SU467293A1 - Digital device for measuring the phase difference of two harmonic signals - Google Patents

Description

of abilities. The generated reset pulses through the delay lines 12 and 13 arrive at the installation input of the counters 14 and 15 to the initial state. From the output of the counters 14 of the upper and 15 lower channels once per period of the total sequence, the pulse arrives at the “single and” zero inputs of the output trigger 17. Since there is a rio phase shift between the signals of the upper and lower channels; then between the pulses of setting the trigger to the state "1 and" O there is a time shift proportional to the phase difference, and consequently, at the output of the trigger 17, a pulse is formed whose duration is proportional to this difference. The voltage from the unit output of the trigger 17 is applied to the control input of the AND circuit, the second input of which is fed to the counting pulses from the output of the source of counting pulses 16. At the times determined by the resolution potential from the trigger output 17, the counting pulses pass through the circuit “And on the main counter 18. The number of pulses recorded in the counter is proportional to the phase shift between the measured signals. The indication of the number of pulses recorded in the counter 18 is carried out by a digital readout device.

Allocation of the period of the formed cumulative sequence is possible due to the fact that once per period in the cumulative sequence a positive impulse appears, the duration of which is maximum and differs sharply from the others. The duration of the maximum pulse of the total sequence is equal to the duration of the reference frequency period (local oscillator). Counters 14 and 15 just provide an indication of this maximum pulse. When changing the frequency of the signals under study, the frequency of the local oscillator needs to be changed so that the period of the total sequence remains constant. Capacities of the counters 14 and 15 are selected for a given frequency of the counting pulses, based on the period of the reference frequency.

When the device operates in a certain frequency range, the following condition must be fulfilled: the maximum duration pulse of the total sequence at the maximum

the frequency of the local oscillator must be greater than the duration of any non-maximal pulse of the total sequence at the lowest frequency of the local oscillator. V.- pr.ot-ivnom case it is necessary to produce a partition

subbands by changing the capacitance of the counters 14 and 15 for each of the subbands. The accuracy of the measurement of the phase difference in the proposed device increases as a result of the replacement of analog mixers and resonant

FFC discrete adders and counters, as well as eliminating the possibility of additional phase shifts due to the passage of the measured signals through various channels. The phase difference measurement process is simplified, since it is not necessary to equalize the phase shifts in both channels before each measurement.

Subject invention

Digital device for measuring the phase difference of two harmonic signals, containing shapers, adders, circuits, counters, trigger, counting pulse generator and recording device, characterized in that, in order to improve the accuracy and simplify the measurement process, it is equipped with two lines delays, two schemes of formation of pulses of reset,

moreover, the outputs of the adders of both channels are connected to the control inputs of the "And" schemes and through serially connected schemes of the formation of reset pulses and the support line to the inputs of the installation of meters in

the initial state, the second inputs of the "And" circuits are connected respectively to the single and zero inputs of the output trigger, the single output of which is connected through the series-connected circuits "And to the output

counting pulse generator; the main counter is connected to the recording device.

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