JPH0215386Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electronic volume that can be used in common with a loudness control circuit and an electronic fader circuit. Regarding the electronic volume formed by

[Technical background and problems of the invention]

A conventional loudness control circuit was constructed as shown in FIG. 1, for example. In Fig. 1, 1 is the main body of the volume that operates in 10 dB steps, and voltage dividing resistors _10-1 ,...10- _o connected in series.
and electronic switching means _11-1 , . . . 11- _o , each of which has one end connected to one end of voltage dividing resistors _10-1 , . . . 10- _o , and whose other end is commonly connected. 2 is a volume main body that works in 1 dB or 2 dB steps, and like the volume main body 1, voltage dividing resistors _12-1 ,...12- _o are connected in series, and one end is connected to the voltage dividing resistors _12-1 ,...12- _o , respectively. It consists of electronic switch means _13-1 , . . . 13- _o connected at one end and commonly connected at the other end. Reference numeral 3 designates a buffer amplifier which receives the output from the volume body 1 as an input, supplies the output to the volume body 2, and performs matching between the volume bodies 1 and 2. 4 is a two-channel multiplexer whose common terminal is connected to the tap on the volume body 1, and 5 is an external capacitor for loudness.
6 indicates a resistance for loudness. Note that 7 indicates an electronic volume.

The signal supplied to the input terminal IN is applied to the volume body 1 via the input terminal IN, and is also applied to the capacitor 5-1 and the multiplexer ₄ connected between one equivalent contact _4-2 of the multiplexer 4 and the input terminal IN. It is also applied to a series circuit with a capacitor _5-2 and a resistor ₆ connected between equivalent contacts 4-1 and _4-2 . The output of the volume body 1 is applied to the volume body 2 via the buffer amplifier 3,
It is configured so that the output of the volume main body 2 is led out to the output terminal CUT.

In the conventional loudness control circuit configured as described above, loudness control is performed when the equivalent contact _4-1 of the 2-channel multiplexer 4 is off and the equivalent contact _4-2 is on, and high-frequency boost characteristics are applied at high frequencies. shows,
At low frequencies, it exhibits low-frequency boost characteristics. Further, when the equivalent contacts _4-1 and _4-2 are controlled to a normal state, no loudness control is performed and a flat frequency characteristic is exhibited.

On the other hand, the fader circuit, which has two output terminals per channel for audio input signals and changes the balance of the output signals from the two output terminals, is similar to the volume main body 1 as shown in Fig. 2a. The configured volume 8 is connected, and the output terminal is connected to the input terminal via a resistor. Alternatively, a variable resistor may be connected between each of the two output terminals and the ground. In this case, as shown in FIG. 2b, the electronic volume 7 shown in FIG. An electronic volume 7' having a similar structure can be connected to the input terminal. Note that in this case, terminals A and B are short-circuited. Therefore, electronic switching means _11-1 for volume 8, electronic volume 7, 7A, . . .
By controlling 11- _o , _13-1 , . . . 13- _o , the balance of outputs from the two output terminals can be changed.

However, although the main components of the above-mentioned loudness circuit and fader circuit are almost the same, they each have the disadvantage that they are constructed independently and can only be used for their respective purposes. Also, when creating an integrated circuit, the mask pattern is
There were some drawbacks that made it necessary. Furthermore, when only the volume body is integrated into an integrated circuit, the multiplexer has to be externally attached, which increases the number of peripheral circuits, which has the disadvantage that the integrated circuit becomes meaningless.

[Purpose of invention]

The present invention has been made in view of the above, and it is an object of the present invention to provide an electronic volume that eliminates the above-mentioned drawbacks and can include a loudness circuit and a fader circuit in the same integrated circuit.

[Example of idea]

FIG. 3 is a circuit diagram showing the configuration of one embodiment of the present invention, and FIG. 4 is a circuit diagram showing details of a multiplexer in one embodiment of the present invention.

In one embodiment of the present invention, the volume main body 1, the volume main body 2, and the resistor 6 are integrated, and one end of the voltage dividing resistor forming a part of the volume main body 1 forms a part of the volume main body 2. one end of the sub-pressure resistor, one end of the resistor 6, a common connection point of the electronic switch that forms a part of the volume body 1, a tap on the volume body 1, and a common terminal of the electronic switch that forms a part of the volume body 2. are respectively connected to external connection terminals a to f. The other ends of the volume bodies 1, 2 and the resistor 6 are connected in common and connected to an external connection terminal k.

Furthermore, a two-channel multiplexer is connected to the analog switches _4-1 to _4-4 as shown in FIG.
It is composed of This analog switch _4-1 ~
_4-4 and an inverter _4-5 for driving the analog switch are integrated, and the input end of the analog switch _4-2 and the input end of the analog switch _4-3 are commonly connected to the outside. g
In addition, the input end of analog switch _4-1 and the input end of analog switch _4-4 are connected to the external connection terminal h, and the output end of analog switch _4-1 and the output end of analog switch _4-2 are connected to the external connection terminal h. The output terminal of analog switch _4-3 and the output terminal of analog switch _4-4 are commonly connected to external connection terminal i, respectively, and analog switches 4-1 _{to 4-1} are connected to common external connection terminal i. The control signal for controlling _4-4 is directly supplied to analog switches _4-1 and _4-3 , and the control signal is inverted and supplied to analog switches _4-2 and _4-4 by inverter _4-5 . be. Note that 1 is a control signal terminal to which a control signal is supplied.

In one embodiment of the present invention constructed as described above, the signal supplied to the input terminal is supplied to the connection terminal c as shown in FIG.
− ₁ to connection terminal g. Connection terminal i
The output from is supplied to connection terminal b. Connection terminal a
and b, a capacitor _5-2 , connecting terminals d and e
A buffer amplifier 3 is connected between the two.

As is clear from a comparison of the circuit with the connections shown in FIG. 5a and the circuit in FIG. 1, FIG. 5a constitutes the same loudness circuit as in FIG. 1.

Next, as shown in FIG. 5b, the signal supplied to the input terminal is supplied to connection terminals c and g, connection terminals a and b are connected, and connection terminals f and h are connected. Note that the buffer amplifier 3 has connecting terminals d and e.
The connection terminals i and j each supply an output as an output terminal.

On the other hand, in the fader circuit, the two outputs are controlled independently, but considering the situation where it is not necessary for both to be attenuated outputs, the signal before the attenuation operation and the signal after the attenuation operation are extracted and these two signals are The applicant has already proposed a circuit that selectively outputs to two output terminals, and this circuit is as shown in FIG. Input signals are supplied to the volume body 1, switches _9-2 and 9'- ₁ . The output of the volume body 1 is supplied to the volume body 2 via the buffer amplifier 3, and the output of the volume body 2 is supplied to the switches _9-1 and _9' - ₂ .
The output of switch 9'- ₂ is output A, and the output of switches 9'- ₁ and 9'- ₂ is output B.

Therefore, in the fader circuit shown in Fig. 6,
When switches _9-1 and 9'- ₂ are turned on and switches _9-2 and 9'- ₁ are turned off, the signal supplied from the input terminal is not attenuated from output A and remains at the same level. and output B
is output at a level attenuated by volume bodies 1 and 2. Also, switch _9-1
When switches 9'- ₂ and 9'- ₂ are turned off and switches 9-2 and 9'- ₁ are turned on, the signal supplied from the input terminal is not attenuated and is output as is to output B; Output at attenuated level. As a result, according to the fader circuit shown in FIG. 6, the characteristics shown in FIG. 7 can be obtained. In FIG. 7, the solid line indicates output A, and the broken line indicates output B. In section C, switches _9-1 and 9'- ₂ are on, switches _9-2 and 9'- ₁ are off, and section C is In D, switches _9-2 and 9'- ₁ are on and switches _9-1 and 9'- ₂ are off.

In a fader circuit, one of the two outputs is always 0dB
output and the other is the output of the damping operation, both
Figure 7 shows that the characteristics change after 0 dB output.

On the other hand, as is clear from a comparison between FIG. 5b and FIG. 6, the circuit of FIG. 5b constitutes the same fader circuit as that of FIG. 6, and performs a fader operation.

[Effect of idea]

As explained above, according to the electronic volume of the present invention, since two volume bodies and a two-channel multiplexer are independently integrated on the same chip, it can be applied to both loudness circuits and fader circuits. Furthermore, there is no need to prepare two types of mask patterns for integration, and there is no need to use an external multiplexer, so the peripheral circuitry of the integrated circuit does not become complicated.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a conventional loudness circuit, FIG. 2 a and b are circuit diagrams showing the configuration of a conventional fader circuit, and FIG. 3 is a circuit diagram showing the configuration of an embodiment of the present invention. FIG. 4 is a circuit diagram showing the configuration of a multiplexer in an embodiment of the present invention;
Figure a is a circuit diagram of a loudness circuit constructed according to an embodiment of the present invention, Figure 5b is a circuit diagram of a fader circuit constructed according to an embodiment of the present invention, and Figure 6 is a circuit diagram of a fader circuit constructed according to an embodiment of the present invention.
The figure is a circuit diagram of a fader circuit proposed by the present applicant, and FIG. 7 is a characteristic diagram of the fader circuit of FIG. 6. 1 and 2...Volume body, 3...Buffer amplifier, _4-1 to _4-4 ...Analog switch,
_5-1 and _5-2 ... Capacitor.

Claims (1)

[Scope of utility model registration request] first and second volume bodies each consisting of a voltage dividing resistor in which a plurality of resistors are connected in series; a switch means having one end connected to one end of the plurality of resistors and the other end connected in common; and two channels. 1. An electronic volume comprising a switch means constituting a multiplexer and integrated on the same chip.