A novel method of local chirp-rate estimation of LFM chirp signals in the time-frequency domain

In the paper, novel dynamic representations of a complex signal in the time-frequency domain are introduced. The proposed approach is based on using the gradient of the short-time Fourier transform complex phase. A channelized instantaneous complex frequency (CICF) and a complex local group delay (CLGD) are included in the presented signal representations. An application of the newly-introduced distributions is demonstrated by a local chirp-rate estimation of linear frequency modulated chirp signals in the time-frequency domain.