On the Behavior of the Threshold Operator for Bandlimited Functions

One interesting question is how the good local approximation behavior of the Shannon sampling series for the Paley–Wiener space PW[1 over π] is affected if the samples are disturbed by the non-linear threshold operator. This operator, which is important in many applications, sets all samples whose a...

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Main Authors: Boche, Holger, Monich, Ullrich
Other Authors: Massachusetts Institute of Technology. Research Laboratory of Electronics
Format: Article
Language:en_US
Published: Springer-Verlag 2014
Online Access:http://hdl.handle.net/1721.1/85974
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author Boche, Holger
Monich, Ullrich
author2 Massachusetts Institute of Technology. Research Laboratory of Electronics
author_facet Massachusetts Institute of Technology. Research Laboratory of Electronics
Boche, Holger
Monich, Ullrich
author_sort Boche, Holger
collection MIT
description One interesting question is how the good local approximation behavior of the Shannon sampling series for the Paley–Wiener space PW[1 over π] is affected if the samples are disturbed by the non-linear threshold operator. This operator, which is important in many applications, sets all samples whose absolute value is smaller than some threshold to zero. In this paper we analyze a generalization of this problem, in which not the Shannon sampling series is disturbed by the threshold operator but a more general system approximation process, were a stable linear time-invariant system is involved. We completely characterize the stable linear time-invariant systems that, for some functions in PW[1 over π], lead to a diverging approximation process as the threshold is decreased to zero. Further, we show that if there exists one such function then the set of functions for which divergence occurs is in fact a residual set. We study the pointwise behavior as well as the behavior of the L[superscript ∞]-norm of the approximation process. It is known that oversampling does not lead to stable approximation processes in the presence of thresholding. An interesting open problem is the characterization of the systems that can be stably approximated with oversampling.
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spelling mit-1721.1/859742022-10-02T00:59:32Z On the Behavior of the Threshold Operator for Bandlimited Functions Boche, Holger Monich, Ullrich Massachusetts Institute of Technology. Research Laboratory of Electronics Monich, Ullrich Monich, Ullrich One interesting question is how the good local approximation behavior of the Shannon sampling series for the Paley–Wiener space PW[1 over π] is affected if the samples are disturbed by the non-linear threshold operator. This operator, which is important in many applications, sets all samples whose absolute value is smaller than some threshold to zero. In this paper we analyze a generalization of this problem, in which not the Shannon sampling series is disturbed by the threshold operator but a more general system approximation process, were a stable linear time-invariant system is involved. We completely characterize the stable linear time-invariant systems that, for some functions in PW[1 over π], lead to a diverging approximation process as the threshold is decreased to zero. Further, we show that if there exists one such function then the set of functions for which divergence occurs is in fact a residual set. We study the pointwise behavior as well as the behavior of the L[superscript ∞]-norm of the approximation process. It is known that oversampling does not lead to stable approximation processes in the presence of thresholding. An interesting open problem is the characterization of the systems that can be stably approximated with oversampling. 2014-03-28T19:44:56Z 2014-03-28T19:44:56Z 2013-01 2012-11 Article http://purl.org/eprint/type/JournalArticle 1069-5869 1531-5851 http://hdl.handle.net/1721.1/85974 Boche, Holger, and Ullrich J. Mönich. “On the Behavior of the Threshold Operator for Bandlimited Functions.” J Fourier Anal Appl 19, no. 1 (February 2013): 1–19. en_US http://dx.doi.org/10.1007/s00041-012-9254-1 Journal of Fourier Analysis and Applications Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Springer-Verlag Monich
spellingShingle Boche, Holger
Monich, Ullrich
On the Behavior of the Threshold Operator for Bandlimited Functions
title On the Behavior of the Threshold Operator for Bandlimited Functions
title_full On the Behavior of the Threshold Operator for Bandlimited Functions
title_fullStr On the Behavior of the Threshold Operator for Bandlimited Functions
title_full_unstemmed On the Behavior of the Threshold Operator for Bandlimited Functions
title_short On the Behavior of the Threshold Operator for Bandlimited Functions
title_sort on the behavior of the threshold operator for bandlimited functions
url http://hdl.handle.net/1721.1/85974
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