共用反正切鉴别器的低复杂载波跟踪算法

A Low Complexity Carrier Tracking Algorithm Based on Sharing an Arctangent Discriminator

针对一般载波跟踪环锁定范围窄,资源消耗大的问题,提出了QPSK直接序列扩频系统共用反正切鉴别器的低复杂度的载波跟踪算法,该算法锁相环(PLL)和锁频环(FLL)联合工作,共用一个反正切函数单元,比传统载波跟踪方法节约一个反正切单元和将近一半的乘法器与加法器。利用System Generator搭建模块所进行的仿真结果表明:所设计的载波跟踪算法复杂度与运算量大为降低,在数据跳变的同时且多普勒频率变化为阶跃函数、斜坡函数的情况下能快速、准确跟踪载波。

Abstract： In order to solve the problems of narrow lock range and large resources expense in the carrier tracking loop,a low complexity carrier tracking algorithm, whieh adapted to QPSK-modulated direct-sequence spreadspectrum systems, was proposed in this paper, it＇s phase-locked loop （PLL） and frequency-locked loop （FLL） shared a same aretangent unit. The new carrier tracking method which combining PLL with FLL was verified in this paper. Simulation of the scheme with System Generator indicated that this method significantly reduced the complexity and computation burden whenever the Doppler frequency was of a step equation or a simple equation of time. The carrier could be tracked under various situation by using the new carrier tracking loop.