一种用于全数字化QPSK解调的大频偏矫正算法

An Algorithm for Rectifying Large Frequency-Offset in Fully Digitized QPSK Demodulation

在全数字化QPSK解调器中 ,有时存在着相当大的相对载波频偏 ,导致接收机不能正常工作 .本文提出了一种新的算法 ,该算法将对频偏的直接估计转换成对一个新序列的周期进行估计 ,达到对大频偏进行有效估计并矫正的目的 ,解决了这一难题 .此算法计算量较小 ,统计特性好 ,已在用单片DSPTMS32 0C6 2 0

In fully digitized QPSK (Quadrature phase shift Keying) demodulator,sometimes th ere exists a rather large freque ncy-offset so that the demodulator can not work normally.This paper proposes a novel algorithm to solve this challenging problem.Instead of estimating frequenc y-offset directly,we estimate the period of some new sequence,resulting in a go od statistic for frequency-offset estimating.The algorithm is less expensive co mputationally in rectifying frequency-offset,and has been applied to a multi-c hannel QPSK demodulation system,which is implemented with a single DSP(Digital s ignal processing) of TMS320C6201.