National Natural Science Foundation of China (No.51375152, No.51505002);Program of Natural Science Foundation for Colleges and Universities in Anhui Province (No.KJ2015A080)
The existing methods for analyzing non-stationary signal all have different defects.The time-frequency resolution of short-time Fourier transform is limited by the uncertainty principle.The boundary effect and mode mixing of Hilbert-Huang transform often result in an unclear time-frequency distribution.Analytical mode decomposition is only suitable for analyzing multi-component signal with constant frequencies.For the multi-component signal with time-varying frequencies
especially when the spectrum overlaps
a method termed generalized analytical mode decomposition (GAMD) is proposed for analyzing these signals.In GAMD
generalized Fourier transform is used to convert the time-varying frequencies to constant ones without overlapping in spectrum and then the analytical mode decomposition is adopted to handle the transformed signal.Lastly
the inverse generalized Fourier transform is used to demodulate the obtained mono-components.Hence
GAMD is very suitable for analyzing time-varying non-stationary signals.The proposed GAMD method is compared with short-time Fourier transform and Hilbert-Huang transform through analyzing simulation signals and the results indicate that GAMD possesses more accurate decomposing results and higher time-frequency resolution.