一种改进的定时恢复方法  

A modified method for timing recovery

作　　者：李滚[1] 王瑞红[1] 秦开宇[1] 李文娟[1] 

机构地区：[1]电子科技大学空天科学技术研究院,成都610054

出　　处：《电子测量与仪器学报》2009年第7期46-50,共5页Journal of Electronic Measurement and Instrumentation

基　　金：国家自然科学基金(编号:60672029)资助项目

摘　　要：定时恢复是全数字接收机中的一项关键技术,以传统的Gardner定时恢复理论为基础研究了一种改进的定时恢复方法。该方法去掉环路滤波,改插值滤波器为多相滤波器,并对NCO和定时误差提取方法进行了改进。以16QAM为例对整个环路进行了仿真验证,该方法对载波相位不敏感,并且较传统Gardner插值算法简单易行。在满足准确性和速度的前提下,由于采用连续可变分数倍抽取技术,该方法在工程应用中可适用于每个符号非整数个采样点的信号的定时恢复,同时能有效避免多电平信号在采用Gardner算法估算定时误差时出现的局部抖动现象,适用于PSK、QAM信号的定时恢复。Timing recovery is a key technology to all-digital receivers. Based on the conventional theory of Gard- ner timing recovery, a modified timing recovery method is proposed. In this approach, the loop filter is removed, and the interpolation filter is replaced with the poly-phase filter. Furthermore, the NCO （Numerically Controlled Oscillator） and timing error extraction are modified respectively. Moreover, taking the 16QAM signal for instance, the method of design and accomplishment are simulated and evaluated. The simulation results indicate that this method is not sensitive to carrier phase but simpler than conventional Gardner interpolation algorithm. Under the premise of accuracy and ac- quisition speed, the method has the advantage of non-integer sampling point per symbol signal for adopting the con- tinuously variable fractional rate decimator technology in engineering, and the local dithering phenomenon induced by the Gardner algorithm to multilevel signal can be efficiently avoided, it is also suitable for the signal of PSK and ASK.

关 键 词：定时恢复 PSK QAM GARDNER算法 

分 类 号：TM935.21[电气工程—电力电子与电力传动]