JPH0523620U - Radio receiver - Google Patents

Abstract

(57) [Summary] [Purpose] In an on-vehicle radio receiver that automatically switches to traffic information broadcasting even when listening to other stations or other sources, such as when passing through a tunnel. The alarm operation and automatic search are prohibited when the electric field strength decreases. [Structure] A microcomputer 11 constantly monitors from the signal of the reception sensitivity detector 9 whether or not the reception sensitivity is lower than a predetermined value. When the reception sensitivity is lower than the predetermined value, a broadcasting station having a strong electric field strength Search for and switch the receiving station to that station. However, the above search is not performed during the output period of the reception sensitivity decrease signal output from the reception sensitivity decrease detector 13 when the inclination of the reception sensitivity decrease exceeds a predetermined value.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a radio receiver using an RDS (Radio Data System), and in particular, it is currently being used by using a TP (traveler broadcast display) code or TA (display during traffic information broadcast) code in the RDS. The present invention relates to an in-vehicle radio receiver that automatically switches to traffic information broadcasting even when listening to stations and other sources.

[0002]

[Prior Art]

 There is known an RDS (radio data system) in which a receiver has various functions by adding an inaudible signal to a VHF-FM transmission signal. By using the TP code or TA code included in such RDS data, the switch can be automatically switched to the traffic information broadcast even when listening to another station or another source at present.

In the conventional receiver using the RDS, when using the traffic information, when the electric field strength of the currently received broadcast radio wave becomes smaller than a predetermined value, an alarm sound is emitted and the viewer is requested to retune, or , If another TA station appears in the broadcast being received even while listening to a cassette or CD while automatically switching to the other station by automatically searching for another station with a high electric field strength, the audio of the station with that TA code Was being output.

[0004]

[Problems to be solved by the device]

 With the conventional receivers described above, it is possible to switch to another broadcasting station when it leaves the broadcasting service area currently being received by a long-distance drive, etc. Tuning is required, and in the case of automatic search, there is a problem that unnecessary search operation is performed.

The present invention has been made in view of the above points, and an object thereof is to automatically switch the switch to traffic information broadcasting even when currently listening to another station or another source. It is an object of the present invention to provide a receiver for an on-vehicle radio receiver in which alarm operation and automatic search are prohibited when the electric field strength temporarily decreases such as when passing through a tunnel.

[0006]

[Means for Solving the Problems]

 The radio receiver of the present invention is capable of receiving RDS data, inputs TP and TA codes, and when a TA code appears in the currently received broadcast, outputs the audio of the broadcasting station of the TA code, and receives the current reception. A warning sound is emitted when the electric field strength of the inside broadcasting radio wave becomes lower than a specified value, or the gradient of the decrease in the electric field strength is detected in a radio receiver that automatically searches for another strong broadcasting station and switches the receiving station. Is provided, and the alarm and the search of the broadcasting station are prohibited for a certain period when the gradient of the decrease in the electric field strength exceeds a predetermined value.

[0007]

[Action]

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

Unnecessary search operation can be avoided if the electric field strength is restored by passing through a tunnel or the like during the fixed period.

[0009]

【Example】

 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 which is an embodiment of the present invention. In the figure, 1 is an antenna that absorbs broadcast radio waves and sends an electric signal to a frequency converter 2. The frequency converter 2 outputs an output signal of an intermediate frequency, which is 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 as an input signal, demodulates it, and outputs it to the mute circuit 6.

The mute circuit 6 outputs an input signal to the power amplifier 7 according to the output signal of the microcomputer 11 or the output is prohibited. The power amplifier 7 amplifies the input signal and drives the speaker 8.

The reception sensitivity detector 9 outputs the magnitude of the intermediate frequency signal in the intermediate frequency amplification detector 4 to the microcomputer 11 as a digital value. The 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 is a reception sensitivity decrease detector, which compares the output of the reception sensitivity detector 9 every predetermined period, and when the slope of the decrease in the reception sensitivity exceeds a predetermined value, a reception sensitivity decrease signal is sent 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 according to a program written in a ROM incorporated therein, and outputs a signal for determining an output frequency to the PLL 3, It also outputs a control signal to the mute circuit 6. At that time, the receiving station to be searched and various codes thereof are stored in the RAM 12.

In the above configuration, when the traffic information is received, the microcomputer 11 commands the output frequency to the PLL 3 so as to receive the traffic information, and the output of the mute circuit 6 when listening to another source. Is prohibited. During this period, when the TA code appears in the RDS data of the communication information being received, the microcomputer judges it from the output of the RDS data demodulator 10 and causes the PLL 3 to receive the frequency of the broadcasting station of the TA code. The data is output and the mute circuit 6 is caused to output an audio signal.

Further, the microcomputer 11 constantly monitors whether or not the reception sensitivity is lower than a predetermined value from the signal of the reception sensitivity detector 9, and when the reception sensitivity is lower than the predetermined value, it is stored in the RAM 12 in advance. Search the stored traffic information broadcasting station for one with a strong electric field strength and switch the receiving station to that station. However, the above search is not performed while the reception sensitivity decrease signal is being output from the reception sensitivity decrease detector 13. Then, if the reception sensitivity is higher than the predetermined value when the reception sensitivity lowering signal is stopped, 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 the search performed when the reception sensitivity is lowered, an alarm sound is emitted to allow a listener to perform a search operation. The alarm may be prohibited for a certain period when the gradient of the decrease in the electric field strength exceeds a predetermined value.

[0016]

[Effect of the device]

 According to the radio receiver of the present invention, it has a function of selecting another traffic information station when it goes out of the service area of the traffic information station being received, and the electric field strength such as passing through a tunnel is temporary. The search operation and the output of the alarm sound are avoided for the decrease of.

[Brief description of drawings]

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

[Explanation 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 decrease detector

Claims (1)

[Scope of utility model registration request] 1. When receiving RDS data, inputting a TP and TA code, and when a TA code appears in a broadcast currently being received, the sound of a broadcasting station having the TA code is output, and the broadcast currently being received. When the electric field strength of the radio wave becomes smaller than a predetermined value, an alarm sounds or a radio receiver that automatically searches other broadcasting stations with strong electric field strength to switch the receiving station detects the slope of the decrease in the electric field strength. A radio receiver provided with means for prohibiting the alarm or the search of the broadcasting station for a certain period when the gradient of the decrease of the electric field intensity exceeds a predetermined value.