SU1377765A1 - Method of determining phase shift - Google Patents

Abstract

The invention can be used to measure the phase shift of signals comprising a constant component. The purpose of the invention is to reduce the time and increase the accuracy of measurement. A device that implements the method contains a generator 1 of the reference voltage, multipliers 2. .. 7, quadrants 8 ... 10, integrators 11 ... 16, elements 17 and 18 of the voltage, converter 19 ratios, block 20 of the arctangent calculation, indicator 21 and a control unit 22. The device allows wire. the following operations. The sine and cosine component (CS) of the reference signal is squared and integrated. The CS and the measured signal (IC) are also integrated. Then, the result of integrating the multiplied QS and ICs is multiplied with the result of integrating the square of the sine component (CC) of the reference signal. The results of the integration of the measured signal, the CS, and the square of the SS are multiplied and the last result of the multiplication is subtracted from the penultimate result of the multiplication. The result of the integration of the multiplied ICs and the CCs are multiplied with the result of the integration of the CS square. After that, the result of the integration of the QS is squared and multiplied with the result of the integration of the multiplied ICs and CCs. From the result of the penultimate multiplication, I subtract the result of the last multiplication and calculate the measurement result from the results of the subtraction data. 4 il. t l ijTlо оо чЗ О) SD FIG. one

Description

The invention relates to electro-radio measurements and can be used to measure the phase shift of signals that include a constant component in a short measurement time, including a measurement time that is shorter than the signal period, with increased accuracy and noise immunity. .

The purpose of the invention is to reduce the time and increase the accuracy of measurement of phase shifts of signals.

Figure 1 shows a block diagram of a device that implements the proposed project; Figures 2 and 3 are a diagram of a control unit with time diagrams; in fig. 4 is a block diagram of a reference voltage generator.

The device contains (Fig. 1) a generator I of the reference voltage, multipliers 2-7, quadrants 8-10, integrators 11-16, elements 17 and 18 of the subtraction, a ratio converter 19, an arctangent calculation unit 20, the indicator 21, the control unit 22 wherein the voltage generator 1, the outputs are connected to multipliers 2 and 3 and quadrants 8 and 9, the second inputs of multipliers 2 and 3 and the integrator input 11 to the input signal bus of the measured signal, alternators 2 and 3, quadrants 8 and 9 and the cosine output of the generator 1 - the reference voltage is connected to the inputs according to -retarded integrators 12-16, the outputs of integrators 11, 14 and 16 are connected to the inputs of the multiplier 4, the integrator output; 16 is also connected to the input of a quad 10, the output of which is connected to the input of multiplier 5, to the second input of which is connected, the output of integrator 12, which is also connected to the input of multiplier 6, the second input of which is connected to the output of integrator 15, the outputs of integrators 13 c 14 connected to the inputs of multiplier 7, outputs of multipliers 4 and 7 are connected to inputs of subtraction element 17, outputs of multipliers 5 and 6 are connected to inputs of subtraction element 18, outputs of elements 17 and 18 of subtraction are connected to a ratio converter 19, the output of which connected to the input of the arctangent calculator 20, the output connected to the indicator 21, the first output connected to the control

the inputs of the generator I of the reference voltage and the integrators 11–16, the second output is connected to the control inputs of the integrators P-16 and the indicator 21.

The control unit (Fig. 2) contains the start pulse pulse generator 23, the timing of the driver element 24 and the pulse former 25, which are sequentially interconnected. The outputs of the control unit are a and 5.

The reference voltage generator (Fig. 4) contains a clock generator (TG) 26, the input of which is connected to the output of the control unit, two storage units 27 and 28, whose inputs are connected to the output of TG 26, and two digital-analogue converters 29 and 30 The inputs of which are connected to the outputs of the storage units 27 and 28, and the outputs are the outputs of the sine and cosine signals of the reference voltage generator 1.

The essence of the proposed method consists in the following.

The phase shift is determined by the expression

LAT - about OAR,

ugm ° s te in which

1H

 about / i s (t) (0 dt,

u. -g „11

(s) (t) dt;

one

-You g

TM /

0 t;

J u u

-Tm / - "/ 5

A 1 S, (t.) Dt;

-v;

T „/ 5

B, S Soc (t) t;

. -T "(7

TV, /.

Bj f g s; jt) jt,

 i-tts / a

where S (t) is the measured signal; S Q5 (t); S () is the sine and cosine components of the reference signal.

The method is implemented as follows.

The moment of the measurement start is formed by the shaper 23 of the start pulse of the control unit 22 operating in the manual or automatic modes Time the driver element 24 of the control unit 22 is formed a pulse equal in duration to the integration time Ti (FIG. 3), which is fed to the generator 1 through the slit a for the input of the clock generator 26 and the integrators 11-16. During the integration time, the reference voltage generator 1 generates the sine and cosine components of the reference signal, which are fed to multipliers 2 and 3, quadrant 9 and integrator 16. Multiplied with the measured signal, the cosine component of the reference signal is squared by the cosine component of the reference signal and the measured signal is integrated over time T. After the end of the integration, the results of the integration are memorized for a time (FIG. 3) equal to the duration of the pulse from the output of the driver 25 pulse ov, coming on tires e S on all integrators and the indicator. The signals from the outputs of the integrators, which are constant in time during pulse pulse 5, are fed to the corresponding multipliers 4-7 and quadrant 10. At the output of multiplier 4, a signal is generated that is proportional to the multiplied values o (((j A, jB, by the output of the multiplier 6 is a signal proportional to the multiplied values of o In the code multiply l 7 - a signal proportional to the multiplied values m / s, at the output of the quad, 10 is a signal proportional to the value of b, the output of the multiplier 5 is a signal proportional to the multiplier th values of B m, where o, d

four

Bi,

Bj are labeled in accordance with 2-7. The signals from the outputs of multipliers 4-7 are fed to the subtraction elements, which are fed to the ratio converter, the output of which is a signal proportional to the value (/ lA - o AjB) / (d (B - oSV). This signal goes to the calculation unit arctangent, which calculates the phase shift by arctangent from the value of the signal at its input. The result of the calculation goes to indicator 21, which stores it during the pulse on the bus and displays it

- ten

15

20

25

thirty

35

40

45

50

55

until the end of the next measurement.

Using the proposed method makes it possible to reduce the measurement error. This is especially important when measuring the phase shift of signals at infra-low frequencies with a measurement time shorter than the signal period. For small times, shorter signal period, the error can reach 20 ° and more, i.e. measurement actually becomes impossible. To perform a measurement with acceptable accuracy, the measurement time must be increased to a value that is a multiple of the period (half-period) of the signal. Thus, it is possible to significantly reduce the measurement time. For example, at a frequency of 0.001 Hz, the minimum measurement time of the prototype is 500 seconds, and when using the proposed method, the measurement time can be reduced by one to two orders of magnitude.

Claims (1)

Invention Formula The method of determining the phase shift, based on multiplying the measured signal by the sine and cosine components of the reference signal, integrating the multiplication results and calculating the result of the measurement by the arc tangent of the ratio, characterized in that, in order to reduce the time and increase the accuracy of measurement, the sine and cosine components the reference signal is squared and integrated, the cosine component of the reference signal is integrated, the measured signal is integrated, then the result of the integration of the variable The measured signal and the cosine component of the reference signal are multiplied with the integration result of the square of the sine component of the reference signal, the integration results of the measured signal, the cosine component of the reference signal and the squared sine component of the reference signal are multiplied and the last result of the multiplication is subtracted and the last result of the multiplication is multiplied the result of integrating the multiplied measured signal and the sine component of the reference signal is multiplied with the result and tegrnrovani square cosine component of the reference signal, the result of integrating said cosine component of the reference signal is erected into squared and multiplied with the result of integrating said multiplied the measured 13777656 the signal and the sine component of the reference signal, the result of the last multiplication is subtracted from the result of the penultimate multiplication, and the measurement result is calculated from the results of the subtraction data. 23 Zif Phie, 3 but 25 FIG. 2 Ty CDi / e.