电子测试
電子測試
전자측시
ELECTRONIC TEST
2012年
4期
9-13
,共5页
正交幅度调制%载波恢复%判决反馈环%频偏相偏补偿
正交幅度調製%載波恢複%判決反饋環%頻偏相偏補償
정교폭도조제%재파회복%판결반궤배%빈편상편보상
QAM%carrier recovery%DD-PLL%frequency offset and phase offset compensation
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。
高階正交幅度調製（QAM）繫統中，隨著QAM信號階數的提高，頻偏和相偏對繫統解調性能的影響越敏感，其對同步性能的要求也越來越高。因此，必鬚在接收耑對繫統中的頻偏和相偏進行更精確的補償，使得接收耑與髮送耑的載波信號達到同頻同相，來提高解調繫統的性能。本文首先簡單介紹瞭兩種常用兩種麵嚮判決的載波相位恢複算法，併利用MATLAB／Simulink為該算法搭建瞭繫統倣真模型進行分析，然後給齣瞭具體的實現方法併對其性能進行瞭分析。倣真結果錶明，麵嚮判決的載波恢複算法實現簡單，穩態時抖動較小，非常適用于高階QAM解調繫統。
고계정교폭도조제（QAM）계통중，수착QAM신호계수적제고，빈편화상편대계통해조성능적영향월민감，기대동보성능적요구야월래월고。인차，필수재접수단대계통중적빈편화상편진행경정학적보상，사득접수단여발송단적재파신호체도동빈동상，래제고해조계통적성능。본문수선간단개소료량충상용량충면향판결적재파상위회복산법，병이용MATLAB／Simulink위해산법탑건료계통방진모형진행분석，연후급출료구체적실현방법병대기성능진행료분석。방진결과표명，면향판결적재파회복산법실현간단，은태시두동교소，비상괄용우고계QAM해조계통。
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.
