基于Laurent分解的GMSK定时同步环路

A Digital Timing Tracking Loop Based on Laurent Representation for GMSK Modulations

定时同步是数字调制信号接收不可或缺的环节。对于GMSK信号定时同步,现有算法多为数据辅助或前馈类算法。从GMSK信号的Laurent分解出发,结合Gardner定时同步环路,提出了一种基于Laurent分解的GMSK信号定时同步环路。该环路采用2 bit差分来提取定时误差,用于控制内插时刻,环路简单,运算量小,易于工程实现。仿真结果表明,即使对于小BT值GMSK信号,该方法依然可以有效提取定时误差,且具有较强的抗噪声性能。

Timing synchronization is an indispensable part in receiving digital modulation signal.Most of the existing algorithms for the timing synchronization of GMSK signals are either data aided or feed forward.In this paper we present a digital timing tracking loop for GMSK modulations.This technique is based on Laurent representation and combined with Gardner timing recovery loop.The loop gets the timing error based on two bit differential detection,and then controls the interpolating. The loop is simple,has little computational complexity,and can be easily implemented.Simulation results show that the timing error can be efficiently extracted even for GMSK with small BT,and the loop has a fine anti-noise performance.