高动态微弱信标信号载波捕获跟踪的设计与实现

摘要

To capture and track the signal’s carrier in high dynamic and low signal⁃to⁃noise ratio(SNR)environment,the schemes of frequency locked loop(FLL)with two factorials add phase locked loop(PLL)with three factorials are proposed in this article. To solve the low SNR problem,the frequency discrimination method based on periodogram is used in FLL to realize signal’s carrier capture under very low SNR. The three⁃order PLL is monitored by the input control signal of the voltage con⁃trolled oscillator(VCO)to adjust the band width of loop filter self⁃adaptively,so as to meet the requirement of large dynamic range of signal carrier frequency in high dynamic state. The proposed scheme was verified on a signal processing board with FPGAs. The experimental results are presented at last.%为了研究高动态低信噪比下信标信号的载波捕获跟踪问题，采用两级二阶锁频环（FLL）和一级三阶锁相环（PLL）技术方案。FLL采用基于周期图的鉴频方法，实现极低信噪比下信号载波的捕获。PLL中的三阶锁相环通过对环路压控振荡器（VCO）的输入控制信号进行监测，自适应地调整环路滤波器的带宽，以满足高动态下信号载波频率动态范围大的要求。在基于FPGA构建的信号处理板上验证了上述实现方案，并给出实验结果。