SU538486A1 - Time-impulse transducer for resistive sensors - Google Patents

Description

(54) TIME-PULSE CONVERTER FOR RESISTANT SENSORS

Whose amplifier, in the feedback circuit of which the capacitor is included.

The drawing shows a f} a time-pulse converter for resistive sensors.

The time-pulse converter contains a differential integrator, a comparing device 2, executed on an operational amplifier, an exemplary sensor 3, a resistive sensor 4, an integrator 5 made on an operational amplifier, and a capacitor 6.

A resistive sensor with resistance R is connected between the output of the differential integrator 1 and the non-inverting input of the amplifier of the comparator device 2, at the positive feedback of which a sample resistor with resistance is included. The output of the amplifier is connected via an integrator 5 with a non-inverting input of the differential integrator I and directly with its inverting input. The capacitor 6 connects the output of the amplifier of the comparison device 2 to the summing point of the differential integrator 1.

During converter operation, the polarity voltage drops from the output-amplifier of the comparator device 2 go directly to the integrating input of the differential integrator, through the capacitor b to the inverting input of the amplifier of the integrator 1 and through the integrator 5 to the non-inverting input of the differential integrator 1.

The amplifier of the comparator device 2 is kept in saturation by means of positive feedback through the reference resistor and is triggered when the sawtooth voltage is equal with the integrator 1 threshold.

In this case, the sign of the output voltage of the amplifier of the comparator device 2 changes and, accordingly, the sign of the slope of the linearly varying voltage of the integrator 1. One half period T / S of the converter operation is described by the expression

2U - -2ui2. (7l. And 0 ° s

where UQ is the saturation voltage of the amplifier of the comparator;

f is the integrator time constant 5.

RI Cj is the time constant of the differential integrator 1.

CQ is the capacitance value of the capacitor 6.

In the most general case, the non-linear dependence of RX on its variable parameter D can be represented in the following way:

l x R- -RAX + BA,

Therefore, in order to provide a linear dependence of t on Jt, it is necessary to fulfill the following conditions:

C - C

but

In this case, the oscillation period will be determined by

AK

0

As can be seen from the expression, the transformation function of the device under consideration is linear with respect to parameter A. In the proposed device, the possibilities are quite simple, by appropriate selection of parameters, to improve the accuracy by correcting the non-linearity error.

Claims (2)

The invention is a time-pulse converter for emergency sensors containing a differential integrator, one input. which is connected to the output of a comparison device, implemented on an operational amplifier, and through a metering capacitor - to the same input of a differential integrator amplifier, the second input of which is connected to the output of the second operational amplifier, a resistive sensor and an exemplary resistor, different in that device, in it a resistive sensor is connected between the output of the differential integrator and the input of the comparing device, the reference resis is included in the feedback circuit of which op, and an output through the resistor coupled to the input of the second operational amplifier, a feedback circuit is switched capacitor. Sources of information are considered in the examination: i- EBectronic En -ineer-ing, October, 1972 (equivalent). 2. Copyright certificate for the ke-ke 2120680/2 from 04/01/1975