SU561146A1 - Phase meter - Google Patents

Description

one

The invention relates to electrical measuring equipment, may be used in phase-measuring devices.

A half-wave phase meter is known, containing in each channel a pulse shaper along zero-signal transitions, the output of which is connected to the indicator l.

The disadvantage of this phase meter is the large error in the nonlinear distortion of the input signals.

A full-wave phase meter is known, containing two level discriminators in each channel, the outputs of which are connected to the inputs of two triggers, are located for both channels, and the outputs of the triggers are connected to indicator 2.

The error caused by even harmonics in the input of the first signal is much smaller for such a phase meter than for a single half-period, and the error caused by odd-mode harmonics is the same.

The invention is a reduction in the errors of the phase meter, which are called by the even rafimic input signals.

This goal is achieved due to the fact that a known phase meter containing two channels, two level discriminators in each of the channels whose inputs are connected

with the inputs of two triggers common to both channels, and the outputs with an indicator, an amplifier with automatic gain control, two additional triggers, for each, are introduced. channels, and the amplifier

with automatic; adjusting the gain of each channel is connected to the inputs of the first, second, third, and fourth discriminators of the levels of its own channel, fixing, respectively, the moments of passage

signal in each channel through the levels corresponding to the phase angles of the input gar N OHH4ecKoro signal 30, 150, 210, 330, outputs t) of this and the fourth discriminator of the levels of each channel are connected to

the inputs of the third and fourth triggers, and the outputs of the latter are connected to the indicator.

Claims (2)

The drawing shows the block diagram of the phase meter. 35 Phase meter contains amplifiers 1 and 2 with automatic gain adjustment, displacement level gages, output three1 11-14, indicator 15. Amplifiers 1 and 2 provide a constant signal level at the discriminator inputs when changing the amplitudes of the input signals at the inputs a and b within the set limits of the working range of the amplitudes of the phase meter The discriminators 3 and 7 produce short pulses when the increasing portion of the positive half-wave reaches a level equal to half the amplitude of the output voltage of the amplifier. Ators 4 and 8 produce pulses at the moments of coincidence of the signal in the falling portion of the positive half-wave with the same level.Discriminators 5, 9 and 6, 10 produce pulses at the time of coincidence of the level of the signal with the negative pil-wave with a level equal to half of their amylttods in the increments reduction of negative voltage. Iculsals from discriminators 36 are triggered respectively by triggers 11-14, and pulses from discriminators 7-10 are respectively triggers triggered. The sequences from the flip-flops 11-14 are fed to the indicator 15, the count of which is proportional to the average arithmetic value of the load of these sequences. The phase meter reading is equal to half the sum of the accounts of two full-wave phase meters, in which the zero line is mixed by 30 for one of them and - 30 for the other. Phase meter error caused by pure harmonics in. the composition of the input sipnals, is determined by the relation G1 K s-i-n V cosf Cos 2 cl. where.i is the harmonic number; the ratio of the amplitude of the tl harmonic to the amplitude of the first harmonic, H — phase of the higher harmonic at the moment the first harmonic passes through zero from the minus to the plus oL — zero-line mixing in angular units, and is close to the error of the double phase-phase meter with the immiscible zero line. The error of the phase meter, caused by the third harmonic, is determined by the same ratio and is close to the error that can be attributed to two phase wave phasemeters by even harmonics with an unbiased zero line. Thus, this phase meter reduces, by comparing with the full wavelength; second, the error caused by the third harmonic in the input signals, with approximately the same errors in the phasemeters of both types caused by the even harmonics in the input signals. The invention includes a phase meter containing two canapes, the first and second discriminators of levels in each of the channels, the inputs of which are connected to the inputs of the first and second triggers common to both channels, and the outputs - with an indi-indicator; In order to reduce errors caused by odd harmonics of the input signals, an amplifier with automatic gain control is introduced into it, the third and fourth triggers are common to both channels, and the amplifier with automatic gain control of each channel is connected to moves of the first, second, third and fourth discriminators of their own channel levels, fixing respectively the signal passage moments in each channel through the levels corresponding to the phase angles of the input harmonic signal 30, 150 ,: 210 and 330 °, the outputs of the third and fourth discriminators of each channel's amp level connected to the inputs of the third and fourth triggers, and the outputs of the latter - with the indicator. Sources of information received during examination: 1. P. Smirnov. Digital phase meters. L., Energie, 1974, p. . 2.Vishenchuk I.M., Kotiuk A.F., Mizyuk L., Y. Electromechanical and electronic phase meters, Gosenergoizdat, ML., 1962, p. 168-177. Htf- a - 0-.