Estimation for Instantaneous Frequency Using a Combined Fractional Time-Frequency Representation

Jiaqiang LI  Ronghong JIN  JunPing GENG  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.1   pp.189-191
Publication Date: 2007/01/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.1.189
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Sensing
time-frequency representations,  short-time Fourier transform,  Wigner distribution,  instantaneous frequency,  

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In this letter, a combined method based on the fractional linear and the fractional bilinear time-frequency representations (TFRs) is proposed. The method combines the windowed fractional short-time Fourier transform with the fractional Wigner distribution (WD) to estimate the instantaneous frequency (IF) of signals in the appropriate fractional time-frequency domain. For a multi-component signal, the method can significantly eliminate the cross terms and improve the time-frequency resolution of the auto-terms. It is applied to the detection and parameter estimation of linear frequency modulated (LFM) signals. The computer simulations clearly demonstrate that the method is effective.