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arXiv · 1104.4894

Gabor Frames and Totally Positive Functions

Karlheinz Gröchenig·Joachim Stöckler
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Abstract

Let $g$ be a totally positive function of finite type. Then the Gabor set $\{e^{2\pi i \beta l t} g(t-\alpha k), k,l \in Z \}$ is a frame for $L^2(R)$, if and only if $\alpha \beta <1$. This result is a first positive contribution to a conjecture of I.\ Daubechies from 1990. So far the complete characterization of lattice parameters $\alpha, \beta $ that generate a frame has been known for only six window functions $g$. Our main result now provides an uncountable class of functions. As a byproduct of the proof method we derive new sampling theorems in shift-invariant spaces and obtain the correct Nyquist rate.

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Karlheinz Gröchenig, Joachim Stöckler. 2011-04-26. Gabor Frames and Totally Positive Functions. https://doi.org/10.1215/00127094-2141944

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