JPH03176247A - Traffic information receiver - Google Patents

Abstract

PURPOSE:To reduce the generation of distortion even if suffering jamming such as multipass, etc. by forcibly conducting the output of a MPX (stereo multiplex) circuit in a monaural condition in the event of receiving data which indicates that traffic information is announced presently. CONSTITUTION:A MPX circuit 8 is constructed by a dividing circuit 81, a circuit 82 for conducting a sum signal component, a circuit for conducting a remainder signal components, and a matrix circuit 84 for separating left and right sound signals after receiving outputs from these two circuit 82, 83. The demodulation output from a receiver or a regenerative signal from a tapedeck 14 is alternatively output to output terminals Lout, Rout by the motion of a switching circuit 13. A signal which indicates that traffic information is announced presently is detected by a decoder 15. A switching control circuit 16 sends a control signal to a forced monaural control circuit 85 in the MPX circuit 8 to intercept output from the circuit 83 for conducting a remainder signal component. Consequently, the output from the MPX circuit 8 becomes monaural.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a traffic information receiver that receives a broadcast signal in which a data signal indicating that traffic information is being announced is multiplexed with a main signal and transmitted. It is something.

[Conventional technology and its problems]

Currently, in West Germany, the ARI system (Aut.

Fahrer Rundfnk Informat
A traffic information system for car radios called ion has already been put into practical use.

This ARI system uses the FM broadcast pilot tone (
A subcarrier is added to 57KHz, which is three times the frequency of 19Kflz), and this is used as a traffic information station identification signal (SK double signal) to indicate that the station broadcasts traffic information, and only when broadcasting traffic information. , this SK multiplied signal 12
It is modulated with a 5H2 frequency signal. This one
The 25 Hz signal is a message identification signal (commonly called a DK multiplied signal). Therefore, by demodulating and detecting this DK multiplied signal at the receiver, it can be identified that traffic information is being broadcast.

On the other hand, in Europe, bi-phase coded data signals are converted into FSK with a phase that is 90 degrees different from the 57 KHz subcarrier in the API system.
(Frequency 5hift Keyin
g) RDS (Radio Data
System) has been proposed and has entered the practical stage.

The data supplied in this RDS is formed into one group of four blocks each consisting of 26 bits, and a part of the second block contains a traffic information announcement identification code (Traffic Announcement Identification Code).
ent Identification (commonly known as TA code) is assigned one bit.

Therefore, in the RDS receiver, by demodulating and detecting this TA code, it is possible to identify that traffic information is being broadcast.

In a receiver capable of receiving ARI and RDS broadcasts as described above, by receiving and demodulating the DK double signal and TA code described above, it is possible to reproduce the broadcast signal only when traffic information is being broadcast, or For example, even when a tape deck is being played, it is possible to perform interrupt control such as preferentially switching to traffic information broadcasting.

However, in conventional traffic information broadcasting of this type, even when transmitting traffic information, it is sometimes broadcast in stereo mode, and therefore the receiver receives and reproduces the traffic information announcement in stereo reproduction mode.

At this time, especially in a vehicle-mounted receiver, distortion may occur due to the influence of multipath, etc., and a situation may occur in which information is difficult to hear.

Furthermore, with regard to traffic information, there is a desire to listen to information more accurately than in general music programs.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a traffic information receiver that automatically controls the broadcast content so that it is easier to hear the broadcast content when the traffic information is being received. That is.

[Summary of the invention]

In order to achieve the above object, the traffic information receiver according to the present invention forcibly sets the MPX circuit to a monaural operation mode when receiving a data signal indicating that traffic information is being announced. It is characterized by being able to avoid interference such as multipath.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The drawings show embodiments of the invention.

That is, 1 indicates a receiving antenna, and a radio frequency (RF) signal from this antenna 1 is amplified by an RF amplifier circuit 2 and then applied to a mixer 3.

A local signal from a local signal oscillator 4 is injected into the second mixer 3, and the input RF signal is converted into an intermediate frequency (IF) signal.

The intermediate frequency (IF) signal obtained by the mixer 3 is amplified by an IF amplifier circuit 6 and then subjected to FM detection by an FM demodulation circuit 7.

The demodulated output subjected to FM detection by the FM demodulation circuit 7 is applied to a stereo multiplex (MPX) circuit 8 and separated into left and right audio signals.

On the other hand, a station detection circuit 9 is connected to the IF amplifier circuit 6, which detects the IF level and generates an output when the IF level is higher than a predetermined level. '1■ Applied to the circuit 10.

A keyboard 11 and a display 12 that displays reception frequency, etc. are connected to the central control circuit 10. By operating the keyboard 11, the local signal oscillator 4
The system is configured to provide predetermined oscillation data to tune the broadcast frequency to a desired broadcast frequency.

As shown in the figure as an example, the MPX circuit 8 includes a dividing circuit 81 for dividing a human-powered composite signal, a circuit 82 for providing a sum signal (L+R) component obtained by this dividing circuit 81, and a difference signal (L+R) component. -R) circuit 8 providing the component
3, and a matrix circuit 84 that receives the outputs from these two circuits 82 and 83 and separates them into left and right audio signals, and a forced monaural control that cuts off the output of the circuit 83 that produces the difference signal (LR) component. A circuit 85 is added.

The left and right audio signals obtained by the MPX circuit 8 are applied to an output switching circuit 13.

This output switching circuit 13 includes, for example, a tape deck 14.
By the operation of the switching circuit 13, the demodulated output of the receiver or the reproduced signal from the tape deck 14 is applied to the output end Lout,
Output to Rout.

The demodulated output FM-detected by the FM demodulation circuit 7 is also applied to a decoder (data demodulation circuit) 15, and the decoder I5 generates a signal indicating that traffic information is being announced, that is, a DK multiplier in the API system. A TA code in the signal or RDS broadcast is detected.

When the decoder 15 detects the DK double signal or the TA code, the decoder 15 outputs an output to the switching control circuit 16, and the switching control circuit 16 sends an output to the MPX circuit 8.
Sending a control signal to the forced monaural control circuit 85 in
The output of the circuit 83 that provides the difference signal (LR) component is cut off (switch S is turned on).

Therefore, the output of the MPX circuit 8 is monaural, and the monaural signal is output to the switching circuit 13.

On the other hand, the output of the switching control circuit 16 is
It is configured so that it is also applied. In this selection control circuit 17, the output from the switching control circuit 16 is introduced into the switching circuit 13 in response to the output from the central control circuit 10 which receives a command from the keyboard 11. This results in
The playback state of the tape deck 14 is switched to the reception playback state of the receiver.

Therefore, the receiver is forced into a monaural state while receiving traffic information.

Note that the line from the central control circuit 10 to the selection control circuit 17 is, for example, a 3-state line, and as described above in the first state, when data indicating that traffic information is being announced is received, the tape deck 14 Interrupt control is performed from the playback state of the receiver to the reception playback state of the receiver, and in the second and third states, the tape deck 1
It is preferable to use the reproduction output from 4 and the reception demodulation output of the receiver for a function switching function to be provided to the output terminals Lout and Rout, respectively.

[Effect] As is clear from the above explanation, according to the present invention, when data indicating that traffic information is being announced is received, the output of the MPX circuit is forcibly made into a monaural state. Therefore, even if interference such as multipath occurs, the occurrence of distortion can be reduced.

Furthermore, monaural operation further improves the S/N ratio, making it possible to reliably listen to traffic information.

[Brief explanation of drawings]

The drawing is a block diagram showing an embodiment of the invention. l...Antenna, 2...RF amplifier circuit, 3...Mixer 4...Local signal oscillation circuit, 6...-IF
Amplifier circuit, 7... FM demodulation circuit, 8... MPX circuit, 9... Station detection circuit, 10... Central control circuit, 11
...Keyboard, 12...Display, 13...Switching circuit, 14...Tape deck, 15...Decoder (data demodulation circuit), 16...Switching control circuit, 17
...Selection control circuit.

Claims (1)

[Claims] A receiver that receives a broadcast signal that multiplexes a data signal indicating that traffic information is being announced on a main signal and sends it out, the receiver comprising a front end that receives the broadcast signal, and a broadcast that is tuned by the front end. A demodulation circuit that demodulates the main signal from the signal, and an MP that takes the signal obtained from this demodulation circuit as input and separates it into left and right audio signals.
an X circuit, a data demodulation circuit that demodulates the data signal from the broadcast signal tuned by the front end;
A traffic information receiver comprising: a switching control circuit that sends a control signal so that the output of the X circuit is in a monaural state.