November 9, 2004

Speaker: Götz Pfander
School of Engineering and Science
International University Bremen
Germany

Title: Sampling and identification of operators with bandlimited or periodic Kohn-Nirenberg symbols

Joint work with Werner Kozek and David Walnut.

 Abstract:

Identification of incompletely known linear operators based on the observation of one input and corresponding output signal is a common goal in communications engineering (channel sounding) and other applied sciences.

We shall give sufficient and necessary conditions for the identifiability of operator classes which are characterized by a bandlimitation (slowly time-varying channels) or a periodicity condition (periodically time varying systems) on the respective Kohn-Nirenberg symbols. We shall discuss connections to the uncertainty principle and "minimal rectangles in phase space" as described by Folland, and to the work of Kailath and Bello.

In detail, we shall discuss classes of underspread or overspread operators, of Gabor frame operators and of Gabor multipliers.

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