π/4DQPSK载波跟踪环的设计与实现

Design and Realization of π/4DQPSK Carrier Tracking Loop

简单介绍了无线通信技术中π/4DQPSK技术的特点和存在的主要问题,给出了其调制原理。针对在接收机解调时存在的载波频率偏移的问题,设计了一种完整的载波跟踪方案,详细推导了方案中鉴别器的算法,给出了二阶环路滤波器和数控振荡器(NCO)的实现方案,并在Matlab工具中完成了方案的算法仿真和现场可编程门阵列(FPGA)测试。结果证明该方案设计简单,有良好的抗噪声性能,能有效的实现载波跟踪。

This paper simply describes the π/4DQPSK technology and the modulation theory.To solve the problem of carrier frequency offset,a complete solution for carrier tracking is designed,the in-detail derivation of discriminator and the realization of loop filter and numerical controlled oscillator（nco） are given.The algorithm simulation of the scheme with Matlab and the FPGA test indicate that this solution is simple,feasible,anti-noise,and effective for carrier tracking.