Abstract
Applications of the Fourier transform are confined to analyses of stationary signals whose properties do not evolve in time. For the analysis of non-stationary signals whose frequencies vary with time, time-frequency two-dimensional representations must be applied. Those are members of Cohen's class, RID(Reduced Interference Distribution)and Scalogram. In this paper, a unified framework of such representations is proposed. In the newly proposed approach, a smoothing function is introduced to provided to provide a continuous transition between spectrogram and scalograms via wigner distribution. Then comparisons among spectrograms, scalograms, obtained by smoothing function acting on Wigner distribution, and RID were made for both simulated and measured signals. As a result of analyses, it is made clear that a best description of non-stationary signals is given by the RID among them.
