JP2556742Y2 - Radio receiver - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver using RDS (Radio Data System).
Using TP (Tourist Broadcast Display) code or TA (Traffic Information Broadcasting) code in DS, switch to traffic information broadcasting automatically even if you are currently listening to other stations or other sources. The present invention relates to an on-vehicle radio receiver that can be switched.

[0002]

2. Description of the Related Art There is known an RDS (radio data system) in which a receiver is provided with various functions by adding an inaudible signal to a VHF-FM transmission signal. Using TP code and TA code included in such RDS data,
Even if you are currently listening to other stations or other sources, you can automatically switch to traffic information broadcasting.

[0003] In a conventional RDS receiver, when using traffic information, when the electric field strength of the currently received broadcast radio wave becomes smaller than a predetermined value, a warning sound is issued to request the viewer to retune, or While automatically searching for another broadcasting station with a strong electric field strength and switching the receiving station, even when listening to a cassette or CD, when a TA code appears in the broadcast being received, the sound of the broadcasting station of that TA code is heard. Output.

[0004]

[Problems to be Solved by the Invention] In the above-mentioned conventional receiver, it is possible to switch to another broadcast station when the user leaves the broadcast service area being received by a long-distance drive or the like.
Each time the vehicle passes through the tunnel, a warning sound is issued to request the viewer to retune, and in the case of the automatic search, there is a problem that an unnecessary search operation is performed.

[0005] The present invention has been made in view of the above points, and its purpose is to automatically switch to a traffic information broadcast even when currently listening to another station or another source. An object of the present invention is to provide an in-vehicle radio receiver in which an alarm operation and an automatic search are prohibited for a temporary decrease in electric field strength such as when passing through a tunnel.

[0006]

The radio receiver according to the present invention is capable of receiving RDS data, receives TP and TA codes, and broadcasts the TA code when the TA code appears in the currently received broadcast. Radio reception that outputs the sound of the station and issues an alarm when the electric field strength of the currently received broadcast wave falls below a predetermined value, or automatically searches for another broadcasting station with a strong electric field and switches the receiving station. The apparatus is provided with a means for detecting a gradient of a decrease in electric field strength, and when the gradient of the decrease in electric field strength exceeds a predetermined value, the alarm and the search for a broadcast station are prohibited for a certain period.

[0007]

According to the radio receiver of the present invention, the search operation is performed due to a decrease in the electric field strength when leaving the service area of the traffic information broadcasting station currently being received. When the electric field strength temporarily decreases, it is detected that the slope of the decrease in the electric field strength exceeds a predetermined value, and the search is stopped for a certain period.

[0008] If the electric field strength recovers through a tunnel or the like during the certain period, unnecessary search operations can be avoided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A radio receiver according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a radio receiver according to an embodiment of the present invention. In the figure, reference numeral 1 denotes an antenna which absorbs a broadcast wave and sends an electric signal to a frequency converter 2. The frequency converter 2 outputs an intermediate frequency output signal of the difference between the frequency of the signal input from the antenna 1 and the frequency of the signal input from the PLL 3 to the intermediate frequency amplification detector 4. The intermediate frequency amplification detector 4 amplifies the FM-modulated intermediate frequency signal, which is an input signal, and then demodulates the signal.
Output to

The mute circuit 6 is a microcomputer 1
The input signal is output to the power amplifier 7 according to the output signal of No. 1 or the output is prohibited. The power amplifier 7 amplifies the input signal and drives the speaker 8.

The reception sensitivity detector 9 is an intermediate frequency amplification detector 4
And outputs the magnitude of the intermediate frequency signal to the microcomputer 11 as a digital value. RDS data demodulator 10
Outputs a digital signal obtained by decoding the inaudible signal demodulated by the intermediate frequency amplification detector 4 to the microcomputer 11. Reference numeral 13 denotes a reception sensitivity decrease detector which compares the output of the reception sensitivity detector 9 at predetermined intervals, and when the inclination of the decrease in the reception sensitivity exceeds a predetermined value, sends a reception sensitivity decrease signal to the microcomputer 11. Output for a predetermined period.

The microcomputer 11 receives signals from the RDS data demodulator 10 and the reception sensitivity detector 9 in accordance with a program written in a ROM contained therein, and outputs a signal for determining an output frequency to the PLL 3, Further, it outputs a control signal to the mute circuit 6. At that time RA
The receiving station to be searched and various codes thereof are stored in M12.

In the above configuration, when receiving traffic information, the microcomputer 11 instructs the output frequency to the PLL 3 so as to receive the traffic information, and outputs the output of the mute circuit 6 when listening to another source. Is banned. During this time, the RDS data of the traffic information
When the A code appears, the microcomputer sets R
It is determined from the output of the DS data demodulator 10 and its TA
The data is output to the PLL 3 so as to receive the frequency of the broadcasting station of the code, and the mute circuit 6 outputs the audio signal.

Further, the microcomputer 11 constantly monitors the reception sensitivity detector 9 to determine whether the reception sensitivity has dropped below a predetermined value. If the reception sensitivity has dropped below the predetermined value, the microcomputer 11 stores the reception sensitivity in the RAM 12 in advance. A station having a strong electric field strength is searched from the traffic information broadcasting stations to be switched, and the receiving station is switched to that station. However, the above search is not performed while the reception sensitivity reduction signal is being output from the reception sensitivity reduction detector 13. If the reception sensitivity is higher than the predetermined value when the reception sensitivity reduction signal stops, the current reception station is continuously received.

Although the embodiment is configured as described above, the invention is not limited to this. For example, instead of a search performed when the reception sensitivity is lowered, an alarm sound is emitted to allow a listener to perform a search operation. Alternatively, the warning may be prohibited for a certain period when the gradient of the decrease in the electric field strength exceeds a predetermined value.

[0016]

According to the radio receiver of the present invention, when the mobile terminal deviates from the service area of the receiving traffic information station, it has a function of selecting another traffic information station, and furthermore, it passes through a tunnel. With respect to the temporary decrease in the electric field strength, the search operation and the output of the alarm sound are avoided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a radio receiver according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Frequency converter 3 PLL 4 Intermediate frequency amplification detector 5 Amplifier 6 Mute circuit 7 Power amplifier 8 Speaker 9 Reception sensitivity detector 10 RDS data demodulator 11 Microcomputer 12 RAM 13 Reception sensitivity reduction detector

Claims (1)

(57) [Scope of request for utility model registration] The present invention is capable of receiving RDS data, inputting a TP and a TA code, outputting a sound of a broadcasting station of the TA code when the TA code appears in a currently received broadcast, and outputting the currently received broadcast. When the electric field strength of the radio wave becomes smaller than a predetermined value, an alarm sound is generated, or a gradient of the decrease of the electric field strength is detected in a radio receiver which switches a receiving station by automatically searching for another broadcasting station having a strong electric field strength. A radio receiver comprising means for prohibiting the alarm or the search for a broadcast station for a certain period when the gradient of the decrease in the electric field strength exceeds a predetermined value.