On the independent significance of generalizations of the Wigner distribution function

The Wigner distribution function (WDF) is a significant time-frequency analysis tool in, e.g., the theory of optical coherence and signal processing. Recently, various generalizations of the WDF associated with linear canonical transforms have been proposed to improve and broaden its applications. It is useful to identify which of these novel distributions have independent significance for further investigation. We plot these distributions for a test signal using symbolic integration to find which distributions are linear coordinate transforms of the WDF or have unique features. Five distributions are determined to be linear coordinate transforms of the WDF. Two distributions show unique characteristics. We focus on the mathematical interpretation, properties, and possible applications of those two distributions. We demonstrate how one of them can be used in the analysis of partially coherent systems.