55 / 2017-06-09 16:15:46

Adaptive short-time fractional Fourier transform used in time-frequency analysis

14631,14632,14633,14634

In order to improve the time-frequency resolutions of short-time fractional Fourier transform, adaptive short-time fractional Fourier transform (ASTFRFT) method is used in this paper. The optimal order of ASTFRFT is given by maximizing kurtosis of signal in fractional domain, the window width of ASTFRFT is searched by the maximal Shannon entropy of time-frequency distribution. Short-time fractional Fourier transform has lots of transform orders, its window width has several options, ASTFRFT selects its fractional transform order by kurtosis, and selects its width window by Shannon entropy of time-frequency distribution, for non-stationary signals, The experiment results reveal that the ASTFRFT has better effect than the short-time fractional Fourier transform with arbitrary fractional order, the ASTFRFT has better effect than short-time fractional Fourier transform with arbitrary window width. For multi-components signals, ASTFRFT can solve the the problem of selecting the optimal order and suitable window width for short-time fractional Fourier transform, and it can give good time-frequency resolutions.