DSSS数字接收机的AFC算法及其实现

AFC Algorithm for Direct-sequence Spread Spectrum Digital Receiver and Its Implementation

介绍了一种零中频直接序列扩频 (DSSS)数字接收机的自动频率控制 (AFC)算法及其仿真和实现。该算法从残留载波跟踪解调环的鉴相信号中提取频偏信息 ,对下变频本振进行AFC ,并且可根据对频偏的估计切换环路特性 ,使环路既有较大的捕获带宽 ,又具有较好的跟踪和滤波性能。该算法适用于无导频的直扩BPSK信号接收机 ,其特点是算法复杂度低 。

This paper introduces an AFC algorithm for a zero-intermediate frequency direct-sequence spread spectrum digital receiver. In this algorithm, frequency offset information obtained from phase detecting of a carrier tracking loop is used to control automatically the frequency of local oscillator so as to gain better despreading and demodulating performance. This AFC algorithm is suitable for DSSS/ BPSK signal receiver. Its characteristics are high receiving sensitivity and less complexity. It is especially convenient for a FPGA implementation.