SU1327020A1 - Apparatus for measuring complex coefficient of reflection - Google Patents

Abstract

This invention relates to a radio metering technique and improves measurement accuracy. The device contains a phase shift calibrator 3, a power meter (MI) 4, a measuring probe section 5, a directional coupler 6, a two-port circuit being investigated 7, a computer 8. The serially connected control unit 1 and the delay unit 2 are newly introduced. The signal source is made in the form of a microwave calibrator 3 phase shift. The continuous displacement of the standing wave in the prototype device is replaced by a discrete one, stopping after each elementary displacement. The stopping time, equal to the measurement time of the IM 4, is determined by block 1. Block 2 serves as the delay in the start of operation of the IM 4 for the transient time that occurs in the calibrator 3 when the calibration increment of the phase shift is specified in one of the channels. The measurement results are entered into the computer 8, the C-processes their processing and starts block 1 after the end of each elementary measurement. 1 il. (L

Description

This invention relates to a radio metering technique and can be used to measure impedances at high and ultrahigh frequencies.

. Purpose: the invention is the measurement accuracy ..

The drawing shows the structural electrical circuit of the device for measuring the complex reflection coefficient.

The device contains a control unit 1, a delay unit 2, a phase shift calibrator 3, a power meter 4, a measuring probe section 5, a directional coupler 6, a two-port circuit being investigated 7, a computer 8.

A device for measuring the complex reflection coefficient works in the following manner.

The signal from the first output (first channel) of the phase shift calibrator 3 is fed to the measuring probe section 5, and the signal from the second output (second channel) of the calibrator 3 is fed to the input of the directional branch 6 and. Reflected from the studied bipolar 7, passes into the measuring probe section 5 on the opposite side. In the measuring probe section 5, which performs the function of an adder, a wave appears. If in one of the channels of the calibrator 3 relative to the other channel to set the calibrated increment of the phase shift dv, then the standing wave in the measuring probe section 5 will shift by a jump

Where A is the wavelength.

By setting, for example, the values of / it /., Equal to O, 90, 180 and 270 and measuring the power of the standing wave in the plane of the stationary probe of the measuring probe section 5, we can get an analogue of the four-probe measuring line with the distance between the probes L / four. The values of phase shifts can be set, the number of which in the range of 0-360 ° is selected in accordance with the measurement algorithm adopted. . Thus, the continuous displacement of the standing wave in the prototype device is replaced by a discrete one.

five

0

after each elemental displacement. The stopping time, equal to the measurement time t of the power meter 4, is determined by the control unit 1. Block 2 serves to delay the start of operation of the power meter 4 for the duration of the transition process that occurs in the calibrator 3 when

setting / dV in one of the channels. The measurement results from the power meter 4 are entered into the computer 8, which processes them and starts the unit, after the control

each elementary measurement.

The amplitude of the resultant signal in the probe section 5 is determined by the sum of two signals U, and Ui, + U2 U, sin (cjt + 6,) + Uj / y sin (ujt + 0 + in +), (1)

where U iUjin 6 are the amplitudes and initial phases of the signals of the two channels of the calibrator 3, respectively;

G, the modulus and phase of the reflection coefficient from the two-terminal circuit 7 under study; & (f is the calibrated increment of the phase shift.

4 power meter readings for each measurement

 X; kGi Xtf2i, „, cos (0, -t, -d (f,),. (2).

where K is the transmission coefficient of the probe.

0 For different i, by specifying different 4 (., We get a system of nonlinear equations (2) with four unknowns: fx f-fx The values of K () are determined during calibration. The required number of equations of the form (2) are determined by the modulus and phase reflections of gu and if.

There is no dynamic measurement error in this device.

0

Formulas and inventions

A device for measuring complex reflectance coefficient -1, containing a series-connected signal source, a measuring probe 5 s section and a directional coupler, the output of the main arm of which is the output for connecting the probe 31327020

bipolar circuit, and the output of the auxiliary shift, and introduced successive shoulder connected to the second connected control unit and

output of the signal source, measure-delay unit, the output of which, the power coupler, is different with the control input of the meter

e with the fact that, in order to increase the power, while the output of the measurement control unit, the signal source is connected to the control input

made in the form of a microwave calibrator phase-microwave calibrator phase shift.

Claims (1)

Claim A device for measuring the complex reflection coefficient, containing a signal source connected in series, a probe section and a directional coupler, the output of the main arm of which is the output for connecting the studied two-terminal device, and the output of the auxiliary arm is connected to the second output of the signal source, the power meter, characterized in that, in order to increase the accuracy of measurements, the signal source is made in the form of a microwave phase-shift calibrator, and series-connected nnye control unit and the delay unit, the output of which is connected to the control input of the power meter, wherein the control unit output is connected to the control input of the microwave calibrator phase shift.