JPH0246012A - Sound volume balance adjusting device - Google Patents

Abstract

PURPOSE:To accurately adjust sound volume and to reduce the cost of the title device by providing the device with a voltage divider for dividing respective input voltages so as to allow them to interlock with each other, a variable gain amplifier and a means for adjusting the input voltage of the voltage divider and supplying respective sound channel signal to the voltage divider and the variable amplifier. CONSTITUTION:When an operator depresses the I side pushbutton of a sound volume balance adjusting switch 6 while holding a main volume switch at a fixed position, the duty ratio of a PWM signal is reduced in accordance with the depression time and the number of times of depression. Thereby, the DC output voltage of an integrating circuit 11 is reduced and the signal level of an output sound channel signal 2 is dropped. At the time of depressing the II side pushbutton of the switch 6, the signal level of the signal 2 can be increased by increasing the duty ratio of the PWM signal. Thereby, the generation of a non-sensitive band at the low level position of the main volume can be prevented and gain can be finely adjusted.

Description

TECHNICAL FIELD The present invention relates to a volume balance adjustment device for adjusting the respective levels and relative levels of a plurality of audio channel signals.

BACKGROUND ART An example of a conventional volume balance adjustment device will be explained with reference to FIG.

In FIG. 3, when the operator turns the main volume knob 1 clockwise to increase the volume of a speaker (not shown), the first switch of the encoder 2 is turned on and off according to the rotation angle of the knob 1, and a count-up pulse is activated. Occur. This count-up pulse is generated by the microprocessor (
When the signal is supplied to an up/down counter of the volume control unit 3 (hereinafter simply referred to as MPU), the integrated value of the counter increases in accordance with the number of supplied pulses.

When the knob 1 is rotated counterclockwise to decrease the volume of the speaker, the second switch of the encoder 2 is turned on and off according to the rotation angle of the knob 1 to generate a countdown pulse. When this countdown pulse is supplied to the up-down counter mentioned above, the integrated value decreases according to the number of supplied pulses.

The MPU of the volume control unit 3 determines the volume specified by the main volume knob 1 by reading this integrated value, and determines the volume specified by the main volume knob 1 and the electronic volume 4 inserted into the first audio channel signal path and the electronic volume knob 4 inserted into the second audio channel signal path. The content of the gain control signal of the electronic volume 5 is set corresponding to the previously described integrated value.

Each electronic volume is integrated circuit, and is composed of a diffused resistor array and a group of analog switches.

The amount of attenuation of the electronic volume is set by turning on the analog switch corresponding to the content of the gain control signal. An example of such an electronic volume is Japanese Patent Application No. 62-208769.
Disclosed in the issue. Each audio channel signal that has passed through the electronic volumes 4 and 5 is converted into audio via a power amplification stage and a speaker (not shown).

In addition, when the operator presses the I side button switch or the ■ side button switch of the volume balance adjustment switch 6 to adjust the volume balance of each speaker, the volume balance adjustment switch 6 adjusts the suppression time of the button switch 6 or presses the button switch. A number of first or second offset pulses are generated depending on the number of times.

When the first offset pulse is supplied from the volume balance adjustment switch 6 by pressing the I-side bushing switch, the MPU described above adjusts the gain change characteristics of the electronic volume 5 with respect to the main volume indicated position according to the number of supplied pulses. Change the overall level so that it decreases. Furthermore, when the second offset pulse is supplied by pressing the bush switch on the ■ side, the gain change characteristic with respect to the main volume position of the electronic volume 5 is changed in a direction in which the overall level increases according to the number of supplied pulses. There will be a change. Such gain change characteristics are read out by executing a predetermined arithmetic expression or from a memory map in which the characteristics are stored in a memory (not shown).

Therefore, as shown in FIG. 4, the levels of the audio output signals of the electronic volumes 4 and 5 are set in accordance with the settings of the main volume knob 1 and the volume balance adjustment switch 6, respectively.

However, in such a configuration, the software for controlling each electronic volume becomes complicated, and a relatively expensive electronic volume is provided for each audio channel signal path, making the apparatus expensive. Also, due to the structure of the electronic volume, the volume setting is gradual, so fine adjustment is not possible. There is a problem that a dead zone may occur in which the output of the electronic volume does not follow changes in the low level indication range of the main volume knob 1.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a volume balance adjustment device that can perform fine volume adjustment and is relatively inexpensive.

In order to achieve the above object, the volume balance adjustment device of the present invention includes a voltage divider that divides each input voltage in conjunction with each other, and a variable gain amplifier whose gain changes according to the divided voltage output of one of the voltage dividers. and an adjustment means for adjusting the input voltage of the one voltage divider based on the balance setting signal, and is characterized in that it supplies each audio channel signal to each of the other voltage divider and the variable amplifier.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG. Components in the circuit shown in FIG. 1 that correspond to those in the circuit shown in FIG. 3 are given the same reference numerals.

In FIG. 1, when the I side push switch of the volume balance adjustment switch 6 is pressed, a number of first offset pulses are generated depending on the pressing time or the number of times the button is pressed. Similarly, when the ■ side bushing switch is pressed, a second offset pulse is generated.

The MPU of the volume control section 10 increases the integrated value of the internal counter by integrating the first offset pulse, and decreases the integrated value by using the second offset pulse. Based on this integrated value, for example, the MP that repeatedly operates
The timeout period of the internal timer of U is controlled to obtain a PWM signal in which the pulse width of the timer output is modulated.

The PWM signal is supplied to a refinement circuit 11 and converted into a voltage signal proportional to the duty ratio of the PWM signal. This voltage signal is amplified by a buffer amplifier 12 and supplied to one end of a resistor of a potentiometer 13a whose slider is interlocked with the main volume knob 1. The other end of the resistor is grounded, and the slider output as a divided voltage output becomes a gain control voltage of a voltage controlled variable gain amplifier (hereinafter referred to as VCA) 14.

Further, the slider of a potentiometer 13b having the same characteristics as the potentiometer 13a as a voltage divider is mechanically or electrically linked to the main volume knob 1, and the movements of the sliders of the potentiometers 13a and 13b are synchronized. ing. The input audio channel signal 1 is supplied to one end of the resistor of the potentiometer 13b, and the other end is grounded. The human input audio channel signal 1 voltage-divided by the resistance ratio of the slider becomes a level-adjusted output audio channel signal 1, which is supplied to the next stage audio output circuit (not shown). In addition to potentiometers, various level regulators can be used as voltage dividers.

The VCA 14 controls the level of the input audio channel signal 2 with a gain according to the gain control voltage described above, outputs the audio channel signal 2, and supplies the output audio channel signal 2 to the next stage audio output circuit (not shown).

Next, the operation of the apparatus will be explained with reference to FIG.

First, when the operator rotates the main volume knob 1 clockwise while the output of the amplifier 12 is constant, the potentiometers 13a and 1
3b decreases, and the levels of both output audio channel signals 1 and 2 as shown increase in proportion to the rotational position of the main volume knob 1. Similarly, rotating knob 1 counterclockwise will decrease the level of each output audio channel signal.

On the other hand, if the operator presses the ■ side switch of the volume balance adjustment switch 6 while keeping the main volume knob 1 in a fixed position, the PW will change depending on the pressing time or number of times.
The duty ratio of the M signal decreases, and the DC output voltage of the integrating circuit 11 decreases. This DC voltage is applied to one end of the potentiometer 13a via the amplifier 12, so the VCA
The gain control voltage of 14 is decreased and the signal level of the output audio channel signal is decreased.

Furthermore, when the I-side button switch of the volume balance adjustment switch 6 is pressed, the duty ratio of the PWM signal mentioned above increases, so the DC output voltage of the integrating circuit 11 increases, and is applied to one end of the potentiometer 13H via the amplifier 12. Voltage increases.

This increase in voltage increases the gain of the VCA 14 and increases the signal level of the output audio channel signal 2.

Therefore, the I side of the volume balance adjustment switch 6 or ■
By operating the side bushing switch, the signal level of the output audio channel signal 2 relative to the signal level of the output audio channel signal 1 can be changed toward the balance I side or the balance II side as shown.

In this way, the gain of the signal path of audio channel signal 2 increases or decreases as the gain of the signal path of audio channel signal 1 increases or decreases, and the rate of increase or decrease is controlled by the volume balance adjustment switch, so that when the main volume is There is no dead zone at the level position, and the gain can be finely adjusted. The control target of the MPU of the volume control unit 3 has been simplified from the conventional gain setting of two signal paths to the gain setting of one signal path, and the volume balance can be adjusted arbitrarily without changing the control program. It becomes easy to obtain the characteristics. Furthermore, since the relatively expensive electronic volume described above is not used, there is an advantage that the structure can be constructed at low cost.

Note that the output voltage of the amplifier 12 is directly supplied to the control input terminal of the VCA 14, the input audio channel signal 2 is supplied to one end of the potentiometer 13a, and the level-adjusted output is set to V.
It also functions as an input to the CA 14 in the same manner as in the previously described embodiments. Furthermore, a control voltage for balance adjustment controlled by the audio control unit 10 is supplied to the input end of the potentiometer 13b, and the slider output is used as the control voltage of the newly provided VCA to which the audio channel signal is supplied. can also be considered. This has the advantage of increasing the degree of freedom in setting the level of each channel signal.

In addition, in the embodiments, a device having two signal paths, such as a left and right volume balance adjustment device of a stereo playback device, is explained, but a device for adjusting the balance between front side signals and rear side signals in a surround playback device, etc. It is also applicable to adjusting the balance of signal levels in a device having two or more signal paths.

As described in detail, the volume balance adjustment device of the present invention includes another voltage divider mechanically or electrically linked to a voltage divider such as a potentiometer inserted into the audio channel signal path for volume adjustment. The level of the balance setting signal is adjusted by the adjustment level, and the gain of the VCA that sets the level of the other audio channel signals is controlled by the adjustment level, so that the level increase/decrease of each audio channel signal relative to the overall volume adjustment is mutually controlled. They are synchronized, and when further balance adjustment is performed, the level of the audio channel signal changes proportionally. Therefore, the volume can be adjusted finely, and the dead zone described above can be eliminated. In addition, such a configuration is relatively simple and the dependence on program control by the MPU is reduced, so it is possible to reduce the cost of the device and to obtain desired volume balance characteristics without changing the program. Become.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram for explaining the operation of the above embodiment, FIG. 3 is a block diagram showing a conventional example, and FIG. FIG. 2 is an explanatory diagram for explaining the operation of a conventional example. Explanation of symbols of main parts 1... Main volume knob 6... Volume balance adjustment switch] 0... Volume control section 13a, 13b... Potentiometer 14... Voltage controlled variable gain amplifier Applicant: Pioneer Corporation

Claims (4)

[Claims] (1) A voltage divider that divides each input voltage in conjunction with each other, a variable gain amplifier whose gain changes according to the divided voltage output of one of the voltage dividers, and a voltage divider of the one voltage divider based on a balance setting signal. A volume balance adjusting device comprising: adjusting means for adjusting an input voltage of the second voltage divider and the variable amplifier, and supplying each audio channel signal to each of the other voltage divider and the variable amplifier. (2) The volume balance adjustment device according to claim 1, wherein the voltage divider is a potentiometer, and the divided voltage output is a voltage generated on a slider of the potentiometer. (3) The adjusting means includes a signal generating means for generating a pulse width modulated signal having a pulse width according to the content of the balance setting signal, and a signal smoothing means for smoothing the pulse width modulated signal to obtain a DC voltage. 2. The volume balance adjustment device according to claim 1, wherein the DC voltage is an input voltage of the voltage divider. (4) Claim 1, further comprising an additional variable amplifier whose gain changes depending on the output of the other voltage divider, and the audio channel signal is supplied to the additional variable amplifier.
The volume balance adjustment device described.