基于脉冲调制的卫星射频测试系统变频链路群延时参数校准

群延时参数是变频链路的关键指标之一，本文主要研究卫星射频测试系统变频链路群延时参数校准方法。卫星射频测试系统是卫星地面测试设备的重要组成部分，其变频链路的群延时特性对卫星测距功能测试及信号的传输质量具有重要意义；从群延时定义出发，讨论了群延时的测试原理和方法，提出并实现基于软件无线电技术的调制法测量群延时，该方法特别适用于内本振无法接入的变频系统群时延的精确测量；详细说明调制法的基本原理并研建校准装置。实验表明调制法测量群延时具有较高的精度。

Group Delay Calibration of Satellite RF Test System’s Frequency Converter Link based on Pulse Modulation

Group delay is one of the key performance specification in frequency converter link. Group delay calibration method of satellite RF test system’s frequency converter link is studied in this paper. Satellite RF test system is the important part of Satellite Ground Test Equipment. Its group delay of frequency converter link has important significance for the test of Satellite Ranging and the quality of signal transmission. From the definition of group delay, this paper discussed the test theory and method of group delay and presented the modulation method based on software defined radio technology to measure the group delay. This method is suitable for the precise measurement of frequency converter link that can’t accept other local oscillator. The formula of the modulation method is deduced in detail and the calibrating device is founded in this paper. The result of experiment demonstrate that the modulation method has more precision to measure the group delay.