基于FFT的PN码同步系统仿真

摘要

PN码序列同步是直接序列扩频通信系统中的一项关键技术,在高动态多普勒存在的条件下,传统的伪码捕获方法捕获时间较长,运算量较大.提出基于分段式数字匹配滤波器和FFT捕获相结合的捕获方法,仿真结果表明其在不增加硬件复杂度的情况下,能够大幅度地缩短捕获时间,降低系统复杂度.采用SIMULINK构建的模型原理清晰,具有良好的演示效果,为PN码同步仿真提供了一个较好的软件平台.%PN code synchronization is one of the key techniques in direct sequence spread spectrum (DSSS) communication system,the traditional PN code acquisition method would require a fairly long time and large quantity computation in highly dynamic Doppler shift situation.A acquisition method based on the combination of Segments Digital Matched Filter(SDMF) and Fast Fourior Transform(FFT) is suggested. The simulation results shows that it could radically reduce the acquisition time and system complexity without additional hardware complexity. The principle of model built by SIMULINK is clear,and the displaying effect is good, which provides a great software platform for PN code synchronization simulation.