不同数字调制系统符号定时恢复自噪声性能研究

Study of Self-noise Performance on Symbol-timing Recovery in Digital Synchronous Systems

针对同步数字通信系统在符号定时恢复过程中会受到自噪声的影响这一缺点,通过分析GA(Gardner)和ZC(Zero-Crossing)2种符号定时恢复算法的自噪声性能,研究影响其自噪声性能的因素,得出一种通用于M-PSK、M-PAM和M-QAM调制系统的自相关函数表达式.仿真结果表明,应用这种自相关函数表达式可实现对不同调制系统自噪声性能的分析.

Aimed at the drawbacks that the digital synchronous system for recovering the timing symbols is affected by self-noise, the factors of exerting influances on self-noise performance were studied by analysing the selfnoise performance of GA and ZC algorithms on symbol-timing recovery. Finally, the auto-covariance function expression which holds generally various modulations, such as M-PSK, M-PAM, M-QAM, was derived. The simulation results show that the proposed expression can be applied to the analysis of the self-noise performance on various digital modulation systems.