SU440676A1 - Device for raising to a whole positive degree the ratio of two input signals - Google Patents

Description

one

This invention relates to automation and computing.

Devices are known for raising to a whole positive degree the ratio of two input signals, comprising a main photoresistive bridge circuit, the photoresistor of which is optically coupled to a light source connected to the output of the differential amplifier, the inputs of which are connected to the first diagonal of the bridge circuit; One of the inputs of the differential amplifier is connected through a resistor to the first input of the device, the second input of which is connected to one of the second diagonal of the bridge circuit.

The proposed device differs from the known ones in that additional photoresistive bridge circuits are introduced in it, the photoresistors of which are optically coupled to. a light source, the other terminal of the second diagonal of the main bridge circuit is connected to the corresponding terminal of the second diagonal of the second bridge circuit, the second terminal of which is connected to the third output of the device, the first diagonal of the first additional and all subsequent odd bridge circuits are connected to the corresponding diagonals of each even even bridge circuit and connected to the four outputs of the device, and the second diagonal of the second additional and all subsequent even bridge circuits are connected to the corresponding diagonal of each of the following odd bridge circuits and connected to the odd outputs of the device.

This makes it possible to increase the accuracy of the work, expand the field of application and simplify the device.

The drawing shows a block diagram of the device.

The device contains photoresistive bridge circuits with photoresistors 1, 2, 3, 4. 5, light source 6, differential amplifier 7, resistors 8 and works as follows.

When input voltages Ux, Uy and f / z are applied, the outputs of the bridge circuits form a voltage of 17 (X, - / 7p.j, equal to

U ,, K, R, Uy U, K, R, U, I a.C, A / .f / ,.

(1) U ,,,., U ,, K, R, U,

where Ai /, ... are the changes in the resistance values of the photoresistors 1-5, respectively;

/ (l / Sa, ... - constructive constant coefficients of bridges.

Taking into account the on-source switching-on of the source Ux at the first input of the device with the output voltage of the bridge lJy and taking into account the presence of deep negative feedback formed by the circuit of the light source 6 - photoresistor 1, with a sufficiently large gain of the differential amplifier 7, it can be assumed that the illumination of the photoresistor 1, which is the ratio

a ,, and or and., - / CiA / ii / y (2)

Assumed to change the resistance values of photoresistors 1-5 at the same lightness equal to (or proportional to some constant values)

A ;, AJ., Aj, Ay ,, zA /, (3)

which is quite feasible with high accuracy while making them according to planar technology for the output voltages of bridges, solving together (1) and (2) you can get

  g 7 K-tK

to.

and,,

f / v

JJ K, G7

- 1 (uj

Using the / g + 1 bridge circuit, the outputs of the device can be obtained

KrK ,, .. Ki p / i

(four)

-i / v

to KI

(1 g l),

i.e., the device reproduces complex functional dependencies, which are the product of the scaling voltage and the ratio of the power functions Ux and Ug. In this case, as follows from the expressions obtained, the output signals of the device do not depend on the nonlinear properties of the optocoupler source of light — the photoresistor. At the same time, the scheme, when exposed to external destabilizing factors (including temperature), compensates them.

Indeed, accepting the changes in the constructive constants Kz, Kz Ki, which are approximately equal under the influence of destabilizing factors, and we can study equation (4) that

/ Cj / Ca-. -Ki

one.

/ C1

The described device can be performed

fully according to a single planar technology

which allows to significantly reduce the size and

power consumption of the device, increase

reliability and accuracy of conversion.

Subject invention

A device for raising to a whole positive degree the ratio of two input signals, containing the main photoresistive bridge circuit, the photoresistor of which is optically coupled to a light source connected to the output of the differential amplifier, the inputs of which are connected to the first diagonal

The main bridge circuit, one of the inputs of the differential amplifier, is connected through a resistor to the first input of the device, the second input of which is connected to one of the second diagonal of the main bridge circuit, characterized in that, in order to improve the operation accuracy and simplify the device, additional photoresistive bridge circuits whose photoresistors are optically coupled to the light source, and

Another terminal of the second diagonal of the main bridge circuit is connected to the corresponding clip of the second diagonal of the first additional bridge circuit, the second clamp of which is connected to the third input of the device, the first diagonal of the first additional bridge and all subsequent odd bridge circuits are connected to the corresponding even diagonal bridge circuits and connected to the even outputs of the device,

and the second diagonal of the second additional and all subsequent even bridge circuits are connected to the corresponding diagonal of each odd bridge circuit following it and connected to the odd outputs of the device.

.