SU1242847A1 - Method of measuring similarity of phase-frequency characteristics of narrow-band four-terminal networks - Google Patents

Abstract

This invention relates to a radio measuring technique. The purpose of the invention is to increase the speed and accuracy of measurement. A device that implements the method contains a tunable high-frequency oscillator 1, a fixed frequency oscillator 2 :, a balanced modulator 3, an exemplary and a measured quadrupole 4 and 5, respectively, mixers 6 and 7 frequencies, transducers 8 and 9 of the phase shift in time; interval, converters 10 and 11 time interval-code, the transmitter 12 difference of the codes and the block 13 registration. The purpose of the invention is achieved by using a test signal in the form of an amplitude-modulated signal with a suppressed carrier, the side frequencies of which correspond to the average frequencies of four-pole bandwidths, re-shaping the carrier in an interval equal to the four-terminal bandwidth. It is possible to operate at a fixed intermediate frequency, independent of the bandwidth of the quadrupoles and resulting in the exclusion of the frequency-phase measurement error. In addition, it becomes possible to use code reading operations. 1 il. c (O (L

Description

The invention relates to radio metering technology and can be used to monitor, control and measure the identity of the phase-to-frequency characteristics (phase response) of narrow-band quadrupoles having different average frequencies and mutually non-intersecting passbands.

The purpose of the invention is to increase the speed and accuracy of measurement.

The drawing shows a block diagram of a device for implementing the method.

The device contains the following nodes: tunable high frequency generator 1, fixed frequency generator 2, balanced modulator 3, model 4 and measured four quadrupoles, first 6 and second 7 frequency mixers, first 8 and second 9 phase shift transducers in the time interval, first 10 and second 11 time interval converters - a code, a calculator 12 difference of codes and a block 13 of registration.

The output of the tunable generator 1 is connected to the first input of the balanced modulator 3 and the first inputs of the first 6 and second 7 frequency mixers. The output of the generator 2 fixed frequency is connected to the second input of the balanced modulator 3 and the first inputs of the first 8 and second 9 transducers of the phase shift in the time interval. The outputs of the balanced modulator 3 are connected to the corresponding inputs of the exemplary 4 and measured 5 quadrupoles, the outputs of which are connected respectively to the second inputs of the first 6 and second 7 frequency mixers, the outputs of which are connected to the second inputs of the first 8 and second 9 respectively of the phase shift transducers in the time interval whose outputs through the corresponding converters 10 and II interval of time - the code is connected to the inputs of the calculator 12 codes, and the output of the calculator is connected to the input of the registration block 13.

With the identity of the phase characteristics of the sample 4 and the measured 5 quadrupole difference

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The phases recorded in block 13 do not change when the frequency of the tunable oscillator changes. If there are deviations of the phase response of the measured quadrupole from that of the sample, then the detected phase difference from the average value appears.

Due to the use of a test signal in the form of an amplitude-modulated signal with a suppressed carrier, the side frequencies of which correspond to the average frequencies of the quadrupole bandwidths, the carrier tuning in the interval equal to the bandwidth of the quadrupoles, work at a fixed intermediate frequency that does not depend on the bandwidth of the quadripoles and causes the exclusion of the frequency-phase error of the FFP measurement, as well as the use of the operation of the subtraction of codes, the proposed method differs with the conventional method that significantly povshaets speed and measuring accuracy.

Claims (1)

Invention Formula A method for measuring the identity of the phase-frequency characteristics of narrow-band quadrupoles, based on the heterodyne method of reducing the frequency of input signals, converting the phase shifts of low-frequency signals at time intervals, and then into codes, characterized in that, in order to improve speed and accuracy of measurement, the test signal is generated in as an amplitude-modulated signal with a suppressed carrier, and the frequency of the entrances; it is chosen equal to the half-sum of the average frequencies of the four-terminal networks and They are used as a heterodyne, and the modulating frequency is equal to their half difference, the carrier frequency is changed in the interval equal to the quadrupole bandwidth, and the modulating frequency is kept fixed, the identity of the phase characteristics is measured as the phase difference at the frequency of the modulating signal.