Mechanism of the cross-terms in spectrograms

Using the ambiguity domain interpretation, the authors explore the mechanism of the cross-terms (or interferences) in spectrograms. They emphasize that the spectrogram does, in general, have cross-terms. Depending on the signal structure and the window used, the cross-terms may sometimes be conspicuous, reduced, or completely eliminated. The cross-term suppression in spectrograms is governed by the signal-theoretic version of the uncertainty principle. Some experimental results are provided to illustrate the cross-term mechanism in spectrograms