一种适用于QAM信号的符号定时同步算法

在全数字接收机中,符号定时同步是信号解调的关键技术之一,其性能的好坏直接影响整个算法解调的性能。针对QAM信号的符号定时同步问题,文章在传统最大平均功率算法的基础上,提出一种联合估计方法。利用一种结构简单的插值滤波器对信号进行二倍插值滤波,然后通过最大平均功率算法求出平均功率值最大的点作为最佳采样点,在信噪比较低时,不需要很高的采样率和复杂的算法就能够保证较高的估计精度。仿真结果表明新算法具有运算复杂度低、估计精度高和抗干扰能力强等优点,能够实现QAM信号的快速同步。

A Symbol Timing Synchronization Algorithm for QAM Signal

In digital receivers, symbol timing synchronization is one of the most important process for signal demodulation, and directly affects the performance of the demodulation algorithm. In this paper, an improved united estimation algorithm for the symbol timing synchronization of QAM is presented, based on the maximum mean power estimate algorithm. In this algorithm, a simple interpolation filter is used to make the signal double interpolated first, and then the maximum mean power estimate algorithm is used to find the maximum mean power point as the best sample point. High estimation accuracy without high sampling rate and using complex algorithm can be ensured in low signal-to-noise ratio. The simulation results of this new algorithm indicate that this proposed scheme has low algorithm complexity, high estimation accuracy and strong anti-interference ability, and a fast symbol timing synchronization of QAM can be implemented.