presentation a new method of time-frequency representation based on the s transform

s is a time-frequency transform based on the concept of short-time fourier transform and wavelet transform. the main property of this transform that separate it from the discrete short-time fourier transform is variable frequency resolution. but in this transform the change of resolution of high frequencies to low frequencies is very high. so another transform as a modified s transform is introduced to adjust the parameters that control the rate of change in resolution. in this paper, we introduce a modified s transform (mst) and s transform, and then on the basis of the type of s transform we introduce proposed s transform (pst) with two new parameters and with calculate the length of the used window the dependence it to parameters of the proposed method, review and the influence of each parameter on the rate of change over time in the form of theory and the simulation window apply. finally, simulate suggests transform and its performance for different parameters for fmcw signal detection and examined the influence of each parameter on the simulation .we describe and show the transform is better than the previous transform.