基于相关鉴频器的载波同步算法

通过对整周期扩频的DS/SS系统伪码分段匹配滤波器的相关峰值与载波多普勒频差之间关系的分析,提出了一种基于分段匹配滤波器的相关鉴频算法,其频率捕获范围为0.75倍数据速率,工作上限可达1倍数据速率.通过计算机仿真对比分析了相关鉴频和四相鉴频的无噪鉴频特性和鉴频输出信噪比,给出了一种相关鉴频器和四相鉴频器的组合载波同步方案.仿真结果显示,与传统的四相鉴频器载波同步方案比较,新方案可缩短大初始频偏下载波同步过程.

Correlator frequency discriminator based carrier synchronization algorithm

The effect of large frequency offset on the performance of a digital segmented matched filter(SMF) DS/BPSK receiver is investigated,and an SMF based frequency discriminator is presented.The proposed algorithm employs the outputs of the segmented correlator and the whole period correlator to form a correlator frequency discriminator(CFD) which has a tracking range of 0.75 times the symbol rate and maximum working range up to symbol rate.The noiseless characteristics and outputs of SNR of CFD and four-quadrant frequency discriminator(FQFD) are explored.Then a combined frequency synchronization scheme is recommended for DS/BPSK receivers with a large initial frequency error,which extends the frequency search bin and shortens the carrier acquisition time.