Multi-h CPM遥测信号的定时频率联合估计技术

Joint Symbol Timing and Frequency Synchronization Technology for Multi-h CPM Telemetry Signals

针对Multi-h CPM(Multi-h Continue Phase Modulation,多指数连续相位调制)遥测接收机的符号定时和载波频率同步问题,在分析MLSD(Maximum-likelihood Sequence Detection,最大似然序列检测)度量值是符号定时偏差和频率偏差的凸函数的基础上,提出一种基于迟/早门和升/降频门的符号定时和频率同步联合估计算法,通过似然值比较,对符号定时偏差和频率偏差进行迭代估计;并对该算法进行仿真,得到不同参数下的同步性能,给出同步参数选择建议。仿真结果表明:将该算法应用到Multi-h CPM遥测系统中,可实现低信噪比信号的快捕和高精度同步。

Following analysis of the measurement of MLSD （Maximum Likelihood Sequence Detection） as the convex curve of symbol timing deviation and frequency offset, this paper presents a new technique of joint symbol timing and frequency synchronization based on early or late gates and frequency up or down gates to solve the problem of symbol timing and frequency synchronization of Multi-h CPM （Continue Phase Modulation） for telemetry receivers. Symbol timing deviation and frequency offset are iteratively estimated by comparing the likelihood measurements. The performance of the proposed synchronizer was acquired by simulation and appropriate parameters are recommen- ded. Simulation results demonstrated that the proposed synchronizer achieved promising performance even at low signal to noise ratio when applied to a Multi-h CPM telemetry system.