A method for testing the modulation characteristics of a uqpsk microwave direct modulator

Abstract

A method for testing the modulation characteristics of a UQPSK microwave direct modulator, using two-way spread-spectrum baseband signals as the input of the UQPSK microwave direct modulator, and carrying out microwave direct collection on its output, through quadrature down-conversion and gating filtering, and then respectively Its in-phase branch and quadrature branch perform rough estimation of time delay, and carry out precise estimation of time delay according to the result of rough estimation of time delay, find the maximum values ​​of the respective spread spectrum autocorrelation values ​​of the two branches, and obtain the respective At the same time, it is also necessary to perform precise phase estimation based on the precise estimation results of time delay to obtain the precise estimation results of the respective phases of the two branches. Finally, according to the maximum value and The accurate estimation results of time delay and phase are respectively obtained to obtain the amplitude unbalance, phase unbalance, absolute time delay and time delay consistency of the UQPSK microwave direct modulator.

Description

technical field [0001] The invention relates to a method for testing the modulation characteristics of a UQPSK microwave direct modulator, which belongs to the spread spectrum measurement communication technology, in particular to a UQPSK (unbalanced quaternary phase shift keying) microwave direct modulator used in a spread spectrum measurement communication system Test method for modulation characteristics. Background technique [0002] For the satellite payloads of many new-generation spread spectrum measurement communication systems represented by the second-generation navigation satellite inter-satellite link subsystem of Beidou, microwave direct modulation technology is widely used in order to achieve good delay characteristic design. , the UQPSK microwave direct modulator is a microwave device that is widely used. It modulates the signals of the measurement and communication branches into the two carriers of the in-phase branch and the quadrature branch according to a ...

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Problems solved by technology

[0007] The technical problem solved by the present invention is: in order to make up for the shortcomings that the existing method cannot analyze the absolute time delay, the time delay consistency and cannot directly test the UQPSK modulation mode and is more sensitive after transformation, and the test result cannot reflect the deviation polarity, a UQPSK is provided The method for testing the modulation characteristics of microwave direct modulators uses two-way spread-spectrum baseband signals as the input of UQPSK microwave direct modulators, and directly collects the output of microwaves, and performs quadrature down-conversion and gating filtering, and then separates the in-phase branch Roughly estimate the time delay of the two branches and the orthogonal branch, and accurately estimate the time delay according to the results of the rough estimation of the time delay, find the maximum value of the spread spectrum autocorrelation value of the two branches, and obtain the time delay of the two branches At the same time, it is also necessary to perform precise phase estimation based on the precise estimation results of the time delay to obtain the precise estimation results of the phases of the two branches. Accurate delay estimation results, accurate phase estimation results to obtain amplitude imbalance, phase imbalance, absolute delay and delay consistency of UQPSK microwave direct modulator

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