Linear and quadratic methods for positive time-frequency distributions

نویسنده

  • James W. Pitton
چکیده

This paper presents a new foundation for positive time{ frequency distributions (TFDs). Based on an integral equation formulation of nonstationary systems, a positive TFD can be constructed from a decomposition of a signal over an orthonormal basis. This basis function de nition of a positive TFD is used to obtain a relationship between the Wigner distribution and the positive TFD. The results are then generalized to derive positive joint distributions over arbitrary variables, following the approach of Baraniuk and Jones [1]. This general theory provides a common foundation for the two approaches of computing time-frequency representations: those based on linear decompositions of the signal (e.g., best basis methods) and those based on a quadratic, or bilinear, functional of the signal (i.e., Cohen's bilinear class).

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تاریخ انتشار 1997