JPS6228092Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an electronic volume control circuit for a car stereo.The purpose of this invention is to mount the main body of the car stereo in a comfortable place out of the driver's reach. The present invention aims to provide a car stereo in which an operating part such as a volume switch of the car stereo is incorporated in a place close to the driver's seat, for example, in the steering wheel of an automobile.

Currently, many devices such as automobile instruments, car coolers, and drive computers are installed near the front of the driver's seat of automobiles. As a result, it has become difficult to install a car stereo within the driver's reach. Therefore, there is a need for a device that allows a car stereo to be mounted outside the driver's reach and that can be operated automatically by instantaneous operation by the driver.

The present invention addresses this problem, and the configuration will be explained below using the drawings shown as one embodiment.

FIG. 1 is a block diagram of the circuit of the present invention. 1,
2 is a volume control circuit, and by changing the bias of this circuit by the DC control circuit 3, the gains of the left and right channel amplifiers are changed. CHL-I indicates left channel input, CHR-I indicates right channel input, and CHL-O and CHR-O indicate left channel output and right channel output, respectively. Note that 4 is the upper limit of the volume, 5
is the volume lower limit setting device. 6 is a volume control switch, and when the up side of this volume control 6 is activated momentarily, the counter ON/OFF circuit 7 is activated and continues to be in the ON state, and during that time T, the output of the up/down counter circuit 8 is output. The counter circuit output power V shown in FIG. 2 is obtained. D/A converters 9 and 10 are inserted between the up/down counter circuit 8 and the bias DC control circuit 3, and the digital counter output voltage is converted into an analog value as shown in FIG. The volume control voltage V on the horizontal axis is obtained. The vertical axis shows the volume attenuation amount dB. Therefore, the volume control circuit should be adjusted according to the appropriate volume control voltage.
The DC bias is determined and the gain of the amplifier at that time is determined. Counter ON/OFF circuit 7
When it is in the ON state, momentary operation of the hold switch 11 turns it into the OFF state, stopping the change in the counter output voltage and stopping the change in volume of the car stereo. The bias DC control circuit 3 is equipped with a volume upper limit 4 and a volume lower limit 5 setting device, and by changing these settings, the upper and lower limits of the volume control voltage can be freely set. To explain the upper limit setting of the volume control voltage in FIG. 3, the volume attenuation amount corresponding to the volume control voltage at point C is OdB, and the volume becomes maximum.
The volume attenuation amount corresponding to the volume control voltage at point d is DdB, which is the lower limit of the upper limit setting value. In other words, the upper limit setting range of the volume control voltage is d
~c. Similarly, the lower limit setting range is O to a. Now, if the lower limit setting value of the volume control voltage is b and the upper limit setting value is e, the volume attenuation amount will change within the range B to E. Therefore,
The car stereo volume changes within the above setting range. FIG. 4 shows a system in which a volume control switch 6 and a hold switch 11 are installed in a place close to the driver's seat of a car, for example, in a steering wheel part 12 of the car, and the main body 13 of the car stereo is installed in a place away from the driver's seat 14. ing. FIG. 5 is an enlarged front view of the main part.

Since the present invention has the above-mentioned configuration, when you want to change the volume of the car stereo while driving a car, the volume of the car stereo changes by momentarily operating the volume control switch 6. Alternatively, the volume is fixed because the bias changes up to the lower limit setting value and does not change further. Therefore, by setting the upper and lower limits in advance, when you want to change the volume of the car stereo while driving, you can achieve your goal by just momentarily operating the volume control switch. If you want to stop the volume halfway within the upper and lower limit setting ranges, just operate the hold switch. still,
The volume control switch 6 and the hold switch 11, which are remote switches, do not receive audio signals and are controlled by control voltages, so there is no need to worry about noise, which has great practical effects.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the circuit of the present invention, Figure 2 is a diagram of changes in counter output voltage, Figure 3 is a diagram of changes in volume attenuation due to volume control voltage, and Figure 4 is a front view when installed in a car. Figure 5 is a front view of the same main part. 1, 2... Volume control circuit, 3...
DC control circuit, 4, 5... Volume upper limit, lower limit control device, 6... Volume control switch, 7... Counter ON/OFF circuit, 8
... Counter circuit, 9, 10 ... D/A converter, 11 ... Hold switch.

Claims (1)

[Scope of utility model registration request] A car stereo is equipped with an electronic volume that controls the volume of an amplifier by changing the bias of the volume control circuit using a DC control circuit. A D/A converter is connected between a counter circuit and a DC control circuit to obtain changes in bias, a counter ON/OFF circuit having a volume control switch and a hold switch is connected to this counter circuit, and a volume control switch is connected to a counter ON/OFF circuit having a volume control switch and a hold switch. By momentarily operating the hold switch, the counter ON/OFF circuit is operated continuously to obtain the output of the counter circuit, and by momentarily operating the hold switch, the counter ON/OFF circuit is operated continuously and the output of the counter circuit is obtained.
The ON/OFF circuit is turned OFF and the counter circuit is held at the desired volume position, and a volume upper and lower limit setting device that can freely set the lower and upper limits of the voltage in the volume control circuit is connected to the DC control circuit. An electronic volume control circuit for a car stereo, characterized in that the volume control switch and the hold switch are installed as a remote control switch near the driver's seat of an automobile.