基于System Generator的QPSK数字调制器设计

载波同步是相干解调通信系统中必不可少的组成部分,常用锁相环技术予以实现。System Generator是一款理想的FPGA开发软件,它提供了FPGA和simulink仿真软件的接口,可以把simulink中的模型自动转换成位流文件,以便下载到FPGA中,实现FPGA硬件设计的自动化。采用数字锁相环技术,在simulink中利用System Generator建立QPSK调制系统的模型,并仿真以验证锁相环技术的性能。仿真结果表明,通过合理设置参数,数字锁相环能很好地获取同频同相的载波分量,实现通信系统的正确解调。

The Simulation of QPSK Coherent Demodulation Based on the System Generator Modeling

Carrier synchronization technique is an essential component in coherent demodulation communication systems,which are typically implemented by PLL（Phase-Locked Loop）.System Generator is an ideal FPGA development software,which provides interface for FPGA and simulink.The model can be automatically converted to bit-stream file in System Generator in order to download to FPGA,achieving the FPGA hardware design automation.In this paper,digital PLL technology is used to model a QPSK modulation system in simulink by System Generator and verify the PLL performance through the simulation.The results show that,digital PLL is an excellent technique to generate the local carrier with identical frequency and phase,and demodulate receiving signals correctly by setting reasonable parameters.