SU1352399A1 - Device for certifying phase meters according to phase-amplitude error - Google Patents

Abstract

The invention relates to a technique for phase measurements and can be used to determine the phase-amplitude error. The aim of the invention is to increase the accuracy of the certification of phase meters with phase-amplitude error with an increase in the frequency range. To achieve this goal, the device additionally introduces a frequency shift generator 13, a voltage meter 14, a computing unit 15. In addition, the device contains an input signal source 1, a rotatable phase meter 2, ferrite valves 3 and 4, a level 5 regulator, an adder b , the source 7 of the reference signal, - ferrite valve 8, block 9 phase. an auto-tuning frequency, consisting of a mixer 10, a phase detector 11, and a low-frequency filter 12. 1 hp f-ly, 1 ill. with S oo ego so se se so

Description

The invention relates to a technique for phase measurements and can be used to determine the phase-cell error of phase meters.

The purpose of the invention is to improve the accuracy of the certification of the phasemeter being monitored by phase-amplitude error and the expansion of the frequency range.

The drawing shows a block diagram of the device

The device contains the input signal source I, connected to the first (reference) input of the phase meter 2 being turned, and through the ferrite valves 3 and 4 and the level regulator 5 to the first input of the adder 6 connected at the output to the second (measuring) input of the phase meter 2, the source 7 of the reference signal connected at the output through the ferrite valve 8 to the second input of the adder 6, the phase locked loop system 9, consisting of the mixer 10, the first input of which is connected to the input source 1, the second input to the source 7 of the reference signal, and you stroke through the 1G phase detector and low-frequency filter — with the control input of the reference signal source 7, frequency shift generator 13, connected by the output to the second input of phase detector II, voltage meter 14 connected to the output of the adder 6, computing unit 15, connected with the output of the first phase meter 2,

The device works as follows.

The source signal 1 of the input signal UI frequency is fed to the first (reference) input of the phase meter 2 being turned, and through the ferrite valves 3 and 4, which play the role of decoupling elements, and level 5 regulator - to the first input of the adder 6. To the second input of the adder 6 through ferrite valve 8 receives the signal of the source 7 of the reference signal with the frequency u) + + SI (or Cho - L). And the Ls, and as the decoupling devices, the attenuating attenuators can also be used.

In adder 6, the sum of two signals occurs, and the amplitude of the resulting signal is determined by the expression

and,. i + 2ABCOS (Lf + Fo),

(ABOUT

352399

where a

ten

the amplitude of the signal frequency W; B - frequency signal amplitude

w + n;

Fo initial phase shift; - phase shift arising due to the presence of the frequency difference 57 between the signals. After equalizing the amplitudes of the signals in the adder using a voltage meter connected to the output of the adder, the expression (1) takes the form

15

and.

 V2 A - Vl + cos (q + f). (2)

The signal amplitude is counted at the moment of time, conventionally taken as zero, when d + Ф О, t О, At the same time,. Given the restrictions imposed by the formula (2) receive

25

and Y2 -A,

/ l + cosv -fZ -AO Vl + cos $ Jt.

(3)

A samp at the required time points t-, obtain the required calculated change in the signal level in the reference channel relative to the moment.

The change in the signal level is determined by the expression

4A lOlg

l + cos t

db

So, for example, at Sit, at 2 (tr

(four)

/;

LA -3 dB; with flt, j -,, 687dB.

The moments of reference t., At which the attenuation is equal to the desired value of the LA), is determined from the expression

t. rarccos (2

 l

and A / 10 -10 -1).

(five)

The magnitude of the phase-impulse error Q, at the moments of reference t, is determined from the expression

Q; L1.

1 1 and

- “ti. 2

(6)

where j (/. are the measurements of the value of the phase shift at the instant of reference t -.

The reduction of the effect of random factors is achieved by introducing multiple Q samples. and static processing of results.

With the help of a phase-locked loop system, the low-frequency de-coupling of the input source relative to the reference source is precisely set.

T is set by counting the number of read pulses from the phase meter being turned. In this case, it is required that the reading be carried out at fixed times, and the read pulse itself is stabilized by a high-frequency, for example, quartz oscillator.

At the moment of the maximum value of the signal at the second measuring input of the phase meter being calibrated, its readings have zero values and the read pulse is perceived by the computer as the beginning of the interval t. At that, the computer reads the if values (/ o D) the computer counts the number of read pulses

  3t

(7)

where ate is the time interval between reading pulses. Upon receipt of the nth read pulse to the computing unit

it reads the phase i /. according to a calibrated phase meter and the calculation of the measured phase shift value 4 i / jn, moreover

f, -n

41. in

- „

In an analogous manner, the setting of the t-can also be carried out for phase meters with the reading of information on an external trigger by programming the time delay directly in the computing unit.

ten

15

20

25

thirty

35

 .

40

45

Claims (1)

Invention Formula 1, Phase-Phase Phase Gauge Certification Device, containing an input signal source connected to the first terminal for connecting a rotating phase meter and through a series-connected first ferrite valve, level regulator, and the second ferrite valve to the first input of the adder, which is connected to the second terminal for connection of a phase meter being turned on, the third ferrite valve connected to the second input of the adder, the source of the reference signal, characterized in that, in order to increase the at estatsii and expanding the frequency range, a voltage meter connected to the output of the adder, a computing unit connected to the output bus of a rotating phase meter, a frequency shift generator connected through a frequency control unit from the generator to the input of the reference signal whose output is connected to the second input block phase-locked loop, the third input of which is connected to the output of the input source, signal, 2, The device according to claim 1, 1, and tl, which is that the generator frequency control unit consists of a mixer, the output of which is connected to the output of the phase locked loop through the series-connected phase detector and low-pass filter; respectively, connected to the second input of the phase detector and to the first input of the mixer, the second input of which is the third input of the frequency auto-tuning unit.