SU1350622A1 - Device for meausuring modulus and phase of complex reflection factor of four-terminal network - Google Patents

Abstract

This invention relates to the SV-H radio measuring technique and provides an increase in measurement accuracy in the frequency range. The device contains a signal generator 1, which is investigated by a two-source (id) 2 ,. four-probe sensor (RON) 3 with 4-7 communication probes (ES), switch 8, control unit 9, quadratic detector 10, pe

Description

15

i. Tff

Ijl 20

U

locker 11, memory block 2, D / A converter 13, block 14 multiplying 5 band-pass filter 15, linear amplitude detector / 16 ,, controlled voltage divider 17, module indicator 8, phase meter 19, phase indicator 20, reversible counter 21, comparator torus 22, elements And 23, 26, pulse generator 24 and inverter 25. The signal of the incident wave from generator 1 through the FWD 3 is fed to the ID 2.- The signal sent from the .ID 2 wave interferes

The invention relates to microwave radio technology and can be used in automatic measuring systems and devices, embedded control,.

The purpose of the invention is to improve the accuracy of measurements in the frequency range.

The drawing shows a structural, electrical diagram of the device, dp, measuring the module and the phase of the complex reflection coefficient of the two-pole network.

Device} 1l of measurement of the module and the phase of the complex displacement factor of a two-terminal device contains a signal generator 1, a two-terminal 2 under study, a four-probe sensor 3 with communication probes 4-7, switch 8, control block 9, quadratic detector 10, switch 11, block 12 pag / 1 THD digital analogue converter 13, multiplication unit J4, bandwidth F1-pin 15, linear amplitude detector 16., Controlled voltage divider 17, indicator 18 modl, meter 19 phase, indicator. 20 phase, reversible counter 21, comparator 22, the first element And 23, geoinverter 25 and

nerator 24 pulses second element And 26

A device for measuring the modulus and phase of the complex factor from

5a

and,

K. 005 (-1 K.U, l-.Hrl42 | rlcos (f. X, .1г | Ч2 | г1со8 (, |. -N гГ - 1-21Р1соз. (1 + о

K.iUn

with the incident wave signal. Field distribution analysis is carried out by AP 4-7, thrashed); engraved in different sections of the WVD 3, Switch 8 commutes., AP signals 4-7 to the common channel. In the multiplier 14, the signals are multiplied by the values that correct the measurement errors caused by the non-identical characteristics of the ES and the channels of the switch 8. The correction values are entered in memory block 12 in the calibration cutter. 1 il.

The dvukhpolyusnika razheni works little.

The signal of the incident wave U from the generator 1 through the four-probe sensor 3 is fed to the complex two-terminal 2 with a complex reflection coefficient

G 1P

chd

five

0

50

Where

- modulus of the complex reflection coefficient; tf is the phase of the complex reflection coefficient.

The signal of the wave reflected from the input of the studied two-terminal 2 interferes with the signal of the incident wave and. The field distribution analysis is carried out using four probes 4-7 placed in different sections of the four-probe sensor 3 so that the phase incursions between them are 1T / 4 at the average wavelength of the working range.

The switch 8 on the commands of block 9 periodically switches with a frequency of 52 each of the output signals from the probes 4-7 in a common channel. The quadratic detector 10 detects the output signal of the switch 8. The output signal of the quadratic detector 10 is a periodic function, which on the interval equal to the switching period T 2 ir / f2. Has

- (, with -cpl, with + cf), with T / 2 t 3T / 4; + H), with ST / 4 t T,

3 1350622 de K, K ,, K, K. - transfer coefficients of the four-probe sensor 3, the switch 8 and the quadratic detector 10 for each of the probes 4-7, respectively, at the i- and frequency;

S, y - frequency coefficients;

, 2,3 ... n is the frequency number, where n is the number of frequencies

J. ё

ten

The range of the generator is 15, which is equal to

ra 1. Coefficient o depends on separation

probes 4-7 along the path and defined by the formula

 / l ;,

where asp is the average wavelength of the range; L; - discrete value of the current

wavelength.

The coefficient y depends on the rotation of the probes 4-7.

2

one

 + ln42 | r | C + 2 | rrcos (-c, with

   1 + | G | 2 | G | + 21Г1 cos (- | iL -cpj, with T / 4-t-T / 2;

and „and.

- -(four)

UnUn.l + lnV2 | ri + 2 | rrcos {- - Y- + tf), with T / 2 t-3T / 4;

and „and

l + | rlV2lr | + 2iricos (5 | i +: i: + (f, with.

The band-pass filter 15 extracts the first-: first harmonic from the output signal: Uj of block 14. The voltage Uj from the output

. and, | p, in | i cosVsin (|) + sin; fcos4 p, (5)

Kj and Kg are the transmission coefficients of the bandpass filter 15 at the frequency Q and the linear amplitude detector 16, respectively;

ulrl U4CP-U4. 2

iPl

 ; rSД

 4sr

1- t sin D | J cosVsinM) + sin e cos4 |); (6) -Go

 442

where and, „ZJ- ± lhi ° h: n, g, for example, When changing the frequency in 50%

ip t plyrlzhe band is the maximum value of the error at the output of the linear amplitude calculated by the formula (6) of the tedious detector 16 at the middle edges of the range (at cf and / 2) of the range of the wavelength of the range 6 , 8-16%. ()

622

For a coaxial channel in the 50% frequency band, the coefficient S varies between 1.33 and 0.8, and the coefficient J. of J – J varies between 0.75 and 1.25, i.e. these coefficients have a significant frequency dependence,

In measurement mode, switch 11 switches unit 12 to read mode. In this case, the signal from the first output of block 9 and the signal from the synchronization output of the generator 1 are read to the output of block 12 codes. The digital-to-analog converter 13 converts these codes to signal

0

and,

the switching period T has the form

 and „/ K ,; , at 0 t-T / 4, UO / K ,,; with ,; , at T / 2 t-3T / 4, ° at 3/4-t-T, where UQ is a constant value.

Block 14 multiplies the signal U with the signal and. As a result, the output 25 signal-and block 14 on the interval, equal to the switching period T, has the form

bandpass filter 15 is detected by a linear amplitude detector 16, the output voltage of which is

Р 5+ - total frequency factor 45.

The relative measurement error of the modulus of the complex reflection coefficient in accordance with formula 5 when operating in the range of frequencies is equal to

3506226

the band varies between 2.05 and 2.08, i.e. little dependent on the frequency.

In order to eliminate the component error associated with the coefficient

1- I 2 2 / -h-7 ft-signal and, is fed to a controlled de-sin ji-H-A cosqisin (g) + sin (f g j. Voltage detector 17, coefficient

the transmission of which is calculated by the ncJ formula--i. .

hb5.

From the expression (6) it follows that the measurement error of the modulus of the complex reflection coefficient is determined by the product of two members

R

Greatest contribution to the error

sit sin d- term, since the & varies significantly with frequency tuning. - The contribution of the second term is less, since it is determined by the frequency coefficient, which, in accordance with (2) and (3) in 50%

ten

(7;

sin -7

In this case, the voltage at the output of the controlled separator 17 of voltage 15 has the form

I and EMiHn | p, eosVsin4 |) -bsinVcos (|). (8)

This voltage is applied to the indicator 18, the scale of which is calibrated in the values | Г | . The error due.

2

1- - | eosVsin (|) -fsinVcos (|). (9)

In the 50% band (npaCf / 2), this error at the edges of the range is 2.0-3.3%.

- At the same time, the voltage from the output of the bandpass filter 15 is fed to the input of the meter 19, at the output of which the voltage is

. U: K, Cf, (10)

where Kj is the transfer coefficient of the meter 19.

This voltage is applied to the indicator 20, the scale of which is calibrated in the values of -f

Measurement mode 1-1 is preceded by a calibration mode, in which the two-terminal 2 under study is matched load with the reflection coefficient module (Г | 0. At the same time, the four-probe sensor 3 sets the traveling wave mode and the signal and reproduces its amplitude-frequency characteristic of the four-probe sensor 3, - switch 8 and quadratic detector 10 for each of the probes 4-7

K,; U, with 0 t-cT / 4;

Cg-and „% at TA4 g T / 2;

 . hell, at T / 2-t-3T / 4; .,,

 KH, with 3T / 4-t T.

to -i-. .

hb10

(7;

hb

sin -7

In this case, the voltage at the output of the controlled separator 17 of voltage 15 has the form

20 measurement depends only on the frequency, coefficient and is determined by the formula

five

0

In the calibration mode, the switch 11 switches the block 12 to the Record mode, in which the block 12 writes the output code of the reversible counter 2 into the memory array corresponding to one of the probes 4-7 currently included in time. The digital-analog converter 13 converts the output block code 12 in the signal U..

Further work in the calibration mode, consider the example of the formation of the signal U-j on the time interval 0, corresponding to the inclusion of probe 4 at the i-th frequency of the generator I,

The comparator 22 compares the signal 1/2 with the reference signal Ug. With the fulfillment of the condition U, and „comparator 22

B / o

switches to the unit state and opens the first element AND 23j which transmits pulses from the output of the generator 24 to the subtraction input of the reversible counter 21. With the arrival of each pulse to the subtraction input of the reversible counter 2, its output code decreases by one. At the same time, the signal and ,, is reduced by the value of iUj. . As a result, the signal U is reduced by. .

These changes in the signals occur until, when the t-th pulse is input to the input,

0

measurement error, due to the identity and illegality of the frequency characteristics of the communication probes, the switch and the quadratic detector, resulting in improved measurement accuracy in the frequency range.

The NIN reversible counter / I will not fulfill the condition Pz Ug.

Claims (1)

When the condition is met, the comparator 22. switches to the logical zero state. Inverter 25 inverts the output signal of comparator 22 and opens the second AND 26 element, which transmits pulses from the generator 24 output to the addition input — the formula of the invention of the versatile counter 21. With the arrival of , (t + 1) th pulse to the input of the addition of the reversible counter 21 its output code is increased by one. AT A device for measuring the modulus and phase of the complex coefficient of a two-pole network, containing a series-connected signal generator and a four-probe sensor with communication probes, the output of which is an input for connecting a two-pole network, the switch, the signal inputs of which are connected to the communication probes of a four probe sensor the control input is with the first output of the control unit, and the output is with the input of a quadratic detector, a series-connected band-pass filter, a linear amplitude detector, a controllable voltage divider, the control input of which is connected to the synchronization output of the signal generator, and a module indicator connected in series to the fa- A meter, the measuring input of which is connected to the output of the bandpass filter, and the control input to the second output of the control unit, and a phase indicator 35, characterized in that, in order to improve the accuracy of measurements in the frequency range, the series-connected knots, the first input of which is connected to the output of the quadratic detector, a comparator, the first element I, a reversible counter, a memory unit and an analog-to-digital converter connected to the second input of the multiplication unit, and op and second element And, the second inputs of the first and second elements AND are connected to the output of the input pulse generator; , the third input is to the first output of the control unit, and the fourth input is to the synchronization output of the signal generator. as a result, the signal U is increased by the value of uU. and the signal -C - by the value of U, which leads to the fulfillment of the condition U ,. Further, the device for measuring the modulus and the phase of the complex reflection coefficient of a two-pole device in the interval 0 t: T / 4j works in a similar way. In the steady state calibration mode, the signal U. oscillates relative to the reference signal Ug with an amplitude AU. and. Similarly, operation occurs at other time intervals corresponding to the inclusion of probes 5–7 and at other operating frequencies of generator 1. In the calibration mode, the indicator 18 indicates a value close to zero, corresponding to the module of the reflection coefficient of the matched load. The repetition period of the pulses produced by the generator 24 is chosen to be longer than the time required for the single operation of the comparator 22, the inverter 25, the elements 23 and 26, the reversible counter 21, the block 12 and the digital-analog converter 13. Expression (4) shows that in the measurement mode, the signal provides correction for the measurement error of the modulus and phase of the reflection coefficient, due to the non-identical characteristics of the probes 4-7 of the four-probe sensor 3 and the channels of the switch 8 ,. as well as the non-uniformity of the frequency characteristics of the probes 4-7, the switch 8 and the quadratic detector 10. This embodiment of the device for measuring the modulus and phase of the complex reflection coefficient of a two-port network provides automatic correction of measurement error, due to the identity and illegality of the frequency characteristics of the communication probe, switch and quadratic detector, resulting in improved measurement accuracy in the frequency range. Formula of Invention B Formula of invention five 0 25 thirty A device for measuring the modulus and phase of the complex coefficient. bipolar array, containing a series-connected signal generator and a four-probe sensor with communication probes, the output of which is an input for connecting the two-port circuit being investigated, the switch, the signal inputs of which are connected to the communication probes of the four-probe sensor, the control input with the first output of the control unit output — with the input of a quadratic detector, a series-connected band-pass filter, a linear amplitude detector, a controlled voltage divider, whose control input is connected n to the output ge- n.eratora synchronizing signal and modulation indicator, the Optional series connected. A meter, the measuring input of which is connected to the output of the bandpass filter, and the control input to the second output of the control unit, and a phase indicator 35, characterized in that, in order to improve the accuracy of measurements in the frequency range, the series-connected knots, the first input of which is connected to the output of the quadratic detector, a comparator, the first element I, a reversible counter, a memory unit and an analog-to-digital converter connected to the second input of the multiplication unit, and op and second element And, the second inputs of the first and second elements AND are connected to the output of the input pulse generator; , the third input is to the first output of the control unit, and the fourth input is to the synchronization output of the signal generator. 40 45 50 55