陷波器对DLL的影响及其改进方法研究

Study on Effect of Notch Filters in Pseudo Code Tracking Loop and Corresponding Improvement Methods

陷波器被广泛应用于直接序列扩谱系统中滤除存在于系统工作频段内的干扰,分析了陷波器对伪码跟踪环路的影响。针对陷波器引起的信号时延和畸变问题,提出对本地产生的伪码也进行相应的陷波处理的方法来增加其与接收信号的相关性,同时针对信号畸变导致的能量差值波动大的问题,提出增加能量积分时间的方法。在systemvue2006环境下对提出的方法进行仿真验证,仿真结果表明这两种方法可以有效地削弱陷波器对伪码跟踪环路的影响。

Notch filters are widely used in direct spread spectrum systems to resist interferences within the working band. The effect of the notch filters in pseudo code tracking loop was analyzed in this paper. To resolve the spread signal distortion and time delay problem,the local PN code was notch-filtered to increase the correlation between receiving signal and the local pseudo code. At the same time,to decrease the big fluctuating integral energy,the integral time was extended. Simulations were carried out in systemvue 2006 environment and the results showed the efficiency of the two proposed methods.