SU1707567A1 - Method for measuring signal phase difference - Google Patents

Abstract

The invention relates to electrical measuring equipment and can be used in electrical and radio engineering installations for various purposes in measuring phase shifts of signals. The aim of the invention is to expand the range of measurable values of the phase difference of the signals. The invention is based on the primary periodic switching of the studied signals at the inputs, parallel channels, amplification of the amplifier and frequency conversion when adjusting the frequency of heterodyne oscillations and subsequent secondary switching of the intermediate frequency signals so that in one of the equal switching cycles the phase difference between the intermediate frequency signals at the outputs is measured the first and second channels, and the other at the inputs of the second and first channels. Then the amplitude of the signal is proportional to one of the cycles. (ft + & q), in the other (A1 - & tf), where is the measured phase difference between the studied signals; & U) - the difference of phase ramps in the channels, integrate. A feature of the invention is that the secondary switching of the signals is carried out before, and the integration of the signal after measuring the phase difference of the signals, the intermediate frequency. 2 Il. a $ /)

Description

The invention relates to electrical measuring equipment and can be used in electrical and radio engineering installations for various purposes when measuring phase; shifts.

The aim of the invention is to expand the range of measured values of the difference fsz sigalo h.

FIG. 1; iii; iiv2, T, u: na structures :: .-; -: the electrical circuit of the device measuring the phase difference of signals, implementing the method of measuring the phase difference of the signals in FIG. 2 - temporary

diagrams explaining the operation of the device measuring the phase difference of signals

The device for measuring the phase difference of the signals includes the switch 1 of the two signals under study, the first and second parallel amplification and mixing channels 2 and 3, auxiliary channel 4, the local oscillator 5, the automatic frequency control unit 6, the synchronizer 7, to: tension 8 sngn M: o1 : e: -:. 1-t1:; r-D-frequencies, and - c: et r 9 a nnchch.-) p. ten.

A parallel channel contains amplitudes of the studied signals, superheterodyne mixers

ABOUT

J

ate &

type, amplifiers amplitude signals of intermediate frequency.

Amplification and mixing channels 2 and 3 together with the local oscillator 5 form the first (2 and 5) and second (3 and 5) channels of the two-channel amplifying conversion path, respectively.

Amplification and mixing channel And together with the local oscillator 5 forms an auxiliary amplifying-converting path (A and 5). The auxiliary amplifier-converting path (A and 5) together with an automatic frequency control unit 6 forms the automatic frequency control system (4, c and 6).

In the channels of the two-channel.):. Of the and the auxiliary amplifying-conversion paths carry out single or multiple both amplification and frequency conversion.

The first and second outputs of the switch 1 of the signals under study are connected to the signal inputs of the amplifier-mixing channels 2 and 3, respectively. The outputs of the latter are connected to the first and second inputs of the switch 8 of the signals of the intermediate frequency, respectively, the outputs of which are connected to the first and second inputs of the phase meter 9, respectively. Phase meter output 9-pinen with integrator Vg.odome 10.

The first, second, and third outputs of the local oscillator 5 are connected to the heterodyne inputs and the mixing / mixing channels 2, 3, and 4, respectively, are amplified. The signal input of the auxiliary channel A is connected to the second input of the switch 1 of the signals under study. The output of the amplifier-mixing channel And is connected to the input of the block 6 automatic frequency control. The output of the automatic frequency control unit 6 is connected to the control input of the local oscillator 5.

The first and second outputs of the synchronizer 7 are connected to the control inputs of the switch 1 of the signals under study and the switch 8 of the signals of the intermediate frequency.

The method of measuring the phase difference is realized.

On the first and second inputs of the switch 1 serves the first and second signals under investigation, respectively. Issle

five

0

the signal from the second input of the switch 1 is continuously fed to the signal input of the auxiliary channel A. The signal from the output of the automatic frequency control system (A, 5 and 6) is fed to the control input of the local oscillator 5. The system automatically adjusts the frequency (A, 5 and 6 ) control the local oscillator 5. so that when the frequency of the signal under study at the second input of switch 1 changes, the frequency of the intermediate frequency signal at the outputs of the output of the mixing and mixing channels 2, 3 and A is kept unchanged. The switch 1 of the signals under study and the switch 8 of the signals of the intermediate frequency work synchronously, in two cycles, while

Ъ А TKOM

not

Thr

five

0

five

0

five

where Tcom is the switching period,

Even Nothing Duration of even and even measures, respectively.

Odd clock pulses are sent to odd clock cycles from synchronizer 7 to the control input of switch 1, the signal being investigated from the first input of switch 1 is fed to its first output and then to the signal input of the mixing and mixing channel 2, and the signal from the second input of switch 1 is fed to its second output and further to the signal input of the amplification-mixing channel 3.

Even clock pulses are sent to clear control clock from synchronizer 7 to the control input of switch 1, the signal being investigated from the first input of switch 1 is fed to its second output and then to the signal input of the mixing and mixing channel 3, and the signal being studied from the second input of switch 1 is fed on its first output and further on to the signal input of the amplifier-mixing channel 2. The first and second signals under study at the input of switch 1 have the phases φ {and Pg, respectively. .

Measure the phase difference of the studied signals.

5 C (- -)

0

or

dr 02 -Р, - (, 02)

depending on which of the studied signals is taken as the reference.

The difference of phase ramps & tj in the first channel (2 and 5) of the amplifier-converter path relative to the second channel (3 and 5) is due to the fact that the values of the own phase ramps in each of the channels are not the same and, moreover, are not constant in time.

The phase difference of the signals of the intermediate frequency at the input of the switch 8 is equal to

AV-VI-,

where (jJj is the phase of the intermediate frequency signal at the output of the first channel (2 and 5) Jv

(l - phase of the intermediate frequency signal at the output of the second channel (3 and 5).

If the first signal under investigation is taken as the reference signal, i.e.

 -R,,

then the magnitude of the phase difference of the signals of the intermediate frequency at the input of the switch 8 n odd cycles

  P "+ - + LC) -Fg + LC,

where fjnech is the phase of the intermediate frequency signal at the output of the first channel (2 and 5) at odd so you have the laza signal. the intermediate frequency at the output of the second channel (3 and 5) at odd beats,

and the magnitude of the phase difference of the signals of the intermediate frequency at the input of the switch 8 in even cycles

Lfchet "even (+ LF-R, -Af + ACf,

where (fJj c is the phase of the intermediate frequency signal at the output of the first channel (2 and 5) in even beats}

ZMCT Phase signal intermediate-. . frequency at the output of the second channel (3 and 5) even. th bars

Odd clock cycles from synchronizer 7 to the control input of switch 8 receive odd clock pulses, while the signal is passed through.

2 sword

0

five

0

five

0

five

0

five

0

the frequency from the output of the first channel (2 and 5) is fed to the first output of the switch 8 and then to the first input of the phase meter 9t and the intermediate frequency signal from the output of the second channel (3 and 5) is fed to the second output of the switch 8 and then to the second input of the phase meter 9 .

In the even clock cycles from the synchronizer 7, even pulses are received at the control input of the switch 8, the intermediate frequency signal from the output of the first channel (2 and 5) is fed to the second output of the switch 8 and then to the second input of the phase meter 9, and the intermediate frequency signal from the output of the second channel (3 and 5) is fed to the first output of the switch 8 and further to the first input of the Gasometer 9.

The magnitude of the phase difference of the signals of the intermediate frequency at the input of the phase meter 9 in odd cycles

AUnech in AfivechvL0 + AN, .a value of the phase difference of the signals of the intermediate frequency at the input of the phase meter 9 in even cycles

   , .- (- & 0 + Atf) - A0-A (f ...

The signal at the output of the phase meter 9 or Uq tset- (Fig.2) directly proportional to the phase difference or B odd or even cycles, respectively. The output signal of the phase meter 9 Ua is fed to the input of the integrator 10. The output signal of the phase meter 9 U has a constant component, the amplitude U of which depends on the measured phase difference of the studied signals L F, and the variable component whose amplitude & U depends on the difference phase raids in th channels.

 As a result of integrating the output signal of the phase meter 9 at the output of the integrator 10, a signal U is received (Fig. 2), the amplitude of which corresponds to the amplitude U the constant component of the output signal of the phase meter 9

In this way,

55

 + WJLi 2

() + (..

Consequently, at the output of the integrator 10, a signal is obtained, the amplitude of which corresponds to the measured phase difference of the DF signals under study and does not depend on the magnitude and sign of the difference of the phase shifts in channels.

Claims (1)

Invention Formula The method of measuring the phase difference of signals, which initially periodically commute into even and odd cycles of the same duration over the switching period, the signals under study to the inputs of the first and second parallel channels, the incoming signals channel changes into each clock cycle, the signals in the first and second parallel channels by mixing them with the signal five 0 the local oscillator, whose frequency is related to the frequency of the signal under study, is periodically switched from time to time into even and odd cycles of the same duration during the switching period, so that the polarity of the signal is inverted into even (odd) cycles or remains unchanged into odd (even) cycles, the amplitude of the signal is integrated, and the sought phase difference of the studied signals is determined by the magnitude 1 of the amplitude of the integrated signal, characterized in that, in order to extend the range, the measured values of the phase difference of the signal s, secondary prorod periodic switching signal to m, and the integration of the signal amplitude - after the measuring phase difference between the converted signals. FI2,1