SU789791A1 - Apparatus for measuring amplitude variation height - Google Patents

Description

one

The invention relates to electrical measuring equipment, in particular, to devices that allow to investigate the oscillation range of any of the parameters of a primary parametric electric converter included in an alternating voltage generator circuit, in whose circuits the amplitude modulation of the current is carried out by changing the parameter of the converter whereby the voltage on the elements of the generator circuit also experiences amplitude modulation, reproducing the nature of the change in the measured parameter.

A device for measuring the amplitude amplitude of an alternating voltage is known, which contains a peak detector and an adder connected to the inputs of the comparator unit, to the output of which are connected in series the element I, plug, pulse counter and recorder, reference frequency generator, frequency divider, discrete differentiator and digital-to-analog converter Ll.

When measuring the magnitude of the amplitude variation of the amplitude-modulated signal, use

the known device is possible after the detected signal. In this case, the output of the device will be a signal proportional to the difference of the amplitudes

5 of the tensioned voltage between adjacent maxima and minima, but it cannot distinguish between the maximum and minimum voltage values over the entire implementation period.

10 in view of the fact that the devices respond to the following extreme voltage values.

The closest technical solution to this invention is a device for measuring the magnitude of a change in the amplitude of oscillations, which contains two keys, a null organ, two peak detectors, which successively respond to increasing

20 and decreasing input voltage,

two emitter followers, from which the maximum and minimum voltages are output to the differential amplifier, and its output

25, the difference between these values, fixed by voltage clamp 2, is obtained. A disadvantage of the device is that when measuring the range of the amplitude variation of the amplitudes of the 30 modulated signal, it is necessary.

MOs perform the detection and filtering of the modulated signal, which increases the inertia of the devices and introduces distortions to the signal, which cause additional errors in the measurement. These errors are especially large when examining signals with sharp amplitude deviations from the mean value. The known device also gives the difference in amplitudes of the alternating voltage between adjacent maxima and voltage minima.

The purpose of the invention is to improve the accuracy when measuring amplitude-modulated oscillations.

The goal is achieved by the fact that the device is equipped with an amplifier of a carrier frequency of amplitude-modulated oscillations, the amplitude of oscillations at the output of which is greater than the maximum amplitude of the amplitude-modulated oscillations, the output of the amplifier is connected to the input of the second and third peak detectors, and the second subtraction unit, whose inputs are connected respectively, with the outputs of the second and third peak detectors, and the output with another input of the first subtraction unit.

The drawing shows a block diagram of a device for measuring the magnitude of a change in the amplitude of oscillations.

The device contains two amplifiers 1 and 2, three peak-acting detectors 3-5, the first and second subtraction blocks 6 and 7, and voltage clamp 8.

An amplitude-modulated oscillation is fed to the input of amplifier 1 from one of the circuit elements to which the modulation is carried out. The input of amplifier 2 is the voltage from the generator feeding this circuit (voltage of the carrier frequency of an amplitude-modulated oscillation).

These voltages are amplified by amplifiers mIi 1 and 2 and fed to three detectors: to detector 3 — modulated voltage, to detector 4 — voltage from the generator, and to detector 5 — voltage difference between the generator and modulated voltage, which is positive, which provides a large gain of amplifier 2 compared to the gain of amplifier 1.

In the second subtraction unit 7, the voltage taken from the detector 5 is subtracted from the voltage supplied from the detector 4. Next, the resulting difference is subtracted from the voltage output from the detector 3 output by the first subtraction unit 6.

A control voltage proportional to the magnitude of the change in the amplitude of the oscillations is applied to the voltage clamp 8.

As the first and second blo. For subtracting 6 and 7, which produce operation U. - (U), a device of double algebraic summation can be used, for example, on the basis of an operational amplifier that performs the operation and + UZ.- and id - (Uj-).

The invention measures the difference in voltage amplitudes between their minimum and maximum values during implementation, which allows us to investigate fast processes and expand the scope of use of the device in the field of electrical measurements of linear quantities, namely to measure the range of micro-surface roughness, film thickness width of the gap between the surfaces of moving machine parts.

Claims (2)

1. Author's certificate number 42829U, cl. G 01 R 19/04, 11.07.72. 2. The copyright certificate 427288, cl. G 01 R 19/04, 07.02.72.