JPH0722902Y2 - Volume control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a volume adjusting device used for an audio amplifier or the like, and more particularly to a volume adjusting device for adjusting the volume of a multi-channel signal in conjunction.

[Prior Art] In an audio system or an audio video system, there is a reproducing method for obtaining a rich sound field space by arranging speakers in the front center and the rear in addition to the normal left and right two-channel stereo and reproducing speakers. .
FIG. 4 shows an example of such a surround system, and speakers SP1 to SP5 are arranged at the front left, front center, front right, rear left, and rear right of the reproduced sound field. Input terminals 1 to 5 are supplied with signals of 5 channels respectively, and the volume 6
And an amplifier 7 to supply each speaker. Adjust the volume 6 to adjust the volume of the signal of channel 5 in the same way.
Is a mechanical volume that works together. The mechanical volume has no problem in electrical characteristics, but when the number of interlocking stages is increased, the rotational torque becomes large, and the interlocking error becomes large due to variations in printing resistance and structural reasons. Furthermore, the cost increases as the number of interlocking stages increases. On the other hand, there is an electronic volume as the volume. Although there are various configurations of the electronic volume control, one of them is a combination of a plurality of resistors and an analog switch, which is configured to open / close the analog switch with a digital control signal to attenuate the signal to a desired voltage value. Although the electronic volume has few interlocking errors and can be controlled in multiple stages, it has problems in electrical characteristics such as distortion, dynamic range, and SN ratio.

[Problems to be solved by the device]

As a volume control device that adjusts the volume of multiple channel signals in a surround system, there are a case where a mechanical volume as described above is used and a case where an electronic volume is used. Here, a mechanical volume and an electronic volume are used. It is conceivable to use together with and to provide a volume adjusting device in which the influence of the above-mentioned drawbacks of both volumes is reduced.
That is, the mechanical volume is used for the channels that place importance on electrical characteristics, and the electronic volume is used for the other channels. For example, in a 5-channel surround system as shown in FIG. 4, a mechanical volume control is used for the front left and right front channel signals which are normal left and right stereo, and is provided to increase other effects. An electronic volume control is used for the front center, rear left, and rear right channel signals. However, when the mechanical volume and the electronic volume are used together in this way, there is a problem that the interlocking error between the mechanical volume and the electronic volume becomes large, and it is difficult to adjust the volume of each channel equally. An object of the present invention is to provide a volume adjusting device that uses a mechanical volume and an electronic volume together and reduces the interlocking error.

[Means for Solving the Problems]

 The means of the present invention are as follows.

The reference voltage supply means is one of the plurality of electronic volume controls that interlock with the plurality of interlocking mechanical volume controls.
Supply the reference voltage to the input terminals of the two volume controls. The comparison means compares the voltages at the output terminals of the mechanical volume and the electronic volume supplied with the reference voltage. The control means receives the output of the comparison means and outputs a control voltage to simultaneously control the plurality of electronic volume controls.

[Action]

By the above means, the electronic volume supplied with the reference voltage, the comparison means and the control means form a closed loop, and the voltage at the output terminal of the mechanical volume which is one input of the comparison means is fed back as the reference voltage. Since the operation is performed, the output terminal voltages of the mechanical volume and the electronic volume match. Therefore, the interlocking error between the mechanical volume and the electronic volume is eliminated.

〔Example〕

An embodiment will be described below with reference to FIGS. 1 to 3.

FIG. 1 shows a volume adjusting device for transmission channels CH1 to CH5 of a 5-channel signal. MVR1 to MVR3 are interlocking mechanical volumes, and EVR1 to EVR4 are interlocking electronic volumes. Of these, the mechanical volume MVR3 and the electronic volume
A reference voltage 11 is applied to the input terminals a and b of the EVR1, and the voltages of its output terminals c and d are input to a comparator 12 for comparison. The comparator 12 outputs the difference voltage between the two input voltages and gives it to the controller 13. The controller 13 gives a control output proportional to the output of the comparator 12 to the electronic volume EVR1 to control its output voltage. As a result, the electronic volume EVR1 is controlled so that the output voltage of the electronic volume EVR1 becomes equal to the output voltage of the mechanical volume MVR3. The output of the controller 13 is also given to the other electronic volume controls EVR2 to EVR4, so the mechanical volume controls MVR1 to MVR3 and the electronic control volume EVR1 to
EVR4 will work together without error.

Electronic volume is roughly classified into analog type and digital type. Controller 13 depending on the type of electronic volume used
Although the internal configuration is different, the other configurations in FIG. 1 are the same.

FIG. 2 shows an electronic potentiometer composed of seven resistors R1 to R7 and eight C-MOS analog switches TG1 to TG8. The input voltage applied to the input terminal 20 is output from the output terminal 21 after being attenuated by the resistance ratio when one of the analog switches TG1 to TG8 is closed. FIG. 3 shows a second electronic volume EVR1 to EVR4.
It is an example in the case of using the digital electronic volume shown in the figure. One of the interlocking mechanical volume MVR3
A reference voltage 30 is applied to each input terminal of EVR1, which is one of the electronic volume controls linked with. Since the voltages at the output terminals c and d of both volumes are input to the inverting input terminal and the non-inverting input terminal of the differential amplifier 31, the differential amplifier 31 amplifies and outputs the difference voltage between the input voltages. The output voltage of the differential amplifier 31 is input to the analog-digital conversion circuit 32 and converted into a digital voltage. Since there are eight analog switches for each of the electronic volume controls EVR1 to EVR4 in this example,
The analog-digital conversion circuit 32 outputs a 3-bit digital voltage and inputs it to the decoder circuit 33. Decoder circuit 33
Has eight output terminals corresponding to eight analog switches, one of which produces an output due to an input digital voltage and closes one of the eight analog switches. That is, the decoder circuit 33 outputs the 3-bit input digital voltage to 8
Decode into one output. These eight outputs are added in parallel to the electronic volumes EVR1 to EVR4, so that the volumes are linked. The differential amplifier 31 corresponds to the comparator 12 in FIG. 1, and the analog-digital conversion circuit 32 and the decoder circuit 33 correspond to the controller 13. Electronic volume EVR1,
Since the differential amplifier 31, the analog-digital conversion circuit 32, and the decoder circuit 33 form a closed loop, the electronic volume EVR1 is controlled by the output of the decoder circuit 33 so that the output voltage of the differential amplifier 31 becomes zero. . Therefore, the voltage of the output terminal c of the mechanical volume MVR3 and the voltage of the output terminal d of the electronic volume EVR1 are always equal. Thus, mechanical volume MVR1-MVR3 and electronic volume EV
R1-EVR4 will work together without error.

As described above, the present invention compares one output voltage of each of a mechanical volume and an electronic volume that are interlocked with each other, and controls the electronic volume with the comparison output. It may be an analog type composed of a voltage controlled amplifier controlled by a voltage, in which case the controller is composed of an amplifier.

[Effect of device]

Since the voltage of each output terminal of the mechanical volume and the electronic volume to which the reference voltage is applied is always the same, the interlocking error of both volumes can be eliminated. Therefore, in one surround system, the mechanical volume can be used only for the channels that place importance on electrical characteristics, and the volume can be adjusted in conjunction with the other channels by using the electronic volume. Therefore, since the mechanical volume having a small number of stages is sufficient, the rotational torque of the mechanical volume can be reduced, and the interlocking error due to the structural cause can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a volume control device of the present invention, FIG. 2 is a diagram showing an example of a digital electronic volume control, FIG. 3 is an embodiment diagram when a digital electronic volume control is used, and FIG. It is a figure which shows the conventional volume control apparatus. MVR1 ~ MVR3 ... interlocking mechanical volume, EVR1 ~ EVR4 ...
Interlocked electronic potentiometer, 11 …… reference voltage, 12 …… comparator, 13 …… controller.

Claims (1)

[Scope of utility model registration request] 1. A plurality of interlocking mechanical volumes, a plurality of interlocking electronic volumes, a reference voltage applied to each input terminal of each one of the mechanical volume and the electronic volume, and the reference. A comparator for comparing output terminal voltages of a mechanical volume and an electronic volume to which a voltage is applied; and a controller for receiving the output of the comparator and controlling the plurality of electronic volumes. Volume control device.