Design of constant-delay systems based on symmetry of time-domain response

A method for design of constant-delay systems based on symmetry of time-domain response is presented. The symmetry error is estimated by using the zero-phase sinc pulse as the model of input signal. The constant-delay systems are obtained by minimizing this error. The design method allows independent control of the system´s delay and the constant group delay bandwidth. Method´s features are illustrated by a family of the optimum all-pass and the corresponding low-pass systems. The systems are compared to classic constant-delay approximations.