SU1191843A1 - Apparatus for measuring modulus and phase of complex reflection ratio of microwave two-terminal network - Google Patents

Abstract

A DEVICE FOR MEASURING A MODULE AND PHASE OF A COMPLEX COEFFICIENT OF REFLECTION MICROPHONE CUP CABLES, which contain series-connected SBS-generator and a segment of a transmission line with a four-probe sensor, the outputs of the probes are connected to the corresponding inputs of the microwave switch, which quadrants are connected to the quad core of the quadcopters, the probe outputs of which are connected to the corresponding inputs of the microwave switch, which quadrants are connected to quadrants of the probe, which are connected to the corresponding inputs of the microwave switch, which quadrants are connected to quadrants of the probe, which are connected to the corresponding inputs of the microwave switch, which quadrants are connected to the quad core, and the quadrants of the probes are connected to the corresponding inputs of the microwave switch. and the first indicator, as well as a linear amplitude detector, whose input is connected to the output of a bandpass filter, a control unit, the output of which is connected to the control input of the microwave switch and the second input of the phase meter, and the second indicator, while the output of the transmission line segment with the four-probe sensor is an output for connecting the microwave two-pole device being studied, characterized in that, in order to improve the accuracy, between the output of the quadratic detector and the input of the second indicator is connected in series with the low-pass filter and the dividing unit, the other input of which is connected to the output of the linear amplitude (L of the detector). QO CX) 4 GS

Description

The inventions relate to radio metering technology and can be used in automatic measuring systems and instruments for embedded control.

The aim of the invention is to improve the accuracy.

The drawing shows the structural electrical circuit of the device for measuring the module and the phase of the complex reflection coefficient of the microwave two-port network.

The device contains series-connected microwave generator 1, a segment 2 of the transmission line with a four-probe sensor, the microwave two-terminal 3 under study, probes 4-7 of a four-junction sensor connected to the corresponding inputs of the microwave switch 8, the control input of which is connected to the first output of the control unit 9 . The output of the microwave switch 8 through a quadratic detector 10 is connected to the inputs of a band-pass filter 11 and a low-pass filter 12, and the output of a band-pass filter 11 to the inputs of a linear amplitude detector 13 and a phase meter 14, the second input of which is connected to the second output of control unit 9, output the low-pass filter 12 is connected to the input of the division unit 15, the second input of which is connected to the output of the linear amplitude detector 13, and the output to the second indicator 16, the first indicator 17.

A device for measuring the modulus and phase of the complex reflection coefficient of microwave bi-poles operates as follows.

The Zpad signal from the microwave generator 1 enters a segment 2 of the transmission line with a four-probe sensor to the microwave two-pole 3 under study with some complex reflectance

G | G | eL

"

where | r | - modulus of reflection coefficient;

F is the phase of the reflection coefficient.

The reflected wave Uo interferes with the incident one. Field distribution analysis is carried out using probes 4-7 of a four-probe sensor placed in different sections so that the phase incursions between them are n / 4. The signals at the outputs of the probes 4-7 are determined by the known ratios

U4 KiU «Vl + ir | +2 | r | sin9Cos (o) t + Vi);

. + 1II + 2 | T | sozfbO5 (a.1 + U2);

U6 + KiU "- / l-f | G | -2 | r | sin (pcos (a) t-fV3); U7 KiUnVl + irP-2 | G1So8f & 05 ((ot + V-1-); g (1 + | G | CH2 | G | -5TF + 1 + 1Г1 +2 | Psozf + 1-f | r | -2 | f | siny-h | + 4

where (O is the frequency of the microwave signal;

t is the current time;

The CG is the transmission coefficient of the probe of the four-probe sensor assuming that all the probes are identical; Un is the amplitude of the incident wave; Vi-V4 is the initial phase of the U4-Ib- signals. The high-frequency voltages U4-U from the probes 4-7 are fed to the input of the microwave switch 8, which periodically commutes with the frequency Qf 25t / T each of the output signals of the probes 4-7 to the common channel. In this case, the output of the microwave switch. 8, a signal is received in the form of a periodic sequence of radio pulses. This signal is detected by a square-law detector 10. The output signal of a square-law detector 1Q is a periodic function, which in the interval equal to the switching period is

К | К2Кзи (1 + | Г | Ч2 | Г | 51Пф) at. К | К2Кзи ° (1+ | ПЧ2 | Г | со5 (р), with “I-,

t К | К2Кзи; (Ц-1П -2 | ГЫпф), with t К | К2Кз1 / l (1- | - | гГ-2 | Псо5 (р), with

where Ka is the transmission coefficient of the microwave switch 8 in the "on" state. Kz - conversion factor

quadratic detector 10. Band-pass, filter 11 tuned to Q frequency C selects the first harmonic of the output signal Us of the quadratic detector 10 K2KzK4i „| Г Icos (H1-f + / 4),

where K4 is the transmission coefficient of the bandpass filter 11 at the frequency O.

At the same time, the voltage from the output of the quadratic detector 10 is fed to the input of the low-pass filter 12, which selects the constant component of the signal.

f -iJU "(t) dt

OR

fit

  K, K2KzK4i (1 + 1PCH2 | G | 5Shf)

45o

5/4

xdt + 4 К1К2Кзи (1 + 1Г | Ч2 | Г1со5ф) х

/ "/

vdt + ij К1К2Кзип (1 + 1П2т / г,

xdt + f 5 К1К2Кз1Л (Ц- | Г | ЗГ / 4: xd-fc Д А. л | fl-2lflcosq) nTn f J-KiK2K3Uri {l + ir | ).

The output voltage of the low pass filter 12 is

U, o KiK2K3K5Ut (l + | r | 2),

where Ks is the transmission coefficient of the 12 low-pass filter on the direct current.

The voltage at the output of the linear amplitude detector 13 has the form

Un + KlK2K3K4K6Un | f |,

where KB is the linear gain coefficient of the amplitude detector 13, then the signal at the output of block 15 is equal to

and, 2 К7Л

. K, K9K K4KVI | G |

K1K2KzK5Sh (1 + | YY)

WK4KbK

K5 (14-1PT

1G1

Thus, in the last expression, the coefficients Ki, K2, Kz and the value of the amplitude of the incident wave (and „) are absent, i.e. completely eliminated dependence

the measurement result from the transmission coefficients of the four-probe sensor of the microwave switch 8, and most importantly the conversion coefficient of the quadratic detector 10. In addition, the dependence of the result is excluded

measurements from changes in the level of the microwave frequency, the value of the microwave generator. The latter is important in that it allows us not to be used in ystpjoctvs to measure the reflection coefficients of automatic power control systems.

The voltage from the output of the bandpass filter 11 is fed to the input of the phase meter 14, at the output of which the voltage is

Ul3 K8F1

phase transfer coefficient KB - meter 14.

Voltages Ui2 and Uia are supplied to the second indicator 16 and the first indicator 17, respectively, which are calibrated directly to the values | Г | and f.

Due to the nonlinear dependence between the voltage Ui2 and the measured value | Г | Use the second indicator 16 with a non-linear scale.

Claims (1)

DEVICE FOR MEASURING THE MODULE AND PHASE OF THE COMPLEX REFERENCE OF MICROWAVE DOUBLE-POLE CONTAINERS, which contains a series-connected microwave generator and a segment of a transmission line with a four-probe sensor, the outputs of the probes of which are connected to the corresponding inputs of a microwave switch, to the output of which a square-wave filter is connected; , a phase meter and a first indicator, as well as a linear amplitude detector, the input of which is connected to the output of the bandpass filter, a control unit, the output of which is connected to the control the input of the microwave switch and the second input of the phase meter, and a second indicator, while the output of the transmission line segment with a four-probe sensor is an output for connecting the studied microwave two-terminal device, characterized in that, in order to improve accuracy, between the output of the quadratic detector and the input of the second indicator consistently included a low-pass filter and a division unit, the other input of which is connected to the output of a linear amplitude detector.