针对低载噪比条件下高动态信标信号的频率跟踪,分析了传统锁频环的性能及其在低载噪比下的应用局限,进一步给出了基于快速傅里叶变换(FFT,Fast Fourier Transform)鉴频的二阶锁频环设计方法,实现了低载噪比下的载频快速捕获与跟踪。计算机仿真结果表明,输入载噪比为35 dB/Hz、采样率为4 MHz的条件下,基于FFT鉴频的锁频环对高动态信标信号的捕获时间小于0.2秒。 Aiming at the frequency tracking of high dynamic beacon signal with low carrier-to-noise ratio (SNR), the performance of the traditional frequency-locked loop and its application in low carrier-to-noise ratio are analyzed. The fast Fourier transform Fourier Transform) second-order frequency-locked loop design method to achieve fast carrier-frequency acquisition and tracking under low carrier-to-noise ratio. Computer simulation results show that the locking frequency of the frequency-locked loop based on FFT is less than 0.2 second when the input carrier-to-noise ratio is 35 dB / Hz and the sampling rate is 4 MHz.