基于Gardner算法的抗载波偏差的一种改进算法

提出了一种用于数字通信接受端TED(Timing Error Detector)模块的算法,它是基于已被广泛使用的Gardner算法的一种改进算法,改进后的算法解决了Gardner算法受载波偏差影响的问题。发现了载波偏差对Gardner算法的影响随载波偏差的增加呈周期性变化的特性。改进的原理是根据这个特性,把载波偏差搬移到对TED模块影响最小的周期区间内,这样可以在不求出载波偏差具体值的情况下消除载波偏差对TED模块的影响。仿真表明,按照以最佳采样点附近Gardner表达式的斜率代表精确度这个标准,改进后的算法提高精确度30%～93%。

An improved algorithm against carrier error based on Gardner's algorithm

An improved algorithm used in digital communication receiver TED(Timing error detector) module is introduced to solve the problem that the widely used TED algorithm,Gardner’s algorithm,deteriorates when carrier error exists.The improvement is based on the discovery that the impact of carrier error on Gardner’s algorithm is periodical as the carrier error increases.The improved algorithm utilizes this feature,and shifts the carrier error to the area of period where the impact is minimized,and thus counteracts the impact without knowing the value of the carrier error.Simulation results show that the improved algorithm makes an improvement of 30%~93% in accuracy,according to the criterion of using slop of Gardner expression near best sample time as indicator of accuracy.