基于 HHT的P SK 信号载波频率估计改进方法研究

摘要

在非协作通信系统中，信号解调需要对载波频率进行估计。提出了一种结合信噪比估计的希尔伯特-黄变换（Hilbert-Huang transform，HHT）的载波频率估计方法，通过信噪比合理选择固有模态分量（ intrinsic mode function，IMF）对信号进行时域滤波，再求边际谱来估计载波频率，并与其他几种方法进行比较。仿真结果表明，在信噪比低于-5 dB时，文中提出的相位调制信号（ phase shift keying，PSK）载频估计方法，归一化均方根误差小于10-1，相对误差小于5％，优于其他方法。%In a non-cooperative communication system, it is necessary to estimate the carrier frequency for blind sig-nal demodulation.In combination with SNR estimation, this paper proposes a carrier frequency estimation method based on Hilbert-Huang transform, and compares it with several other methods.It chooses intrinsic mode function component properly for time domain filtering under SNR estimation, and then estimates carrier frequency by margin-al spectrum.The simulation results show that when the SNR is lower than -5 dB, the normalized root mean square error is less than 10-1 and relative error is less than 5%, which illustrates that the proposed method of PSK carrier frequency estimation works better than the others.