Abstract
In this note we consider continuous-time Weyl-Heisenberg (Gabor) frame expansions with rational oversampling. We present a necessary and sufficient condition on a compactly supported function g(t) generating a Weyl-Heisenberg frame for L2 (ℝ) for its minimal dual (Wexler-Razdual) γ0 (t) to be compactly supported. We furthermore provide a necessary and sufficient condition for a band-limited function g(t) generating a Weyl-Heisenberg frame for L2 (ℝ) to have a band-limited minimal dual γ0 (t). As a consequence of these conditions, we show that in the cases of integer oversampling and critical sampling a compactly supported (band-limited) g(t) has a compactly supported (band-limited) minimal dual γ0(t) if and only if the Weyl-Heisenberg frame operator is a multiplication operator in the time (frequency) domain. Our proofs rely on the Zak transform, on the Zibulski-Zeevi representation of the Weyl-Heisenberg frame operator, and on the theory of polynomial matrices.
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Communicated by Akram Aldroubi
on leave from Department of Communications, Vienna University of Technology
This work was supported in part by FWF grants P10531-ÖPH, P12228-TEC, and J1629-TEC.
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Bölcskei, H. A necessary and sufficient condition for dual Weyl-Heisenberg frames to be compactly supported. The Journal of Fourier Analysis and Applications 5, 409–419 (1999). https://doi.org/10.1007/BF01261635
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DOI: https://doi.org/10.1007/BF01261635