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The presence of cross terms in spectrograms, a bilinear transform, is studied via the ambiguity function interpretation. Proof is shown that such interference occurs between signal components either in a dominant, subdued or rejected state. Experimental results are also given to demonstrate the interdependencies between the signal structure, window and cross terms in the spectrogram.

The development of unified recursive algorithms for data shuffling purposes in signal processing applications is presented. Designed for data sequence shuffling in bit reversed, Gray code and bit reversed Gray code, the new algorithms are able to compute the permutation index from only one logical or arithmetic operation. They may also be applied to the fast Fourier transform, the fast Hartley transform and mutual conversion within the Walsh-, Paley- and Hadamard-ordered Walsh transforms.

A new class of time-frequency distributions is presented. Other time-frequency representations (TFR) have many limitations, and the Choi-Williams distribution is considered the best so far. But it does not completely meet the support properties in time and frequency. Results show that the new TFR, called the reduced interference distribution (RID), provides a high-resolution, readable localization of the signal energy spectrum in the time-frequency plane. A systematic procedure to create RID kernels is proposed, and some aspects, properties and limitations of the new distribution are discussed.