JPH07235887A - Radio receiver - Google Patents

Abstract

PURPOSE:To prevent a voice output at the time of the reception at a broadcasting station other than an RDS station and to obtain the valid AF service by deciding the consecutive RDS data obtained at a demodulation section for a prescribed time or longer at the time of AF search and stopping the voice output operating a mute circuit when the data are not consecutive. CONSTITUTION:A microcomputer 9 is used to implement processing such as decision of an RDS station or setting of a reception frequency or the like. That is, the microcomputer 9 decides whether or not a frequency from a broadcast station is in existence in a searched frequency and decides whether or not the presence of RDS data is consecutive for a prescribed time of over when the frequency from a broadcast station is in existence. The microcomputer 9 decides activates a mute circuit 6 when the data are not consecutive for a prescribed time or over and executes the AF searching when the data are consecutive for a prescribed time or over. Thus, after the broadcasting station of a search destination is decided to be a stable RDS station, the signal from the broadcasting station being a searching destination is received and a voice output is implemented and no voice is outputted through the operation of a mute circuit before the decision.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver, and more particularly to a radio receiver effective for use in RDS.

[0002]

2. Description of the Related Art In Europe, an RDS (Radio Data System) has been put into practical use, which provides various services to vehicle drivers by digitally multiplexing tuning data and program identification data into FM radio broadcast signals. Cage,
It is expected that it will spread worldwide. Typical RDS services include a PI (program identification) service that identifies the country, the receiving area, and the program name of the broadcasting station, and a PS (displaying the receiving station name) service that displays the receiving broadcasting station name on the tuner display. , An AF (similar program broadcast frequency list) service that displays frequencies of other broadcast stations broadcasting the same program, and a TP service that identifies a broadcast station of traffic information.

The AF service has a search function so that when the reception electric field strength of an RDS radio wave transmitted from a broadcasting station by an in-vehicle tuner drops below a certain level, the radio wave of another broadcasting station of the same program broadcast can be received. ing. This search is performed based on the AF list stored in advance by storing the AF list transmitted from the broadcasting station in the memory.

For example, when the electric field strength of a radio wave from a certain broadcasting station becomes weak while driving in a car, other stations automatically transmitting the same broadcasting contents are automatically generated based on the AF list received in the receiving area. To receive. At that time, the AF list stored in the vehicle-mounted memory is updated to the AF list received in the area.

By the way, in the AF search in the conventional RDS radio receiver, the PI code data included in the RDS data is input in order to determine whether the broadcast station of the search destination is the RDS station during the AF search. After waiting for a certain period of time (for example, 700 msec), as a result of the matching judgment of the input PI codes, if they match, the normal AF service operation is performed, and if they do not match, the original frequency before the AF search is restored. .

[0006]

As described above, the AF service processing of the conventional RDS radio receiver is executed.
However, in the conventional RDS radio receiver, during the AF search, it is determined whether or not the broadcast station of the search destination is the RDS station by waiting for the input of the PI code data.
If the search destination is not an RDS broadcasting station, for example, 700
For a time of msec, a broadcasting station that is not an RDS station is received and audio is output (for a moment, the state of another station), which causes a hearing problem such as sound interruption to the user.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a radio receiver which can prevent a voice output from being received by a broadcast station other than an RDS station and can obtain a more effective AF service.

[0008]

In order to solve the above-mentioned problems, the radio receiver according to the present invention receives RDS data and determines the reception status based on the AF list included in the RDS data obtained by the demodulation unit. In an RDS receiver that performs an AF search operation that automatically switches to a good station,
During the F search, it is determined whether or not the RDS data from the demodulation unit continues for a predetermined time or longer. If not, the mute circuit is operated and the reception frequency before the AF search is set, and the RDS data is set for the predetermined time. When the above continues, the operation of the mute circuit is stopped and the A
It is configured to continue the F search operation.

[0009]

According to the present invention, in the RDS receiver, during the AF search, it is determined whether or not the RDS data obtained by the demodulation unit continues for a predetermined time or longer. If not, the mute circuit is operated to stop the audio output, Set the reception frequency before AF search. Further, when it continues for a predetermined time or longer, the operation of the mute circuit is stopped, the sound is output, and the AF search operation is continued.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a flowchart showing an operation processing procedure of an embodiment of a radio receiver according to the present invention.
Further, FIG. 2 is a block diagram showing the configuration of a radio receiver for realizing this embodiment.

First, the configuration of the radio receiver of this embodiment will be described with reference to FIG. 2. The reception signal received by the antenna 1 is converted into an IF signal by the front end 2. The front end 2 has a voltage controlled oscillator (VCO) and a mixer built therein, and cooperates with the PLL circuit 3 to set a reception frequency based on a control signal from the microcomputer 9. The converted IF signal is detected by the IF detection circuit (IF / DET) 4 and then the volume circuit 5
Adjust the volume with.

The output of the IF detection circuit 4 is detected by the reception sensitivity detection circuit 7 as the reception sensitivity, for example, as the electric field strength, and is sent to the microcomputer 9. The RDS data demodulation circuit 8 demodulates the detection signal from the IF detection circuit 4 and sends the obtained RDS data to the microcomputer 9.

The microcomputer 9 receives the sensitivity signal from the reception sensitivity detection circuit 7 and the RDS data from the RDS data demodulation circuit 8 to perform the RDS service.
The RAM 10 is a memory that stores the AF list included in the received RDS data.
Is read out and updated.

The mute circuit 6, under the control of the microcomputer 9, subjects the audio signal from the volume circuit 5 to mute processing. The audio signal passing through the mute circuit 6 is amplified by the output amplifier 11 and then output from the speaker 12.

In the present embodiment, the microcomputer 9 performs processing such as determination of the RDS station and setting of the reception frequency. The processing procedure will be described below with reference to FIG.

After the AF search is started, the frequency to be searched is first output (step S1), and it is determined whether or not there is a broadcasting station at that frequency, for example, by detecting the electric field strength (step S2). If there is no broadcasting station, the frequency is returned to the original frequency (step S6), the process is terminated, and if it is determined that there is a broadcasting station, the presence of RDS data output from the RDS data demodulation circuit 8 is determined in advance. It is determined whether or not it has continued for a certain time or more (step S3). This determination is usually about 70 msec to 80 msec. If it has not continued for a certain period of time, it is considered that the reception is unstable and the frequency returns to the original frequency (step S
6) If the processing is completed and continues for a certain time or longer, it is recognized as a stable RDS station, and the PI code is determined (step S4). Subsequently, it is determined whether the PI codes of the original broadcasting station and the current broadcasting station match (step S5). If they do not match, the process proceeds to step S6. If they match, the AF search process ends. And

In the present embodiment, after it is determined that the broadcast station of the search destination is a stable RDS station, the broadcast station of the search destination receives and outputs audio, and before that, the audio is output by the mute circuit operation. Is not output. If it is determined that the station is the RDS station, the voice is output and the PI of step S5 is output.
When the PI code does not match as a result of the code matching judgment, a broadcasting station other than the original broadcasting station is received and voice output as in the conventional case, but the reception and the voice output of the broadcasting station which is not the RDS station are lost. Significant improvement is achieved in comparison.

[0018]

As described above, according to the radio receiver of the present invention, the time during the so-called temporary other station state in which the broadcasting station other than the RDS station is received and the voice is output during the AF search is different from the conventional one. It can be greatly shortened in comparison.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation processing procedure of an embodiment of a radio receiver according to the present invention.

FIG. 2 is a configuration block diagram of a radio receiver for realizing the present embodiment.

[Explanation of symbols]

 1 Antenna 2 Front End 3 PLL Circuit 4 IF Detection Circuit 5 Volume Circuit 6 Mute Circuit 7 Reception Sensitivity Detection Circuit 8 RDS Data Demodulation Circuit 9 Microcomputer 10 RAM 11 Output Amplifier 12 Speaker

Claims (1)

[Claims] 1. An RDS receiver that receives an RDS data and performs an AF search operation of automatically switching to a station in a good reception state based on an AF list included in the RDS data obtained by a demodulation unit. At the time of search, it is determined whether or not the RDS data from the demodulation unit continues for a predetermined time or longer. If not, the mute circuit is operated and the AF
A radio receiver, characterized in that a reception frequency before a search is set, and when the predetermined time or more continues, the operation of the mute circuit is stopped and the AF search operation is continued.