SU842697A1 - Device for comparing two ac voltages - Google Patents

Description

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The invention relates to a measurement technique, is intended to compare two alternating voltages with equal frequencies and can be used in non-contact sensors for non-destructive testing, with comparative measurements produced by two sensors, in orientation systems, as well as in detection and detection systems.

A device for comparing signals is known, consisting of two input circuits, a subtraction unit, which provides for the separation of the difference between the apparent voltages Cl

The disadvantage of this device is low sensitivity and speed.

The closest in technical essence to the present invention is a device for comparing two alternating voltages, which is a single-channel device containing a switch for alternating voltages.

connections of the compared voltages to the measuring circuit, including c. se amplifier, synchronous detector, switching generator, phase-sensitive detector, filters and subtraction unit G21.

A disadvantage of the prior art device is the narrow dynamic range of measurements, since with a large level of input signals the amplifier enters saturation mode, and with a small difference in amplitude of input signals due to saturation of the amplifier, their comparison is not possible.

The purpose of the invention - the expansion of the dynamic range and poyvenie sensitivity.

The goal is achieved by the fact that the device containing the amplifier, the subtraction unit connected to the recorder, is equipped with two integrators, a first limiter on top, connected between the first input terminal and the amplifier input, the first

a lower limiter whose input through the phase shifter is connected to the second input terminal, and an output to the amplifier input, the second upper limiter, is connected between one of the amplifier outputs and the first integrator input, the second LOWER limiter connected between the other amplifier output and the second integrator's input The output of the integrators is connected to the subtraction unit.

FIG.} Is a block diagram of the device; in d.2, the eshores a, b, and stresses at the output of individual functional units of the device.

The device contains input terminals I and 2, the limiter 3 on top, the phase shifter 4. The phase shifter 4 through. The limiter 5 is connected below with an amplifier 6, one of whose outputs is connected in series by a limiter 7 on top and an integrator in, the other is a limiter 9 and an integrator 10. The outputs of the integrators 8 and 10 are connected to the jI subtraction unit 12 connected to the recorder 12 .

The device works in the following way.

One of the compared voltages is limited by the limiter 3 to the input of the amplifier 6. The other compared signal through the phase shifter 4, which equalize the phases of the compared signals, goes to the limiter 5. The signals from the outputs of the limiters 3 and 5 (fig.2a) are fed to the input of the amplifier 6. After amplification, the signal from one of the inputs of amplifier 6 goes to limiter 7, bounding it from above, and accumulates in integrator 8 (FIG. 2b), and from the other output of amplifier 6 goes to limiter 9, limiting its order, and accumulates with jB integrator 10 figv. The signals from the outputs of the integrators 8 and 10 are fed to the inputs of the I1 subtraction block I1, the difference is recorded by the recorder 12.

The present invention makes it possible to compare voltages of fast processes with an accuracy of 0.1% of the MOCR® frequency range from 1 kHz to 10 MHz,

Claims (2)

1. Author's certificate of the USSR 130115, cl. G 01 R 19/10, 1958. 2. Authors certificate of the USSR N 661494, cl. G 03 B 1/01, 1977. P n r