New method for instantaneous frequency estimations of LFM signals
一种新的线性调频信号的瞬时频率估计方法*

According to the fact that Hilbert-Huang transformation(HHT) is a main component analysis method and that linear frequency modulation(LFM) signals instantaneous frequencies are lines with respect to variation time.This paper combined the HHT and least squares method to implement their instantaneous frequency estimations.Moreover only used the middle of instantaneous time-frequency samples obtained by HHT to fit instantaneous frequency line,which not only could reduce the influence of the end effects inherent in HHT on instantaneous frequency estimation more simply and efficiently than that changing the HHT algorithm did,but also the much more precision instantaneous parameter estimations could be directly achieved.Simulation results show that the proposed method has many advantages over the wavelet ridge method in term of instantaneous frequency estimation of LFM signals.