Methods for fractional delay approximation

Fractional delay filters have been common devices in many digital systems. They are used for implementing discrete-time systems which include delays that are not multiples of the sampling period. In this paper ideal fractional delay transfer function is approximated using some generalization of Taylor expansion known as Hummel-Seebeck-Obreshkov (HSO) expansion. When HSO is applied to fractional delay it leads to rational approximation that is equivalent to Pade approximation. Numerical results show that the proposed approximations are efficient.