Wigner measures in the discrete setting: high-frequency analysis of sampling & reconstruction operators

The goal of this article is that of understanding how the oscillation and concentration effects developed by a sequence of functions in ${\mathbb{R}}^d$ are modified by the action of Sampling and Reconstruction operators on regular grids. Our analysis is performed in terms of Wigner and defect measures, which provide a quantitative description of the high frequency behavior of bounded sequences in $L^2(mathbb{R}^d)$. We actually present explicit formulas that make possible to compute such measures for sampled/reconstructed sequences. As a consequence, we are able to characterize sampling and reconstruction operators that preserve or filter the high-frequency behavior of specific classes of sequences. The proofs of our results rely on the construction and manipulation of Wigner measures associated to sequences of discrete functions.