Time-frequency Representations of Wigner Type and Pseudo-differential Operators

We introduce a τ -dependent Wigner representation, Wigτ , τ ∈ [0, 1], which permits us to define a general theory connecting time-frequency representations on one side and pseudo-differential operators on the other. The scheme includes various types of time-frequency representations, among the others the classical Wigner and Rihaczek representations and the most common classes of pseudo-differential operators. We show further that the integral over τ of Wigτ yields a new representation Q possessing features in signal analysis which considerably improve those of the Wigner representation, especially for what concerns the so-called “ghost frequencies”. The relations of all these representations with respect to the generalized spectrogram and the Cohen class are then studied. Furthermore, a characterization of the Lp-boundedness of both τ -pseudo-differential operators and τ -Wigner representations are obtained.