JPS5987599A - Receiver applied for road traffic information system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to road traffic information (ARI = Autofah information) implemented in countries such as West Germany, Switzerland, and Austria.
0 <Background technology> A RI system is a system whose purpose is to inform car drivers of minute-by-moment road traffic information in the countries mentioned above, and is based on specific broadcasts. The following three special identification signals are transmitted from the broadcasting station so that traffic information broadcast from the station at intervals during normal FM stereo broadcasting can be received.

(1) 57KHz ARI station identification signal...S
The K signal is a signal that is constantly oscillated only by the station that announces traffic information (ARI station) among a plurality of FM stations, and is sent after being modulated in frequency by 5% with respect to the main carrier wave.

(2) 125FIz traffic information identification signal...D
K Signal When listening to FM broadcasts while tuned to an ARI station, this signal is transmitted from just before the traffic information announcement to just after the announcement ends, and has an A of 30% of the SK signal.
Sent with M modulation.

(3) Area identification signal: BK signal The country is divided into a plurality of areas, and a signal of 23.75Hz to 53.98Hz is assigned to each area so that traffic information for each area can be selectively received. In short, it is a signal that recognizes a broadcasting station.

In conventional receivers used in W's ARI systems, the radio waves of the SK signal become weak, and when this continues for 10 to 30 seconds, the oscillation circuit built into the receiver automatically operates. However, it has the disadvantage that the cost of the oscillation circuit is high.

This was invented in view of the <objective of the present invention>, and when the SK signal cannot be received except for the oscillation circuit as described above, the noise component from the radio circuit is output from the speaker and replaced with the above-mentioned warning sound. This is what we do.

Fourteenth Arrangement of the Present Invention> Hereinafter, one embodiment of the present invention will be described in detail in accordance with the accompanying drawings.

The attached drawing is an electrical circuit diagram showing one embodiment of the receiver according to the present invention. In the figure, 1 is an FM radio section including an FM front end and an IF circuit section, and its output is SK multiplied signal processing and DK multiplied signal processing. It is supplied to ICI for detection.

This ICI outputs L (Low) depending on the presence or absence of SK multiplication signal input.
) or H (Hi'gb) level, and a terminal (2) that processes the DK double signal and supplies it to the next IC2.

This IC2 outputs L or H depending on the presence or absence of the DK double signal.
It has a so-called switch function.

It is a 2-piece FM stereo multiplex demodulation circuit, and its L and R outputs are passed through volumes V and +V to a power amplifier 3 and a speaker 4L.

It is configured to be supplied to 4R.

5 is a preamplifier in the tape recorder section, and a magnetic head 14. , H,... The resulting audio signal is passed through the above volumes VL and V1 to the power amplifier 3.
and the speaker 41. It is designed to drive +4R.

The preamplifier 5 operates by receiving power from the power input terminal 51 when the mode changeover switch SW is in the tape position T, but stops outputting when a muting signal is input to the terminal 52.

Ql is a PNP type transistor, and its base is connected to the resistor (1) and the above IC+ terminal (
The emitter is connected to the output terminal of IC2, and the collector is connected to the diode D3 + resistor R2.
is connected to the base of an NPN transistor Q2, which together constitute a switching circuit.

Further, a resistor R3 is inserted between the emitter and base of this transistor Q1.

The emitter of the transistor Q2 is grounded, and the collector is connected to the base of an NPN transistor Q3.

The midpoint e! between the collector of transistor Q2 and the base of transistor Q3! The muting terminal 52 of the preamplifier 5 is connected to.

The transistor Q3 has its collector connected to the 10B power supply, and its emitter connected to the radio position R of the mode changeover switch SW and the power supply input terminal 21 of the FM stereo multiplex demodulation circuit 2 via the diode DI.
It is connected to the midpoint e2 between.

6 is R of the above FM stereo multiplex demodulation circuit 2.
Make a branch line that takes out part of the output, and connect capacitor C.
1 to the above midpoint HIfC.

This branch line 6 is connected to both input terminals of the power amplifier 3 via resistors R< and Rs at a portion (3) in front of the capacitor C1.

C2 is a capacitor which together with the resistor R5 constitutes a 30 second timer.

<Operation of the present invention> The present invention is implemented as described above, and its operation will be explained next.

Now, if you set your receiver to receive traffic information, the 5K (No. (
The ICI enters the radio circuit section 1 together with (b)) and processes the SK multiplied signal and sets the terminal (2) to the L level.

Therefore, the transistor Q1 is always turned on while this SK signal is input at a predetermined radio wave intensity or higher.

In this state, when the specific broadcasting station is not yet broadcasting traffic information, that is, when the DK double signal is not being input, IC2 sets its output to H level. An H level signal is applied to the transistor Q2 via the diode IL+ and the m resistor R2, and the transistor Q2 is turned on.

Therefore, since the collector of this transistor Q2 becomes L level, the next stage transistor Q3 is turned off, and a muting signal is input to the muting terminal 52 of the preamplifier 5 of the tape recorder section, and is not output. , the partial C offshore potential in branch line 6 is capacitor C
+ becomes L level through FM stereo multiplayer.
The R output from the demodulator circuit 2 is not supplied to the power amplifier 3 via the branch line 6.

In this way, from specific broadcasting stations to general FM stereo broadcasting and S
Period during which only the K times signal is transmitted (TI in Figure 2)
), when the mode selector switch λ is set to Radio
In this case, the demodulation circuit 2 operates and the F during the period Ti is
Take out the L and R outputs of the M stereo broadcast and send them to the power amplifier 3 through the volume vL and vR to the crab speaker 4.
Drive L and 4R.

On the other hand, during this period, when the mode changeover switch SW is in the tape position T, the preamplifier 5 receives 10B through the mode changeover switch SW and the power input terminal 51.
When power is supplied, the collector of the transistor Q2 is at L level, no muting signal is input, and the preamplifier 5 is in operation, and the power input terminal 21 (C is Since the demodulation circuit 2 has stopped operating because the 10B power is not input, the audio signal on the magnetic tape that has been big-amplified by the magnetic head H14, ■4. is sent to the power amplifier 3 through the preamplifier 5 and the volume ■□, , VR. In this state where traffic information is not being transmitted,
After the Ju1 interval T1 has elapsed and the period T2 begins, traffic information is broadcast from the above-mentioned specific broadcasting station instead of the general FM stereo broadcast, and at the same time the DK signal (Fig. 2 (c)) is transmitted.
) enters the radio circuit section 1, is detected by the ICI, and is input to the IC2.
The output, which was at the level, is changed to the L level, and as a result, the transistor Q2 is turned off.

When the transistor Q2 is turned off, its collector becomes H level, so the transistor Q3 is turned on and a muting signal is input to the preamplifier 5.
Become.

Therefore, when the DK double signal of is input, and the mode changeover switch SW is in the radio position R as described above, the 1B power is continuously supplied to the FM stereo multiplex demodulation circuit 2, so the demodulation circuit 2 demodulates the traffic information broadcast signal following the general FM stereo broadcast up to that point and sends it to the power amplifier 3 through the volumes VL and ■R to emit the traffic information from the speakers 4□ and 14R. As mentioned above, as the collector of the transistor Q2 becomes H level, the level of the branched In 6 section = Q becomes H level, so the R output of the FM stereo multiplex demodulation circuit 2 is transmitted through the branch line 6. The component is supplied to the inputs of 30 power amplifiers, and the volume of the traffic information of the above speakers 4L, 4R is set to the volume VL.
, increase it above the level set in vR.

Furthermore, when the DK double signal is input as described above, when the mode selector switch SW is in the tape position T and the tape recorder section is operating, the collector becomes H level when the transistor Q2 is turned off. Together, a muting signal is input to the muting terminal 52 of the preamplifier 5, and the transistor Q3 is turned on, so that the 1,000-B power supply is automatically applied to the FM stereo multiplex demodulation circuit 2 even though the mode selector switch SW is in the tape position T. Since the current is switched and the signal is no longer supplied to the preamplifier 5, the operation of the preamplifier 5 is interrupted.

That is, although the magnetic head H1+HR picks up the signal on the tape, since the preamplifier 5 is muted, the audio signal on the tape cannot be obtained by the speaker.

(-) On the other hand, in conjunction with the input of the 10B power supply to the FM stereo multiplex demodulation circuit 2, the demodulation circuit 2 operates to demodulate the traffic information broadcast and perform the same operation as in the case of the radio position described above. Traffic information is transmitted through speakers 4T, 4R
Make more noise.

Now, during the period T2 in which traffic information is transmitted and received in radio or tape recorder mode, for some reason, for example, because you are far away from a specific broadcasting station, the radio waves become weak and the above-mentioned SK When the double signal becomes weaker, the terminal (2) of CI becomes H level, the diode D2 becomes reverse biased, and as a result, the transistor Q1 turns on.

At this time, the base of the transistor Q2 rises to 10 potential through the resistor R3, but it takes about 30 seconds for the transistor Qt to turn off due to the time constant of the resistors R1, R3 and the capacitor C2. When the transistor Q2 is turned off, the transistor Q2 is also turned on, resulting in the same state as receiving the DK double signal, and the collector of the transistor Q2 becomes H level.

As a result, the level of part (2) of the branch line 6 also becomes H level, and the noise component of the radio circuit is supplied from the FM stereo multiplex demodulation circuit 2 to the power amplifier 3 including the branch line 6, driving the speakers 4 L+4R and causing traffic noise. It notifies you with a warning sound that information can no longer be received.

After this warning sound is emitted, the muting of the preamplifier 5 can be activated by operating the operation means shown in the figure to release the receiver from the state in which it can receive traffic information. If the signal strength of the SK signal returns to normal before the 30 seconds set by the time constant circuit consisting of the resistor R1 + R3 + capacitor C2 has elapsed, the original traffic information will be received. state.

<Effects of the present invention> As mentioned above, if the radio wave intensity becomes weak during the broadcast period of traffic information, especially if the radio wave of the SK signal becomes weak, the power of the FM stereo multiplex demodulation circuit will be lower than that of the FM stereo multiplex demodulation circuit. This is because the noise component in the radio circuit is supplied to the amplifier and the noise component is used to drive the speaker to notify that the traffic information broadcast radio waves have become weak.
This is an excellent invention that can be constructed at low cost since it does not require a special oscillation circuit as in the prior art.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of a receiver according to the present invention, and FIG. 2 is a signal waveform diagram provided for R) of the same receiver.

Claims (1)

[Claims] 1. Make only a specific broadcasting station that broadcasts traffic information during general broadcasting output an SK signal, and identify that this specific broadcasting station is broadcasting traffic information while broadcasting the above traffic information. This is applied to a road traffic information system that transmits the DK signal simultaneously from the broadcasting station of the above-mentioned ownership, and when the above-mentioned SK and DK double signals are being received at the same time and the above-mentioned traffic information is being received, the volume setting is In a device that emits sound at a volume higher than the level set by the volume through a speaker through a power amplifier, a circuit between the power amplifier and the demodulation circuit of the radio causes the power amplifier to output an output higher than the sound level set by the volume. provide means, and
A switching circuit is provided to operate the circuit means by operating only when receiving both the SI (signal and the DK double signal), and the switching circuit is configured to detect when the radio wave of the SK signal becomes weak. A receiver applied to a road traffic information system, comprising a timer circuit connected to the switching circuit to operate as if both the SK and DI (signals) had been received after a certain period of time.