A novel generalized demodulation approach for multi-component signals

摘要

The generalized demodulation method based on maximal overlap discrete wavelet packet transform (MODWPT) is well suitable for separating multi-component signals due to the properties of MODWPT such as decomposing a signal into a sum of components and the same time-resolution in all decomposition layers. However, the related separation-method research meets lots of challenges because of multi-component signals whose components are overlapped in frequency at some instants. In this paper, a novel generalized demodulation approach is proposed to separate each component from the multi-component signals. A generalized short time Fourier transform (GSTFT) is introduced to project the multi-component analytic signal onto the time-frequency plane and a varying window function is used to improve the time-frequency concentration of GSTFT. The time-frequency plane is considered as a 2-D time-frequency image, the singular value decomposition (SVD) and the generalized demodulation technique are applied to obtain the component of interest. Simulation results show that after using the proposed approach, the time domain waveform and the instantaneous frequency of each component are obtained by analyzing multi-component signals whose components may be well separated in frequency at one instant and overlapped at a later instant.