On Gabor frames generated by B-splines, totally positive functions, and Hermite functions

Abstract

The frame set of a window $\phi\in L^2(\mathbb{R})$ is the subset of all lattice parameters $(\alpha, \beta)\in \mathbb{R}^2_+$ such that $\mathcal{G}(\phi,\alpha,\beta)=\{e^{2\pi i\beta m\cdot}\phi(\cdot-\alpha k) : k, m\in\mathbb{Z}\}$ forms a frame for $L^2(\mathbb{R})$. In this paper, we investigate the frame set of B-splines, totally positive functions, and Hermite functions. We derive a sufficient condition for Gabor frames using the connection between sampling theory in shift-invariant spaces and Gabor analysis. As a consequence, we obtain a new frame region belonging to the frame set of B-splines and Hermite functions. For a class of functions that includes certain totally positive functions, we prove that for any choice of lattice parameters $\alpha, \beta>0$ with $\alpha\beta<1,$ there exists a $\gamma>0$ depending on $\alpha\beta$ such that $\mathcal{G}(\phi(\gamma\cdot),\alpha,\beta)$ forms a frame for $L^2(\mathbb{R})$.