适用于高阶QAM解调的载波恢复算法及其实现验证

摘要

高阶正交幅度调制（QAM）系统中，随着QAM信号阶数的提高，频偏和相偏对系统解调性能的影响越敏感，其对同步性能的要求也越来越高。因此，必须在接收端对系统中的频偏和相偏进行更精确的补偿，使得接收端与发送端的载波信号达到同频同相，来提高解调系统的性能。本文首先简单介绍了两种常用两种面向判决的载波相位恢复算法，并利用MATLAB／Simulink为该算法搭建了系统仿真模型进行分析，然后给出了具体的实现方法并对其性能进行了分析。仿真结果表明，面向判决的载波恢复算法实现简单，稳态时抖动较小，非常适用于高阶QAM解调系统。%In the high order quadrature amplitude modulation （ QAM ） system, with the QAM signal order increases, the effect of the frequency offset and phase offset on the demodulation system performance get more bitter, and the synchronization performance requirements are also getting higher. Therefore, we must compensate the system frequency offset and phase offset more precise on the receiver to made the carrier signal of the receiver and sender be the same frequency and phase to improve the performance of demodulation system. This paper firstly introduces two kinds of commonly used Decision Directed （DD） carrier phase recovery algorithm, then use MATLAB/Simulink to build the simulation model of the system to analyze the algorithm, final/y, the concrete realization method and its performance analysis is given. Simulation results show that the DD algorithm is simple and smaller jitter for steady state, fit for high-order QAM demodulation system.