摘要： 针对连续相位调制(CPM)信号定时同步问题，提出一种数据辅助联合直接判决的定时恢复算法。基于CPM信号的PAM分解，由最大似然方法得到序列检测器和定时误差检测器，并构造一阶锁相环用于估计定时误差。采用数据辅助和数据重用的方法实现定时误差的捕获，运用直接判决方法进行定时误差的跟踪。仿真实验结果表明，当定时误差较大时，该算法可克服直接判决方法存在的失锁问题，实现大定时误差范围的定时估计，且降低定时估计和检测时的匹配滤波器的个数，对DVB-RCS2标准中的CPM突发信号仅用3个匹配滤波器就可以实现定时估计，具有良好的定时估计性能及较好的鲁棒性。

关键词: 连续相位调制, 定时恢复, 数据辅助, 直接判决, 定时误差检测器, 锁相环

Abstract: A data aided and decision-directed union timing recovery method for the synchronization problem of Continuous Phase Modulation(CPM) is presented. Based on Pulse Amplitude Modulation(PAM) representation of CPM signals, Timing Error Detector(TED) and sequence detector are got from the method of likelihood function. And a Phase Lock Loop(PLL) that is used for timing error estimation is constructed in the system, timing acquisition is achieved by using the data aided and data reuse method, by using decision-direct method to track the timing error. Simulation experimental results show that the algorithm can overcome the problem of unlock that existed in decision-directed method when the timing error is large, and achieve timing recovery in a wide range of timing error. And it reduces the number of match filter which is used in timing estimation and detection. For the CPM burst signal in DVB-RCS2 standard, it can achieve good timing estimation by using three match filters. The algorithm has good timing estimation performance and robustness .

Key words: Continuous Phase Modulation(CPM), timing recovery, data aided, decision-directed, Timing Error Detector(TED), Phase Lock Loop(PLL)

中图分类号: 

• TP391