Estimating instantaneous frequency of multicomponent signal using optimization strategy in fractional domain

Abstract

AbstractEstimating instantaneous frequencies (IFs) overlapped in both time and frequency domains is an important issue in time‐frequency (TF) analysis. In this letter, the TF information of the signal in fractional domain is combined with an optimization strategy to estimate the IF of multicomponent overlapping signals. The method converts the IF estimation into the problem of function fitting in the two‐dimensional plane. First, based on the fractional window function with a specific angle, the energy of the multicomponent signal is concentrated around a certain signal component to obtain a relatively high‐resolution TF representation in fractional domain. Second, the training data set is constructed by the obtained TF representation, which will be used to estimate the IF. At last, the IF curve of the signal component is fitted with an optimization function. Numerical experiments verify the effectiveness of the proposed method under the low SNR.