SU1278733A1 - Digital phasemeter - Google Patents

Abstract

The invention can be used in measuring the instantaneous value of the phase angle of two electrical signals. The aim of the invention is to increase the speed and accuracy of measurements. To achieve this goal, an auxiliary counter 4 and a controlled frequency divider 6 are introduced into the digital phase meter. The digital phase meter also contains drivers 1 and 2, a counter of 3 pulses, a divider of frequency 5, electronic switches 7 and 8, and a generator of 9 pulses. This digital phase meter reduces the measurement time to two periods of the input signal. 1 il. (f) Yu Nj 00 with

Description

The invention relates to a measurement technique and can be used when measuring the instantaneous value of the phase angle of two electrical signals. The purpose of the invention is to increase the speed and accuracy of measurements by reducing the measurement time to two periods of the input signal and using a stable pulse generator. The drawing shows the structures on the phase meter circuit. The phase meter contains drivers 1 and 2, a pulse counter 3, an auxiliary pulse counter 4, a frequency divider 5, a controlled frequency divider 6, electronic switches 7 and 8, and a pulse generator 9. The reference signal bus U is connected in series through the first driver 1, the first electronic switch 7, the controlled frequency divider 6 connected to the input of the counter of 3 pulses. The pulse generator 9 is connected to the second input of the first key .7 and through a series-connected frequency divider 5, the second electronic key 8, an auxiliary counter of 4 pulses to the control inputs of the controlled frequency divider 6. The input of the measured signal U through the second driver 2 is connected to the first input of the second electronic switch 8 and the third input of the first electronic switch 7. The drivers 1 and 2 are designed to select time intervals corresponding to the transition times of the studied V and reference U (j signals through zero values) the counter 4 is used to set, according to the measured period of the signal under study, the magnitude of the division factor K il of the controlled frequency divider 6. The latter ensures the formation of The pulses, the frequency of which is fn and Czo, are times less than the frequency f of the pulse generator 9. A pulse counter 3 is used to form the result of measuring the phase shift in digital form. The electronic switches 8 and 7 control the delivery of counting pulses to the auxiliary account, respectively. 4 pulses and a controlled frequency divider 6. In the initial state, before starting the measurement, the keys 7 and 8 are closed, the counters 3 and 4 pulses in the controlled frequency divider 6 are set to the zero state (the installation circuit is in the idle state on the black hedgehog not shown). Phase meter works as follows. Let UQ be behind Uj, by an angle q. The phase shift measurement is performed in two clocks. In the first cycle, the period of the signal under investigation is measured by filling the counter of 4 pulses with pulses from the output of the frequency divider 5, which has a constant division factor Ka. In this case, shaper 2 generates a positive rectangular pulse, the duration of which corresponds to the duration of the positive half-wave of the signal under study. This pulse opens the key 8, and in the counter of 4 pulses the number N is written, equal to P S-- --T K T T J jr where K, is the ratio of f (- / 2fa. The code of the number N from the bit outputs of the counter 4 The pulses are fed to the control inputs of the division of the controlled frequency divider 6. As a result, in the first clock cycle, the controlled frequency divider 5 is being prepared to measure the phase shift. In the second cycle, the square pulses from the outputs of the formers 1 and 2 are fed to the control inputs electronic key 7 and open this class At the output of the controlled frequency divider 6, pulses are formed, the frequency of which is directly proportional to the frequency of the input pulses f |. and is inversely proportional to the division factor of the controlled frequency divider 6 About KUO - KjT. As a result of this, the time in the resulting counter of 3 pulses is written down the number N., equal to

f fr ffZKa. -to

- -.- about - UZ

to ,, t

f.-T

 to - | -. Kc | ..

Claims (1)

The number of pulses Ng is directly proportional to the phase shift. Invention Formula Digital phase meter containing a pulse counter, the first driver, the input of which is connected to the reference signal bus, and the output to the first input of the first electronic key, the second input of which is connected to the input of the frequency divider and the output of the pulse generator, the second driver, whose input is connected to the tire of the studied signal. and the output with the third input of the first electronic key and the first input of the second electronic key, characterized in that increase the speed and accuracy of measurements, an auxiliary counter and a controlled frequency divider are added to it, the output of which is connected to the counting input of the pulse counter, the counting input - with the output of the first electronic key, and the control inputs of the division factor - to the bit outputs of the auxiliary counter, counting input KOToptSro is connected to the output of the second electronic key, the second input of which is connected to the input of the frequency divider.