摘要
针对PCM/FM系统中多数同步方法都需要在接收端添加额外的软件代价比较大的特点,基于多符号检测(MSD)的PCM/FM信号软件化解调系统,研究了一种基于MSD的迟早门载波同步和升降频码同步方法。利用MSD自身的优势,就地取材,简单地对本地时延和频偏进行加减即可达到同步要求。详细研究了低信噪比环境下,可变步长的时频同步方法,仿真了几种指标之间的关系。在系统代价较低的情况下保证了同步的快速实现。
Most synchronization methods of PCM/FM system need to add additional software in the receiver,the cost becomes higher.Aiming at this char acteristic,in the PCM/FM signal demodulation system based on MSD,an early-late gate carrier synchronization and lift frequency code synchronization method base d on MSD is studied.By utilizing the advantages of MSD,the synchronization requi rement can be achieved by adding and subtracting local time delay and doppler fr equency shift.A variable-step time-frequency synchronization method is studied en detail in the low SNR environment,and the relationship between several speci fications is simulated.This method ensures rapid implementation of synchronizati on with low system cost and it has some engineering application value.
出处
《无线电工程》
2012年第11期26-28,共3页
Radio Engineering
关键词
PCM
FM
MSD
迟早门
升降频
同步
PCM/FM
MSD
early-late gate
lift frequency
synchronization
