Some remarks on regularized Shannon sampling formulas

Abstract The fast reconstruction of a bandlimited function from its sample data is an essential problem in signal processing. In this paper, we consider the widely used Gaussian regularized Shannon sampling formula in comparison to regularized Shannon sampling formulas employing alternative window functions, such as the $$\sinh $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>sinh</mml:mo> </mml:math> -type window function and the continuous Kaiser–Bessel window function. It is shown that the approximation errors of these regularized Shannon sampling formulas possess an exponential decay with respect to the truncation parameter. The main focus of this work is to address minor gaps in the preceding papers [13, 14] and rigorously prove assumptions that were previously based solely on numerical tests. In doing so, we demonstrate that the $$\sinh $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>sinh</mml:mo> </mml:math> -type regularized Shannon sampling formula has the same exponential decay as the continuous Kaiser–Bessel regularized Shannon sampling formula, but both have twice the exponential decay of the Gaussian regularized Shannon sampling formula. Additionally, numerical experiments illustrate the theoretical results.