JPH08162987A - Acoustic device for vehicle - Google Patents

Abstract

PURPOSE: To prevent interference under the condition of strong fields whose frequencies are the same as that of an FM modulator or its adjacent frequencies by making it possible to contract an antenna at the time of using the modulator. CONSTITUTION: The broadcasting radio wave received by an antenna 12 extending and contracting via a motor 11 is outputted as voice by an FM radio receiver 13. The antenna driving signal to be outputted from the FM receiver 13 to the motor 11 is selectively turned off in the on-state of the FM radio receiver 13 by a microcomputer 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle audio system equipped with an FM modulator capable of easily realizing a CD system.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 4A and 4B, an FM modulator 2 is connected to an FM radio receiver 1 and a CD player 3 as an acoustic unit other than the FM radio receiver 1 is used. Connect to modulator 2 and FM
When the radio receiver 1 is used, an antenna 5 for receiving radio waves from a radio station via a motor 4 as a driving means.
There is known a vehicle acoustic device 6 in which the vehicle is extended to maintain the extended state at a predetermined position (full extension or half extension).

The FM modulator 2 includes a main switch 7
A power source + B such as a battery via the main switch 7 and a modulator 8 for radio-modulating an audio signal output from the CD player 3, and a relay-type switching interlocked with the operation of the main switch 7. When the main switch 7 is turned on, the modulator 8 is driven by the power supply from the power source + B to drive the FM modulator 2
When the main switch 7 is turned off, the power supply from the power source + B is cut off, the driving of the modulator 8 is stopped, and the FM radio is used.

That is, when the main switch 7 is turned on,
As shown in FIG. 4 (A), in the changeover switch 9, when the contact B and the common C are connected and the main switch 7 is turned off, as shown in FIG. 4 (B), the changeover switch 9 has the contact A. And the common C are connected.

When the contact A and the common C are in the connected state, since the FM radio broadcast is being received, the antenna feeders L1 and L2 are in the connected state via the changeover switch 9 and thus the antenna. An antenna extension signal (antenna on signal) is output from the on signal output line L3 to extend the antenna 5.

[0006]

By the way, in the vehicle audio system 6 configured as described above, when the FM modulator 2 is used, the contact B and the common C are connected to each other. However, since the antenna extension signal from the antenna-on signal output line L3 is still output, the antenna 5 is still extended when the CD player 3 is driven by stopping the reception of FM radio broadcast. There was a concern that interference might occur under a strong electric field strength of the same frequency as the modulator used frequency or an adjacent frequency.

[0007] That is, FM with the antenna 5 extended
In the state where the modulator 2 is used, the contact B and the common C are in the connected state, but since the isolation between the contact A and the common C is not ∞, the radio wave leaking from the contact A causes interference. This is a factor.

The present invention has been made in view of the above circumstances, and the antenna can be contracted when the FM modulator is used. Therefore, interference under strong electric field strength at the same frequency as the modulator use frequency or adjacent frequency is prevented. It is an object of the present invention to provide a vehicle acoustic device that can be used.

[0009]

In order to achieve the object, the invention described in claim 1 is an FM which receives broadcast radio waves and outputs as audio by an antenna which expands and contracts via a driving means.
It is provided with a radio receiver and a control means for selectively turning off an antenna drive signal output from the FM radio receiver to the drive means when the FM radio receiver is on. And

[0010]

In the structure described in claim 1, the broadcast radio wave received by the FM radio receiver via the driving means is expanded and output by the FM radio receiver, and the control means drives the FM radio receiver. The antenna drive signal output to the means is selectively turned off when the FM radio receiver is on.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a vehicle audio system of the present invention will be described with reference to the drawings.

1 and 2, the vehicle acoustic sound 10
Is an antenna 12 that expands and contracts via a motor 11 as a driving unit, an FM radio receiver 13 that outputs the broadcast radio wave received by the antenna 12, and an FM modulator 14 that is connected to the FM radio receiver 13. , And a CD player 15. It should be noted that the vehicle audio system 10 shown in FIG. 1 shows only the main parts relating to the present invention, and may be equipped with, for example, a speaker, a display part, a main operation part, a magnetic tape reproducing device, or the like. There is.

The FM radio receiver 13 includes an execution switch 16 for turning on / off power supply from a power source + B such as a battery, a tuner 17, and a switch section 19 for turning on / off based on a control signal from a microcomputer 18. , And a modulator remote switch 20 for turning on / off the FM modulator 14.

The switch unit 19 includes an antenna remote switch 21 for turning on / off the output of the antenna remote signal from the microcomputer 18 to the motor 11, and a power source + B to F.
A supply switch 22 for controlling on / off of power supply to the M modulator 14 is provided.

The FM modulator 14 is a CD player 1
The modulator 23 includes a modulator 23 that modulates the audio signal output from the signal No. 5 into a frequency signal and outputs the frequency signal to the tuner 17, and a changeover switch 24 that is turned on / off by the microcomputer 18 or the supply switch 22.

The changeover switch 24 has a contact A connected to the motor 11, a contact B connected to the modulator 23,
And a contact point C connected to the tuner 17.

In the above configuration, the FM radio receiver 1
When using 3, the execution switch 16 is first turned on. In this case, as shown in FIG. 2, the modulator remote switch 20 is in the off state because the modulator 23 is not used.

When the execution switch 16 is turned on, a high level is output from the microcomputer 18 to the antenna remote switch 21, and the high output causes the antenna remote switch 21 to turn on and the microcomputer 18 sends an antenna remote signal to the motor 11. Is output, and this output causes the antenna 12 to expand and maintain the expanded state.

Further, the supply switch 22 from the microcomputer 18
Is output to the modulator 23, and the supply switch 22 is turned off by the output of this low, so that the modulator 23 is not supplied with power from the power source + B.

Further, the changeover switch 24 is in a state where the contact A and the contact C are connected, the reception frequency signal received by the antenna 12 is output to the tuner 17, and the tuner 17 outputs a sound to a speaker (not shown). The signal is output.

When using the CD player 15, as shown in FIG.
As shown in, the execution switch 16 is turned on as it is (or newly), and the modulator remote switch 20 is turned on from this state.

When the modulator remote switch 20 is turned on, a low is output from the microcomputer 18 to the antenna remote switch 21, and the antenna remote switch 21 is turned off by the output of this low to cause the antenna remote from the microcomputer 18 to the motor 11. The output of the signal is cut off, and the cutoff keeps the antenna 12 contracted and maintains the contracted state.

Further, the supply switch 22 is supplied from the microcomputer 18.
To the modulator 23, and the power supply + B supplies power to the modulator 23.

Further, the changeover switch 24 is in a state where the contact B and the contact C are connected, the audio signal output from the CD player is modulated into a frequency signal by the modulator 23, and then output to the tuner 17. The tuner 17 outputs an audio signal to a speaker (not shown).

As described above, the vehicle audio system 10 of the present invention.
In this case, since the antenna 12 is contracted when the FM modulator 14 is used, the antenna sensitivity can be extremely reduced, and the induced voltage is suppressed even under a strong electric field strength. Contact A of the selector switch 24
It is possible to eliminate the electroplating of radio waves between the contact point C and the contact point C, and consequently prevent interference.

By the way, the FM modulator 14 generally has an oscillation frequency of 88.3 MHz or 88.7 MHz.
Since it is fixed to, it is necessary to select the reception frequency when using the FM radio.

On the other hand, most of the current FM radios use the PLL synthesizer method, so if the microcomputer 18 receives 88.3 MHz or 88.7 MHz, it is determined that the CD player 15 is being used, and the microcomputer 1
By turning off the output of the antenna remote signal from 8 to the motor 11, the antenna remote switch 21 can be eliminated.

For example, assuming that the reference oscillation frequency of the microcomputer 18 is 50 KHz, when receiving 88.3 MHz, the local oscillation frequency is 77.6 MHz and the N value is 77.6 MHz ÷ 50 KHz = 1552. , 8
When receiving 8.7MHz, the local oscillation frequency is 78
MHz, and the N value is 78 MHz ÷ 50 KHz = 15
It becomes 60.

Then, as shown in FIG. 3, when the N value is recognized and the PLL circuit built in the tuner 17 is locked, the output of the antenna remote signal from the microcomputer 18 to the motor 11 is turned off.

Further, although the motor antenna (motor 11) vehicle has been described in the above embodiment, the same effect can be obtained with an antenna amplifier vehicle with a completely similar configuration.

At this time, the motor 11 is replaced with an antenna amplifier that uses the antenna ON signal as a power source, and when the FM modulator 14 is used, the antenna ON signal is not output to the antenna amplifier, so the antenna amplifier stops the amplification operation. Even under a strong electric field, radio waves are not output and no interference occurs.

As described above, the vehicle audio system 10 of the present invention.
In this case, since the antenna 12 can be contracted when the FM modulator 14 is used, the antenna sensitivity can be extremely reduced and the induced voltage can be suppressed even when the electric field strength is high, and switching can be performed. It is possible to eliminate the electroplating of radio waves between the contact A of the switch 24 and the common C, and consequently prevent interference.

[0033]

As described above, in the vehicle audio system of the present invention, the FM radio receiver for receiving the broadcast radio wave and outputting the sound by the antenna that expands and contracts through the driving means, and the FM radio. By providing a control means for selectively turning off the antenna drive signal output from the receiver to the drive means when the FM radio receiver is on, the antenna is contracted when the FM modulator is used. Therefore, it is possible to prevent interference under the strong electric field strength of the same frequency as the modulator use frequency or an adjacent frequency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part of a vehicle audio apparatus of the present invention, showing a state where an antenna is contracted and a CD player is used.

FIG. 2 is an explanatory diagram of a main part of the vehicle audio device of the present invention, in a state where an antenna is extended to listen to an FM radio broadcast.

FIG. 3 shows a second embodiment of the vehicle audio system of the invention,
It is a flowchart of the judgment system of the judgment means.

4A and 4B show a conventional vehicle audio system, in which FIG. 4A is an explanatory view of a main part when the main switch of the FM modulator is on, and FIG. 4B is a view of a main part when the main switch of the FM modulator is off. FIG.

[Explanation of symbols]

 10 ... Vehicle audio system 11 ... Motor 12 ... Antenna 13 ... FM radio receiver 18 ... Microcomputer

Claims (3)

[Claims] 1. An FM radio receiver for receiving broadcast radio waves and outputting audio by an antenna that expands and contracts via a driving means,
Vehicle sound, comprising: a control unit that selectively turns off an antenna drive signal output from the FM radio receiver to the drive unit when the FM radio receiver is on. apparatus. 2. The control means is a relay switch for selectively turning off an output of an antenna drive signal output to the drive means when the FM radio receiver is turned on. The vehicle audio device according to claim 1. 3. The control means selectively determines whether or not the tuning frequency when the FM radio receiver is on is a predetermined value and selectively outputs an antenna drive signal to be output to the drive means. The vehicle audio device according to claim 1, wherein the audio device is a determination unit that is turned off.