An Orthogonal Modulation Signal Generator for Simulating Doppler Variation

Abstract

The invention discloses a device for generating a quadrature modulation signal for simulating Doppler changes. It consists of a resampling unit, a digital-to-analog converter, a low-pass filter, and an upconverter. The device relates to the generation technology of the test modulation signal in the field of communication. It samples the external input data, generates the required Doppler frequency offset and Doppler code offset in the digital IF modulation signal according to the Doppler change rate control word and the Doppler scanning range control word, and finally passes the digital-to-analog conversion After processing by filter, low-pass filter and up-converter, a quadrature modulation signal simulating Doppler change is finally generated. The invention realizes the cooperative simulation of the Doppler frequency deviation and the Doppler code deviation of the orthogonal modulation signal, and improves the smoothness and reliability of the change of the Doppler frequency deviation and the Doppler code deviation in the signal.

Description

technical field [0001] The invention relates to the field of satellite data transmission, and is particularly suitable for use as an orthogonal modulation signal generating device for simulating satellite Doppler changes in the satellite data ground receiving station test subsystem. Background technique [0002] The main functions of the satellite data ground receiving station test subsystem include generating quadrature modulation signals for testing simulated satellite Doppler changes, which are used to complete the test task for the ground receiving station data receiving subsystem. [0003] The traditional quadrature modulation signal generating device for simulating Doppler change has some disadvantages in the process of simulating Doppler change. First of all, traditional devices use different circuits to realize Doppler frequency offset simulation and Doppler code offset simulation respectively. Since different circuits are independent of each other, they cannot refle...

AI Technical Summary

Problems solved by technology

First of all, traditional devices use different circuits to realize Doppler frequency offset simulation and Doppler code offset simulation respectively. Since different circuits are independent of each other, they cannot reflect the relationship between Doppler frequency offset and Doppler code offset. In addition, when the traditional device simulates Doppler frequency offset, it needs to use DDS chip setting or frequency synthesis decimal frequency division to realize, but these two kinds of circuits need to be continuously configured in the frequency registers of their respective circuits when they are implemented. The frequency control word, thereby changing the current carrier frequency value, because the carrier frequency in the Doppler frequency offset phenomenon is continuously changing, and the traditional method needs to occupy a certain set time interval to change the carrier frequency value, so it cannot Smooth analog Doppler frequency deviation; finally, traditional devices mostly use digital-analog hybrid circuits when they are implemented, the peripheral circuits of the device are complex, and circuit debugging is difficult

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