A Modified S Transform with Adjustable Window Function

The window function of S transform has a linear relationship with frequency, and it is unable to balance the time resolution of the lower frequency regions with the frequency resolution of the higher frequency regions. A modified S transform is proposed in this paper to overcome the limitations. By establishing an arctangent relationship between frequency and the width of window, the width of the time domain window function can be adaptively changed with frequency within a certain range. This method takes into account the accuracy of time positioning at lower frequencies and the accuracy of frequency positioning at higher frequencies. The simulation results show that the proposed method has better energy aggregation and higher time-frequency resolution.