JPS5921073B2 - Multiplication/division circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplication/division circuit that can obtain an output signal as represented by -■1 when there are three signals ■1, ■2, and ■3, and particularly, A target signal can be easily obtained with a simple configuration.

Hereinafter, a multiplication/division circuit according to the present invention will be explained with reference to the drawings.

FIG. 1 is an example of this, in which the first resistor R1 and the drain-source of the first field effect transistor 1 are connected in series,
A positive first signal (1) is supplied across the series circuit.

In addition, the second resistor R2 and the second field effect transistor 2
are connected in series, and a positive second signal V2 is supplied across the series circuit.

Furthermore, a comparison amplifier 3 is provided, one input end of which is supplied with a positive third signal V3, and a connection point between the second resistor R2 and the second field effect transistor 2 at its + side input end; That is, the obtained signal is supplied to the drain of the second field effect transistor 2, while resistors R3 and R4 are connected in series between the gates of the first and second field effect transistors 1 and 2, and a comparator amplifier is connected. 3 output signals are supplied to the connection point of these resistors R3 and R4.

However, it is necessary that ■2>■3. In this case, the first
The values of the second resistors R1 and R2 are approximately equal to each other.

Further, the first and second field effect transistors 1 and 2 are of N-channel junction type, and both have substantially the same characteristics of gate voltage versus drain-source resistance.

and a first resistor R1 and a first field effect transistor 1
The output signal V is output from the connection point of , that is, the drain of the first field effect transistor 1 .

is taken out.

In this circuit, if the drain-source resistances of transistors 1 and 2 are rllr2, then transistors 1 and 2
The signal V obtained at the drain of.

. ■Yes, each It is expressed as

When the signal vA obtained at the drain of this transistor 2 is smaller than the third signal V3, the comparison amplifier 3
The output voltage vB of becomes negative and works to increase the drain-source resistance r2 of the transistor 2 to make the signal vA stronger. Conversely, when the signal I is larger than the third signal I3, The output voltage VB of the comparison amplifier 3 becomes positive,
Since it works to reduce the resistance r2 between the drain and source of the transistor 2 and reduce the signal V force, the signal V
A follows the third signal 3 and becomes equal to it.

Therefore, from becomes.

and the gate voltage of transistors 1 and 2 vs. drain -
Since the characteristics of the source-to-source resistances are approximately equal and the gate voltages of transistors 1 and 2 are equal, the following equation is obtained.

Therefore, from equations (5) and (1), the output signal ■.

is, and since R1=R2, becomes.

That is, the output signal V.

is obtained by dividing the first signal (1) by the second signal (2) and multiplying it by the third signal (2).

By using the multiplication/division circuit described above, it is possible to easily control the volume of an electronic musical instrument using a constant envelope when operating a keyboard, etc., and apply volume vibrato at the same time.

That is, as the above-mentioned first signal (1), a waveform obtained from a synthesizer or the like that exhibits a certain timbre as shown in the figure is supplied that is continuously repeated at a frequency corresponding to the selected scale, and the second signal As the signal V2, a sine wave with a period corresponding to the selected scale (larger than that of the first signal 1) is supplied, and as the third signal v3, the rise is steep in the case of high notes, If we supply an envelope waveform that is gentle for bass sounds, the output signal V will be generated as shown in Figure 2.

In the end, the amplitude of the signal V1 is modulated by 1), and when this is supplied to the speaker 2, the volume gradually increases and vibrato is applied.

According to the multiplication/division circuit according to the present invention described above, multiplication/division operations can be performed using only a few transistors and resistors.

Note that the transistor is not limited to a field effect transistor, and a bipolar transistor can also be used.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram of one row of multiplication/division circuits according to the present invention, and FIG.
The figure is a waveform diagram for illustration purposes only. Ro and R2 are first and second resistors, 1 and 2 are first and second transistors, and 3 is a comparison amplifier.

Claims (1)

[Claims] 1. A first resistor and a first transistor are connected in series, and a first signal V1 is supplied between both ends of the series circuit,
a second resistor whose resistance value is approximately equal to that of the first resistor;
transistors are connected in series, a second signal (2) is supplied across the series circuit, and the voltage obtained at the connection point of the second resistor and the second transistor is a third signal (3). The comparison error signal is supplied to the control electrodes of the first and second transistors so that the voltage obtained at the connection point is equal to the third signal (3). The resistance of the current path of the transistor No. 2 is controlled, and the connection point of the first resistor and the first transistor No. 3 is controlled! ? A multiplication/division circuit configured to obtain a signal represented by -V, 2.