level, the process moves to step S10 from the YES side of step S9.

In step S10, the controller 1 checks whether or not the received PI code matches the stored PI code.
0, and if the received PI code matches the stored PI code, the broadcasting content is the same and the broadcasting station with good reception status is selected until it is determined that it has returned to the original receiving station in step S7. In other words, the above procedure is repeated until one round within the FM broadcast reception frequency range to search for a broadcast station.

In this step S10, if the received PI code and the stored PI code match and the same broadcast content station is detected, the process moves from the YES side of step S10 to step S11 in FIG. Then, this received frequency is rewritten into the corresponding preset channel memory 11, and the preset channel selection operation is ended in step S14. In this case, the frequency is automatically switched.

Further, in step S7 of FIG. 3, if the receiving frequency matches the search start frequency, that is, if the receiving station returns to the original receiving station, the processing routine branches from the YES side of step S7, The process moves to step S12 in FIG. 4, and the PI code is detected again for a certain 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 used to replace the stored PI code stored in the preset channel memory 11 with the received PI code. At the same time as this rewriting ends, the process moves from step S13 to step S14, and the preset channel selection operation ends.

Further, in step S12, if the PI code cannot be detected, the processing routine branches from the NO side of 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 is ended. In this case, there is no broadcasting station with good reception of the same broadcast content in this area.

[0034]

[Effects of the Invention] As described above, according to the present invention, the PI code is stored in the preset channel memory,
When selecting a preset channel, if the received PI code is different from the stored PI code in the corresponding preset channel memory, or if the PI code of the receiving station cannot be received, seek within the FM broadcast frequency range and select a predetermined PI code based on the stored PI code. If the above conditions are not met even after receiving a broadcast station with the same broadcast content as above level and rewriting the contents of the corresponding preset channel memory to the frequency of this broadcast station, and performing a seek operation, the original broadcast When a station is received, or when the PI code and the stored PI code are different, the stored PI code is rewritten, and when the PI code cannot be received, the contents of the stored PI code are not rewritten, so each preset channel memory By simply adding a storage area for each PI code to the vehicle and moving the vehicle, a desired preset channel selection operation can be easily performed even if the vehicle leaves the service area of the frequency stored in the preset channel memory.

[Brief explanation of the drawing]

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

FIG. 2 is a flowchart showing an execution procedure of a controller in the RDS receiver of FIG. 1;

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

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

[Explanation of symbols]

1 Antenna 2 Front end 3 FM detection section 4 Noise canceller 5 Multiplex demodulation circuit 6 PLL circuit 7 Level detection section 8 57KHz bandpass filter 9 RDS decoder 10 Controller 11 Preset channel memory 12 Station detection section 13 Operation section 14 Preset channel button

Claims (1)

[Claims] [Claim 1] RDS including network recognition code
A front end that can receive broadcast waves, selects a desired station of FM multiplex broadcast waves, and outputs an intermediate frequency signal, an FM detection section that detects the intermediate frequency signal, and inputs the output of this FM detection section. a level detection section that detects a received signal level by detecting a receiving station and outputting a station detection signal by detecting a receiving station when the intermediate frequency signal level is above a predetermined level and the detection output of the FM detection section is within a predetermined level range. a station detection section;
Each preset channel has an operation section to be operated when selecting a preset channel, a phase-locked loop circuit that causes the front end to perform a channel selection operation according to a set frequency division ratio, and a storage location for a network recognition code, and for each preset channel. If the network recognition code received by the front end at the time of preset channel selection operation is different from the network recognition code stored in the corresponding preset channel memory, or if the received network recognition code is detected. If not, it performs a seek operation until it goes around the FM reception frequency once, and if it determines that the received network recognition code is the same as the stored network recognition code,
The frequency of the received network recognition code is rewritten to the corresponding preset channel memory, and if the received network recognition code can be detected after one round of the above seek operation, the frequency of the received network recognition code is rewritten to the corresponding preset channel memory. RDS comprising a controller that rewrites the contents and controls not to rewrite the contents of the preset channel memory if the received network recognition code cannot be detected.
Receiving machine.