Short-time Fourier transform and superoscillations

Fuente: arXiv
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Autori principali: Alpay, Daniel, De Martino, Antonino, Diki, Kamal, Struppa, Daniele C.
Natura: Preprint
Pubblicazione: 2024
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author Alpay, Daniel
De Martino, Antonino
Diki, Kamal
Struppa, Daniele C.
author_facet Alpay, Daniel
De Martino, Antonino
Diki, Kamal
Struppa, Daniele C.
contents In this paper we investigate new results on the theory of superoscillations using time-frequency analysis tools and techniques such as the short-time Fourier transform (STFT) and the Zak transform. We start by studying how the short-time Fourier transform acts on superoscillation sequences. We then apply the supershift property to prove that the short-time Fourier transform preserves the superoscillatory behavior by taking the limit. It turns out that these computations lead to interesting connections with various features of time-frequency analysis such as Gabor spaces, Gabor kernels, Gabor frames, 2D-complex Hermite polynomials, and polyanalytic functions. We treat different cases depending on the choice of the window function moving from the general case to more specific cases involving the Gaussian and the Hermite windows. We consider also an evolution problem with an initial datum given by superoscillation multiplied by the time-frequency shifts of a generic window function. Finally, we compute the action of STFT on the approximating sequences with a given Hermite window.
format Preprint
id arxiv_https___arxiv_org_abs_2407_12502
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Short-time Fourier transform and superoscillations
Alpay, Daniel
De Martino, Antonino
Diki, Kamal
Struppa, Daniele C.
Functional Analysis
In this paper we investigate new results on the theory of superoscillations using time-frequency analysis tools and techniques such as the short-time Fourier transform (STFT) and the Zak transform. We start by studying how the short-time Fourier transform acts on superoscillation sequences. We then apply the supershift property to prove that the short-time Fourier transform preserves the superoscillatory behavior by taking the limit. It turns out that these computations lead to interesting connections with various features of time-frequency analysis such as Gabor spaces, Gabor kernels, Gabor frames, 2D-complex Hermite polynomials, and polyanalytic functions. We treat different cases depending on the choice of the window function moving from the general case to more specific cases involving the Gaussian and the Hermite windows. We consider also an evolution problem with an initial datum given by superoscillation multiplied by the time-frequency shifts of a generic window function. Finally, we compute the action of STFT on the approximating sequences with a given Hermite window.
title Short-time Fourier transform and superoscillations
topic Functional Analysis
url https://arxiv.org/abs/2407.12502