基于叉积鉴频器的π/4-QPSK信号数字化解调  

Digital Demodulation of π/4-QPSK Signal Based on Cross Product Frequency Discriminator

作　　者：周凡[1] 郑林华[1] 陶文祥[1] 

机构地区：[1]国防科技大学电子科学与工程学院,长沙410073

出　　处：《遥测遥控》2017年第2期49-55,共7页Journal of Telemetry,Tracking and Command

基　　金：基金项目:国防关键技术攻关

摘　　要：π/4-QPSK差分解调方式在快衰落瑞利移动信道下,具有较相干检测更优的性能,且解调速度快。但是,在突发通信中有时却存在相当大的载波频偏,导致接收机不能正常工作。如果能采用叉积鉴频法对大频偏进行有效校正,则可将载波残差控制在允许的范围内,从而提高接收系统的非相干解调性能。仿真结果表明,基于叉积鉴频器的π/4-QPSK信号数字化差分解调方法可在大频偏突发通信中取得良好的解调性能。π/4-QPSK differential demodulation has better performance than coherent detection and has fast demodulation speed in the fast fading Rayleigh channel. However, there is a large carrier frequency offset in the burst communication, which causes the receiver to work abnomally. Using the cross-product frequency discrimination method to effectively modify the large frequency offset, the residual carrier frequency offset can be controlled within the allowable range, so the incoherent demodulation performance of the receiving system is improved. The simulation results show that the digital differential demodulation method of π/4-QPSK signal based on cross product frequency discriminator can obtain good demodulation performance in large frequency offset burst communication.

关 键 词：Π/4-QPSK 载频估计 载波频偏 

分 类 号：TN941.4[电子电信—信号与信息处理]