SU531125A1 - Method for measuring delay time - Google Patents

Description

the change in the input to the auxiliary frequency, and the friend is fed in from the line output. The measured offset between these two frequencies is determined by the Delay Burm. Then the frequency of the auxiliary signal is measured in such a way that the value of the frequency I. is preserved, i.e. Pw-w, and the phase shift is measured as described. The sought delay time is determined by dividing into four sums of measurement results in two cycles.

The delay time is determined from the expression

ft

roi -t-rw

H

sg-gsh

g

where oi (JU, and ft are, respectively, the input and auxiliary signals and the difference frequency signal, respectively; TOU TUJ troiS. is the delay time of the signals of the line under investigation, respectively, at the frequencies W; I, L;

To reduce methodical error

TCJU -HL ft

, -t „

make a second measurement.

If in the first measurement the difference frequency was determined from condition 51, then in the second measurement, equality I is achieved. - i - J The results of both measurements are summed up and divided by four. The delay time is determined from the expression

2TSh -f-tCU -vrtc aCtUUj.)

34.SH

Where TSH.- time delay signal with a frequency of 2. in the line under study.

Methodical error is

attU -tlUj-tCJU ftCClD -ttJUj)

At

4-u;

Claims (2)

Invention Formula The method of measuring the delay time of the signal, by which the phase shift of two signals is measured, the first of which is fed to the line input, and the second is removed from the line input, characterized in that, in order to measure the delay time of the communication line with the input and output spaced in space , an auxiliary signal is supplied to the line output, the frequency of which differs from the frequency of the input signal by a fixed value; the input and auxiliary signals are mixed and the difference frequency signals are extracted at both ends of the line, with the selected At the line output, the difference frequency signal is directed to the line input and the phase shift between the difference frequency signals is measured, one of which is received at the line input, and the other is transmitted to the input from the line output, and the measurement is taken in two cycles, and the second cycle, the frequency of one of the signals is shifted by twice the value of the fixed difference frequency so that the value of the difference frequency remains unchanged, and the desired result measurements are found by dividing by four sums of measurements in two ticks. Sources of information taken into account in the examination: 1. USSR author's certificate No. 163221, C 04 G 10 / O6, 09/05/1964. 2. USSR Author's Certificate No. 369543, C 04 F 10/06, 15.Ab.1973.