SU1190291A1 - Apparatus for measuring angle of phase shift between two modulated harmonic signals - Google Patents

Abstract

A DEVICE FOR MEASURING THE SHIFT ANGLE OF THE PHASES BETWEEN TWO MODULATED HARMONIC SIGNALS, containing a reference frequency generator connected to one of the electronic key inputs via a frequency multiplier, a recorder whose input is connected to the electronic key output and connected to the electronic key two channels connected to an electronic key with a frequency multiplier, a recorder whose input is connected to the output of the electronic key and two channels connected to the electronic key and connected to an electronic key, a recorder whose input is connected to the output of the electronic key and connected to the electronic key two channels connected to an electronic key with a frequency multiplier, a recorder whose input is connected to the output of the electronic key, and two channels connected to the electronic key connected to an electronic key, a recorder whose input is connected to the output of the electronic key and connected to an electronic key which includes a level lock, a block for selecting the moments of signal transition through the maximum value, and a shock excitation generator. the input of which is connected to one of the inputs of the block for selecting the moments of signal transition through the maximum value, characterized in that, in order to increase, the accuracy. measurement, each channel is equipped with a modulation depth amplifier, whose input is combined with one of the device's inputs, and a digital filter, which is a binary counter, two multi-input elements And a d-shaping device, and the output of the modulation depth amplifier is connected to the input of the level clamp whose output is connected to the input of a binary counter and one of the inputs of both elements AND, and each of the remaining inputs of the mentioned elements AND is connected to the output of the corresponding bit of a binary counter, and the output of each of these ementov and coupled to the input of one of the generators, each output of which is connected to the corresponding input block release signal transition moments through the maximum value and the shock generator excitation.

Description

The invention relates to accurate phase measurements in the range of low and infra-low frequencies. The aim of the invention is to improve the measurement accuracy due to the introduction of a most sophisticated digital filter to allow the signal demodulation to be eliminated. The drawing shows the block diagram of the proposed device. The device contains a generator 1 reference frequency, a multiplier 2 frequencies, an electronic switch 3 and the recorder 4, the Start 5 and Reset 6 buttons and two channels, each of which is equipped with an amplifier 7.8 modulation depth with a lock of 9.10 levels, a digital filter, Sushi from a binary counter 11,12, two multi-input elements And 13,14 and 15, 16 and two formers 17,18 and 19,20, a generator 21,22 shock excitation and blocks 23,24 extracting the moments of signal transition through the maximum value. The reference frequency generator 1 is connected to one of the inputs of the electronic key 3 via a frequency multiplier 2, the input of the recorder 4 is connected to the output of the electronic key 3. There are two channels connected to the electronic key 3, each of which includes a latch 9.10, block 23,24 allocating the moments of the transition of signals through the maximum value and the generator 21,22 of shock excitation, the output of which is connected to one of the inputs of the blocks separating the moments of the transition of the signal through the maximum value. Each channel is equipped with an amplifier 7.8 modulation depths, the input of which is combined with one of the device's inputs, and a digital filter, which is a binary counter 11, 12, two multi-input elements 13,14, and two formers 15, 16, and 7.8 modulation depths are associated with an input of a latch 9.10 of level n, the output of which is connected to the input of a binary counter 11.12 and one of the weododes of both elements R 13.14 and 15, 16, and each of the remaining inputs of elements And 13 , 14 and 15,16 are connected to the output of the corresponding bit of the binary counter 11,12, while the outputs Each of the elements And 13,14. and 15,16 are connected to the input of one of the formers 17,18 and 19,20, the output of each of which is connected to the corresponding input of the block 23,24 separating the signal transition points through the maximum generator value 21,22 shock excitation. The device operates as follows. Amplitude-modulated oscillations are fed to the inputs of amplifiers 7 and 8 of the modulation depth, in each of which, along with the amplification signal, the modulation depth increases to values close to 1. Then the signal is limited by voltage clamps 9 and 10 levels (made, for example, in the form of level limiters followed by a rectangular pulse shaper), the level of the limitation being chosen from the condition (1 -m): where m is the modulation coefficient; liftf- amplitude. As a result of the limitation, a periodic sequence of half-waves of the carrier frequency is formed, the amplitude of which varies according to the law of the AM-signal envelope, following the frequency of the modulating C1 | drive. With the help of shapers, which are part of a latch, the limited signal is converted into a sequence of packets of rectangular pulses, which follow a modulating frequency, which are fed to the digital filter, -. each of which is a binary counter with a set, coincidence circuits - (the volume of the counter is chosen from the ratio between the carrier and the modulating frequency). Digital filters highlight the first and last moments of an AM signal passing through a fixed voltage level, i.e. the front of the 1st and the last cut of the pulses of each packet, along which the time interval is formed, the middle of which corresponds to the moment of passage of the maximum point of the AM signal envelope. Block 23 and 24 of the selection of the maximum of the AM signal envelope, gated by the pulses of the shock excitation generators 21 and 22, form short pulses, the instants of which correspond to the maximum of the envelope of the AM signal in each channel. These pulses form times31

Noah interval proportional to the angle of the phase shift between the envelopes.

The electronic key 3 and the reference generator 1 ensure the filling of the time interval received by the pulses of the reference frequency. Recorder 4 is a digital computing device consisting of standard nodes and performing arithmetic operations, the result of the calculation should be displayed on a digital scoreboard. .

The phase angle is determined to measure the instantaneous value of the angle as the product of the number of pulses Njf proportional to the angle of shift

902914

phases, on the ratio of the input frequency

signals {. "and reference frequency

Quartz oscillator tf multiplied

factor of 36 (translation to

5 degree angle measure) :. Vsr J ..

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tr

. Thus, the advantage of the proposed device is to ensure that the phase angle between the envelopes of the amplitude-modulated oscillations is directly and directly distant, which allows the measurement accuracy to be raised to the level of accuracy achieved for sinusoidal signals.

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Claims (1)

DEVICE FOR MEASURING ANGLE OF PHASE SHIFT BETWEEN TWO MODULATED HARMONIC SIGNALS, containing a reference frequency generator connected to one of the electronic key inputs via a frequency multiplier, a recorder whose input is connected to the electronic key output, and two channels connected to the electronic key, each of which includes two channels a level lock, a block for allocating moments of the transition of signals through the maximum value, and a shock excitation generator, the input of which is connected to one of the inputs of the moment allocation block ntov transition signal through a maximum value, characterized in that, in order to improve, accuracy. measurement, each channel is equipped with a modulation depth amplifier, the input of which is combined with one of the device inputs, and a digital filter, which is a binary counter, two multi-input elements And and two shapers, moreover, the output of the modulation depth amplifier is connected to the input of the level lock, the output of which is connected - with the input of the binary counter and one of the inputs of both AND elements, and each of the other inputs of the mentioned AND elements is connected to the output of the corresponding bit of the binary counter, while the output of each of the elements And it is connected with the input of one of the formers, the output of each of which is connected to the corresponding input of the unit for extracting the moments of the signal transition through the maximum value of the th generator of shock excitation. .SU 1190291 1 1190291 2