JPS5953629B2 - audio equipment - Google Patents

Description

[Detailed description of the invention] This invention relates to an audio device.

In West Germany, a traffic information system called AR technology is currently being put into practical use. The outline of this traffic information system will be briefly explained below. This traffic information system is based on a traffic information system in which certain FM broadcast stations occasionally broadcast traffic information, such as information such as where an accident occurred on a motorway in West Germany, or where there is a stoppage. The aim is to provide convenience for The frequency spectrum of this traffic information system is shown in FIG. 1, and will be explained in detail. A, B and C are normal stereo signals, the main channel signal,
These are a pilot signal and a subchannel signal. D is a traffic signal related to the traffic information system, and the center line is 57K.
H2 spectrum, lines on both sides are 57KH2±125H
2 spectrum is shown. The signal of 57KH2 is
This is a sign that even if the broadcasting station that broadcasts traffic information is not currently broadcasting it, it will one day be broadcasting it.

Therefore, if you listen to the FM broadcasting station that broadcasts the signal 57KH2, you will eventually be able to hear traffic information. Note that the traffic information is sent on the main channel signal A (SK system). And 57KH2
If the signal is further AM-modulated with a 125H2 signal, it is a sign that general broadcasting is currently being interrupted and traffic information is being broadcast (DK system). The above is a system called SDK among commonly used traffic information systems. In addition, West Germany is divided into six regions, and an independent identification signal is set up between 28Hz and 56Hz for each region, and the 57KH2 signal is converted to AM using this identification signal.
There is a BK system that modulates and transmits information, and together with the SDK system, a traffic information system is configured as an SDBK system. Conventional audio equipment equipped with this traffic information system has a radio receiver tuned in advance to an FM broadcast station that broadcasts traffic information using SK signals, and when listening to a cassette tape by operating a cassette tape player, When information broadcasting starts, the music reproduction signal from the cassette tape player is interrupted by the DK signal, and the traffic information broadcasting signal from the radio receiver is transmitted from the speaker. However, such conventional audio devices have the problem that no matter how much the listener wants to hear traffic information, the music playback signal suddenly stops and switches to the traffic information broadcast signal, giving the listener a momentary discomfort. Ta.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an audio device that can alleviate the discomfort experienced by listeners when switching from a music reproduction signal to an information broadcasting signal.

An embodiment of the invention is shown in FIGS. 2 and 3.

In FIG. 2, an FM radio wave input to an antenna ANT is amplified by a high frequency amplification circuit 1 and converted to an intermediate frequency by a frequency conversion circuit 2. 3 is a local oscillation circuit.

4 is an intermediate frequency amplification circuit, 5 is an FM detection circuit, and the first
Outputs the spectrum signal shown in the figure.

6 is a stereo demodulation circuit.

7 is an SDK signal detection circuit, 8 is a switching circuit, 9 is an equalizer amplifier circuit for a power set tape player which is a recording/reproducing device, 10 is a low frequency amplifier circuit, 11 and 12 are speakers, and 13 and 14 are magnetic heads.

Now, the reception frequency of the radio receiver is 57KHz0)SK
Set it to an FM broadcast station that has a signal, that is, an FM broadcast station that will broadcast traffic information at some point. Then, the SDK signal detection circuit 7 detects the 57KHz0)SK signal and lights up the light emitting diode D, which is an indicator. When the power set tape player is operated in this state, the switch SW is turned on and the switching circuit 8 is switched to output only the music reproduction signal of the power set tape player. Therefore,
The sound of the power set tape can be enjoyed from the speakers 11 and 12. And 57KHz is 125Hz7! A
When the M-modulated DK signal is input, a signal is sent from the SDK detection circuit 7 to the switching circuit 8, and the switching circuit 8 is switched to output the traffic information broadcast signal from the radio receiver. At this time, a crosstalk circuit from the power set tape player to the output is provided inside the switching circuit 8 so that the music playback signal from the power set tape player is also output at a low level. In this way, the music from the power set tape can be heard in the background along with traffic information announcements, and when the traffic information announcement changes, the unpleasant feeling of the music from the power set tape suddenly stopping can be alleviated, and the music from the power set tape can be heard in the background. It can make the atmosphere softer and darker. FIG. 3 shows a specific circuit of the switching circuit 8. This switching circuit 8 outputs the music playback signal of the left channel and right channel power set tape player and the traffic information broadcast signal intermittently broadcast from the radio receiver. Input end S, a, Slb: S2a
, S2b, which normally output a music playback signal as an input signal, and switch the output signal from the music playback signal to the traffic information broadcast signal in response to the detection signal of the SDK detection circuit 7, and these changeover switches. S,,
S2's input end Sla, S2a output end S,.

, S2. Crosstalk resistors Rl and R2 are inserted and connected between the two. To explain the operation of the switching circuit 8 in detail, the switching switches S, , S2 use the signals from the switch SW and the SDK detection circuit 7 to switch between the power set tape player side (input ends Sla, s2a) ρ) and the radio receiver side (
input terminal Slb, S2b).

When the force set tape is pushed in and the force set tape player is operated, the switch SW is turned on, and at this time,
If there is no DK signal, the signal from the SDK signal detection circuit 7 is at a low level, and the low frequency amplification circuit 10 is connected to the equalizer amplification circuit 9 of the power set tape player. Output. Then, when the DK signal is input to the SDK signal detection circuit 7, the output of the SDK detection circuit 7 becomes high level, the changeover switches Sl and S2 are switched to the radio receiver side, and the traffic information broadcast signal of the radio receiver is switched to the radio receiver side. is output from the speakers 11 and 12. In this case, even if the switches S1 and S2 are switched to the radio receiver side, the signal from the power set tape player crosstalks to the output at a small level determined by the resistance values of the crosstalk resistors R1 and R2. Therefore, if the power set tape player is operating, the sound of the cassette tape player will be heard in the background of the sound from the radio receiver, ie, traffic announcements. As a result of this configuration, the music playback signal can be heard in the background while listening to the traffic information broadcast signal, so that discomfort when switching from the music playback signal to the traffic information broadcast signal can be alleviated. Note that an SDBK signal detection circuit may be used instead of the SDK signal detection circuit 7, and the switching circuit 8 may be built into a radio receiver with a power set tape player, or may be of an adapter type. .
As described above, the audio device of the present invention has the effect of alleviating the listener's discomfort when switching from a music reproduction signal to an information broadcasting signal.

[Brief explanation of the drawing]

FIG. 1 is a spectrum diagram of FM radio waves in a traffic information system, and FIGS. 2 and 3 are a block diagram and a main circuit diagram of an embodiment of the present invention, respectively. 1...High frequency amplifier circuit, 2...Frequency conversion circuit, 3...Local oscillation circuit, 4...
・Intermediate frequency amplification circuit, 5...FM detection circuit, 6
...Stereo demodulation circuit, 7...SDK
Signal detection circuit, 8...Switching circuit, 9...
・Equalizer amplifier circuit, 10...Low frequency amplifier circuit, 11, 12...Speaker, 13, 14...
...Magnetic head, ANT...Antenna, D
...Light emitting diode, SW ... switch, Sl, S2 ... changeover switch, Rl, R2
・・・・・・Resistance for crosstalk.

Claims (1)

[Scope of Claims] 1. An audio device that switches and listens to a music playback signal of a recording and playback device and an information broadcast signal broadcast intermittently, comprising a detection circuit that detects the information broadcast signal, and a detection circuit that detects the information broadcast signal, and the music playback signal. signal and the information broadcasting signal as input signals to the first and second input terminals, respectively, and normally output the music reproduction signal, and in response to the detection signal of the detection circuit, convert the output signal from the music reproduction signal to the information. An audio device comprising a switching circuit for switching to a broadcast signal, and a crosstalk circuit inserted and connected between a first input terminal and an output terminal of the switching circuit. 2. The audio device according to claim 1, wherein the crosstalk circuit comprises a resistor.