Multiwindow time-varying spectrum with instantaneous bandwidth and frequency constraints

We build on Cohen's work on instantaneous bandwidth and frequency by extend ing it to a multiwindow framework for polynomial phase signals. Unlike the case with a single spectrogram, which Cohen considered, our multiwindow fra mework allows one to obtain a time-varying spectral estimate that simultane ously satisfies instantaneous bandwidth and frequency constraints. We then develop a method utilizing this new multiwindow time-varying spectral techn ique for estimating the instantaneous frequency of a signal. The method is computationally simple, asymptotically unbiased for noise-free signals, and provides a signal-to-noise ratio (SNR) improvement of more than 3 dB over other estimators, including the cross-polynomial Wigner distribution method , for quadratic and cubic FM signals.