Title :
A new positive time-frequency distribution
Author :
Fonollosa, Javier R. ; Nikias, Chrysostomos L.
Author_Institution :
Dept. of Signal Theory & Commun., Univ. Politecnica de Catalunya, Barcelona, Spain
Abstract :
This article studies the formulation of new members of the Cohen-Posch (1985) class of positive time-frequency energy distributions. Members of this class are always positive functionals and satisfy the marginal constraints. Therefore, they can be properly interpreted as distributions. We considered the minimization of cross-entropy measures with respect to different priors or “a priori” distributions and the case of no prior or maximum entropy, and concluded with the necessity to introduce new marginal constraints. New mixed in time and frequency constraints are derived based on a “direction invariance” criterion on the time-frequency plane that are directly related to the Fractional Fourier Transform. The implications of this new constrains in the positive class are analyzed from an information theoretic perspective. We conclude that the new constraints provide enough information to fully determine the resulting distribution and thus, no “a priori” distribution is necessary
Keywords :
Fourier transforms; functional equations; maximum entropy methods; signal representation; statistical analysis; time-frequency analysis; cross-entropy measures minimisation; direction invariance; fractional Fourier transform; information theory; marginal constraints; maximum entropy distribution; positive functionals; positive time-frequency distribution; time-frequency constraints; time-frequency representation; Constraint theory; Entropy; Fourier transforms; Frequency estimation; Information analysis; Signal processing; Signal resolution; Spectrogram; Time factors; Time frequency analysis;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on
Conference_Location :
Adelaide, SA
Print_ISBN :
0-7803-1775-0
DOI :
10.1109/ICASSP.1994.389816