群时延失真对QPSK系统误码性能影响的仿真与分析

Simulation and Analysis of Influence of Group Delay Distortion on Performance of QPSK Communication System

群时延失真是影响卫星通信误码性能的重要因素之一。首先介绍了群时延的概念和表达式以及卫星信道群时延失真模型,然后根据最小相位系统的系数和复倒谱系数之间的关系,设计了线性群时延和抛物线群时延滤波器,利用MATLAB/SIMULINK仿真软件包,建立了两种群时延失真信道模型,对QPSK调制信号在群时延失真信道特性下进行了仿真,得出了两种群时延失真对系统误码性能的影响。

Group delay distortion is one of the most important factors which affect the BER （bit error rate） performance of satellite communication. The concept and expressions of group delay and satellite group delay channel model were first introduced and then the linear and parabolic group delay filters were designed based on the relationship between the group delay function and the cepstral coefficients. Some models for simulation in MATLAB/SIMULINK were established, including linear and parabolic group delay channel. The degradation of system BER caused by linear and parabolic group delay was obtained.