直接序列扩频系统中的一种新PN码跟踪环

提出一种新颖的全数字PN码跟踪，该跟踪环采用符号判决电路和数字序贯滤波器取代经典的环路滤波器来提高衰落环境下的跟踪性能。通过将定时调整过程等效为一时间离散取值离散的齐次马尔可夫链，导出了瑞利衰落下该环路定时误差的稳态概率分布，并对该结果进行了计算机仿真验证，给出了定时误差稳态概率分布、平均失锁时间与定时误差标准偏差的数值结果及分析。

A New Tracking Loop for Direct Sequence Spread Spectrum Systems

A new full_digital non_coherent delay_locked loop (NC_DLL) with a binary digital phase detector and a digital sequential filter is proposed for PN code tracking in direct_sequence spread_spectrum systems. By modeling the timing error process as a discrete time, discrete variable Markov process, the steady_state probability distribution under Rayleigh fading radio channel is obtained, and the results are confirmed by computer simulations. Furthermore, some numerical results of the mean time to lose lock (MTLL), the standard deviation of timing error are presented to demonstrate the good behavior of the proposed code tracking loop.