SU1350623A1 - Reflection factor modulus meter - Google Patents

Abstract

This invention relates to a radio metering technique and provides improved measurement accuracy. Measuring module mod. the reflection contains a microwave generator 1, eight directional couplers (BUT) 2-7, 11 and 12, valve 8, modulator 9, generator 10 of modulating voltage, modulator 5 liters, phase encoder; actor 16, attenuator 17, digital phase meter (Tsf) 18, converter 19 codes, digital indicator 20, phase dis-; the criminator 21, the integrator 22 and the adjustable phase switch; a tangent (RFV) 23. A part of the energy of the microwave generator 1 branches the HO 2-4 to the heterodyne inputs of the respectively. demodul torus 13-15. Another part of the energy passes through the HO 2-4, is modulated in the modulator 9 by the scrap of the generator 10, passes through the HO 5, gate 8, HO 7 and RFV 23 to the test load 24, is partially reflected from it and then passes through RFB 23, HO 7 , 6, and 11, demodulator 14, and arrives at TF 18. Continuously; The signal on the CF 18 is a part of the sum of the reference modulated signal and the modulated microwave signal, represented by the signal, its signal partially reflected from the load 24 and the valve 8. The CF 18 measures the phase of the sum signal, the carrier (L

Description

information about the module of the complex coefficient, the reflection of the load, relative to the phase of the signal, deconstructor it with: demodulator 15. With. RFB 23 and a circuit from BUT 7, an attenuator 17, BUT 12, a demodulator 13 and a phase discriminator 21, which form a control voltage for it,

one

The invention relates to radio measuring technology and may be. used to measure the modulus of the complex reflection coefficient at ultrahigh frequencies.

The purpose of the invention is to improve the measurement accuracy.

The drawing shows the structure-electric circuit: a meter of the reflection coefficient module.

The reflection coefficient meter contains a microwave generator 1, the first 2, the second 3, the third 4, the fourth 5, the fifth 6 and the sixth 7 directional couplers, the valve 8, the modulator 9, the generator 10 modulating its voltage, the seventh 1 and the eighth 12 directional couplers, first 13, second 14 and third 15 demodulators, phase shifter 16, attenuator 17, digital phase meter 18, code converter 19, digital indicator 20, phase discriminator 21 ,. an integrator 22, an adjustable phase shifter 235 whose output is an input for connecting the test load 24,

The reflector modulus meter operates as follows.

The microwave generator 1 generates a microwave signal. Some of the energy is diverted

ej- (t) C (e (t) + eo (t)) CE (cos (cot + m,)) + GtH5, K cosCcot- + m sin (ftt + q 2))) CE (cos (m sin (sjt + q,)) coscot-sin (m sin (Qt +

+ cf,)) sinot + (t sin ($ t + q J jcoscot-Г „Pj. (m sin (Qt +

+ q j) sinG3t CE (cos (m sin (nt + q,)) + G / kK cosSt sin (nt + q 2)))

xcosut- (sin (m sin (ct + tf,)) (m sin (T2t + cf.j))) sinut):

CE cos {ut + in sin (Qt + q g. (Rn))) ,,

(fg. (H) arctg (sincf-, + r, | Hz K sinCfJ /, (cos Cf, + r.rj, C cos (f) |: q, 0 °, Cf

-arctg

E. (EC (EG; g ,, G, K cos (cf, -g.,) F | cf, 0 °, c /, 90 °

 ГЕ + (ЕГ, Г, К) М °; -.

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The constant phase shift 90 between the reference signal at the in-line valve 8 and reflected to the valve from the load 24 is constant. The phase shift of 90 ° corresponds to the maximum measurement accuracy. BUT 11 and phasebreaker 16 eliminate the measurement error due to the final directivity of BUT 7. 1 sludge.

through the secondary channel of each of the first three directional couplers 2-4 to the heterodyne input of the corresponding demodulators 13-15. Another part of the energy of the microwave signal goes to modulator 9, which modulates the phase of the microwave signal by a signal coming to the control input of the modulator 9 from the generator 10.

dulirovanny microwave signal e (t) with

modulator 9 output propagates through the primary channel of the fourth directional coupler 5, valve 8, primary channels of the fifth 6 and sixth 7 directional couplers, adjustable phase shifter 23 to the test load 24 and, partially reflected from it, through adjustable phase shifter 23, primary channels DjecToro 7 and fifth 6 directional couplers fall back to valve 8.

Modulated microwave signal e (t), branched into the channel of the incident wave

through the fifth directional coupler 6, is part of the sum of the reference modulated microwave signal ep (t) and the modulated microwave signal e (t), which is partially reflected from the valve 8 and from the test load 24, the reference modulated microwave signal e ( t).

31350623

С - transient weakening

directional coupler 6; E is the signal amplitude e (t); CO is the value of the frequency of a non-microwave microwave signal, at which the modulus of the complex coefficient G is measured, the reflection of the test load 24; ha is the index at the head of the modulation; IQ I - the value of the modulating frequency of the output signal of the generator 10;

t is the FULL time; If, - the initial phase of the signal, mod ig

emitting a microwave signal e (t); (jf is the initial phase of the high frequency signal modulating the microwave signal e, (t);

G is the modulus of the complex reflection coefficient of the valve 8; K - attenuation coefficient

driven phase shifter 23; Hz) is the initial phase of the high frequency signal modulating the jc microwave signal e (}. Consequently, the module of the complex reflection coefficient G exploring the load 24 can be represented as a function of the phase measured by digital phase meter 18,

thirty

r ,, K2. (one)

The digital phase meter 18 measures the phase C) (D) of the digital phase meter 18 arriving at the first input from the output of the second demodulator 14 of the modulating signal extracted by the second demodulator 14 of the incident wave from a part of the modulated microwave signal e (t tied to the channel of the incident wave through the fifth directional coupler 6, the primary channels of the seventh directional coupler P to the input of the second demodulator 14. Phase c., - (D) is measured with respect to the phase c of the digital mode 18 coming to the second input of the third demodulator 15 reference mode of the third demodulator 15 from the part of the modulated microwave signal e (t), replied to the channel of the reference wave through the fourth directional coupler 5 to the input of the third demodulator 15.

Thus, the digital phase meter 18 generates a voltage at the output, which is a function of the module of the complex coefficient G „of the reflection of the test load 24. The phase difference

c

0

5 0 5 0

five

(cj) | -c () between the reference signal modulating the microwave signal e (t), acting at the input of the valve 8, and the signal modulating the microwave signal eo (t), propagating from the input of the controlled phase shifter 23 to the output valve 8, is maintained constant and equal to 90 with the help of an adjustable phase shifter 23. Phase shift 90 corresponds to the maximum measurement accuracy of the modulus of the complex coefficient G of reflection of the test load 24.

The control of the adjustable phase shifter 23 is carried out as follows.

A part of the reflected energy - from the studied load 24 of the modulated microwave signal, passed through the adjustable phase shifter 23, branched into the channel of the reflected wave through the sixth directional coupler 7. Next, this signal through the attenuator 17, introducing attenuation equal to the attenuation of the microwave signal in the GB phase shifter and the eighth directional coupler 12 is fed to the input of the first demodulator 13. The extracted signal from the output of the first demodulator 13 is fed to the first input of the phase discriminator 21, the second input of which receives the reference modulating signal.

When the phase difference deviates from 90 °, an error signal is generated at the output of the phase discriminator 21, which through the integrator 22 changes the phase introduced by the adjustable phase shifter 23 until a zero voltage is established at the output of the phase discriminator 21, which corresponds to the phase shift 90 input modulating signals. To eliminate the error in measuring the phase shift due to the final directivity of the sixth directional coupler 7, the seventh directional coupler 11 and the phase shifter 16 are introduced, shifting the phase of the microwave modulating signal 180 ° due to the final directivity of the seventh directional coupler 11.

The modulated microwave signals of the incident wave arriving at the input of the first demodulator 13 through the respective paths from the outputs of the secondary channels of the fifth 6 and sixth 7 directional couplers have equal amplitudes in the paths, but their signals are in opposite phase, which leads to their mutual compensation.

The relative measurement error of the reflection coefficient Hz in accordance with expression (1) is determined by the relative measurement error Gu of the reflection of the valve 8 and the instability of the attenuation coefficient K of the controlled phase array; the latter 23. In this case, the last two components can be practically reduced to relative temperature instability characteristics of the materials of which the valve 8 and the adjustable phase shifter 23 are made.

The relative temperature instability of the corresponding coefficients Hz and K is characterized by a value significantly lower than the relative error-measurement of the phase shift. Thus, the relative measurement error of the modulus of the complex coefficient is G. The reflection of the test load 24 can be considered equal to the measurement error of the phase tfj — a digital phase meter 18.

The code converter 19 is a read-only memory in which the tabular values of the complex reflection coefficient modulus G are recorded, corresponding to different values of phase differences measured by the digital phase meter 18. From the output of the converter 19, the information codes are in binary-ten. The code is fed to the digital

. The indicator 20, the measurement result of the module G of the reflection coefficient of the test load 24, is counted on its digital display.

Thus, the reflection coefficient module measures the complex reflection coefficient module n as a function of the phase difference measured by the digital phase meter 18, which can be measured with a relative error of 1 10, for example, using a standard digital phase difference meter.

Claims (1)

Invention Formula A reflection coefficient module meter containing a microwave generator, to the output of which an input is connected the primary channel of the first directional coupler, the second, third, fourth, fifth and sixth directional couplers, a modulating voltage generator connected to the control input of a modulator, the output of which is connected to the input of the primary channel of the fourth directional coupler, and a valve characterized in , in order to increase the measurement accuracy, the first, second, and third demodulators are introduced, the heterodyne inputs of which are connected respectively to the output of the swing wave of the secondary channels of the first, second, and third the taps, the signal input of the third demodulator is connected to the output channel of the oncoming channel of the fourth directional coupler, serially connected digital phase meter, code converter and digital indicator, serially connected phase discriminator and integrator, the output of the first demodulator is connected to the first input of the phase discriminator, the output of the second demodulator to the first input of the digital phase meter, and the output of the third demodulator to the second inputs of the digital phase meter and phase discriminator, the seventh directional coupler, the outputs of the primary channel of which are connected to the signal input of the demodulator, the input of the primary channel is connected to the output of the incident wave of the secondary channel of the linearly directional coupler, the eighth directional coupler, the output of the incident wave of the secondary channel of which is connected to the spiral input of the first demodulator, the output of the primary channel through the input attenuator is connected to the output of the reflected wave of the oncoming channel of the sixth directional coupler, the other output is to of the eighth directional coupler's toric channel through the input phase shifter is connected to the incident output of the secondary channel of the seventh directional coupler, the output of the primary channel of the fifth directional coupler is connected to the output of the primary channel of the sixth directional coupler, the valve is connected between the output of the primary channel of the fourth directional coupler and the input of the primary channel of the fifth channel directional coupler, primary 7 .13506238 the channels of the first, second and third sixth directional coupler under--. directional taps connected connected to the input of the entered control in series, the output of the primary q-phase switch, the output of which The third directional deviating terminal is the output for connecting the sources connected to the signal input 5 of the monitored two-port circuit, and the control modulator, the output of the primary channel of the input is connected to the output of the integrator.