SU1688187A1 - Detection of interchannel decoupling for two-channel meter - Google Patents

Abstract

The invention relates to a technique for measuring at microwave frequencies and can be used for precision measurements of parameters of microwave quadrupoles, as well as for checking and adjusting phase-measuring equipment and ratio meters. The purpose of the invention is to improve accuracy by determining the phase of the separation value. This goal is achieved by determining the position of the inter-channel communication vector. To determine the position of the inter-channel communication vector and its magnitude, phase shifter 4 and polarization attenuator 3 are used, the feature of which is the independence of the magnitude of the phase shift introduced into the microwave path from the specified attenuation. 1 il.

Description

The invention relates to a technique for measuring at microwave frequencies and can be used to determine the magnitude of the isolation between the channels of a two-channel measuring device with precision measurements of the parameters of the microwave quadriple networks.

The purpose of the invention is to improve accuracy by determining the phase of the separation value.

The drawing shows a block diagram of a device that implements a method for determining the magnitude of isolation between the channels of a two-channel measuring device.

A device that implements a method for determining the magnitude of isolation between the channels of a two-channel measuring device includes a reference and measurement 2 generators with RF oscillations, a polarization tunable attenuator 3, a phase shifter 4, a reference channel mixer 5, a measuring channel mixer 6, a vector voltmeter 7. Perv and the output of the reference generator 1 is connected to the second input of the mixer 5 of the reference channel, the second output of the generator 1 is connected to the second input of the mixer 6 of the measuring channel. The first output of the measuring generator 2 is connected to the first input of the mixer 5, the second output of the generator 2 is connected to the input of the polarization attenuator 3, the output of which is connected to the input of the phase shifter 4, the output of the phase shifter 4 is connected

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d

with the first input of the mixer 6. The output of the mixer 5 is connected to the second input of the vector voltmeter 7, the output of the mixer 6 is connected to the first input of the vector voltmeter 7.

The generators 1, 2 set the levels of the signals AI, Aa so that the vector voltmeter 7 works in normal mode. Then attenuator K is introduced by attenuator 3 into the path of the measuring channel, thus reducing the signal level to about the level of the parasitic signal. In this case, the electrical path length remained the same, since the polarization attenuator does not change its phase shift with a change in attenuation. The position of the phase shifter 4 is changed, by introducing an additional phase shift p into the measuring channel path, and the amplitude of the signal measured by the vector voltmeter 7 and the phase on the limber of the phase rotator 4 are recorded. t is the minimum and maximum value A. The value (modulus) of the inter-channel communication vector Kp is determined by the formula

() / (1 $ ° + 1) + Ko (dB).

After that, the phase shifter 4 is returned to the position corresponding to the maximum and the attenuator 3 is returned to the initial state. The phase shift angle V "shown by the phase meter of the vector voltmeter 7 will be the desired angle determining the position of the inter-channel communication vector Kp. If we measure the phase at the position of the phase shifter 4, which corresponds to the minimum of the signal, then 180 ° should be added to the phase shift ty indicated by the phase meter 7 of the vector voltmeter.

When measuring the parameters of the RF-quadrilateral, the vector V (modulus and phase shift) of the quadrupole being included in the measuring path into the open circuit between the generator 2 and the mixer 6 is measured. Century-V

torus V is the sum of two vectors

.- V Ah + Cr,

where is the true value of the modulus and the phase shift angle

X-Ahe1,

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The use of this invention improves the accuracy of decoupling between the channels of a two-channel measuring device and, as a result, increases

the accuracy of measuring the phase shift of quadrupoles with a non-zero attenuation due to a decrease in the nonexcluded systematic error due to the interchannel connection. As a result

at a given level of accuracy, this equipment with a certain dynamic range can measure phase shifts of two-port networks with large attenuation.

Claims (1)

DETAILED DESCRIPTION A method for determining the magnitude of isolation between channels of a two-channel measuring device, comprising presetting in both channels of signals of the same level, changing the signal level in the controlled canal - by an amount equal to the expected isolation value, changing the signal phase in the controlled channel before obtaining the maximum and minimum signal amplitude in it and determining the magnitude of the isolation value by measurement results, characterized in that In order to increase the accuracy by determining the decoupling phase, additionally after measuring the maximum and minimum amplitudes, the phase of the signal in the controlled channel is set to the maximum value of the signal amplitude, the initial value of the signal amplitude in the controlled channel is determined, which is the unlocking phase.