Special discrete-time filters having fractional delay

A novel family of special discrete-time filters having fractional delay is proposed, where a fractional-sample delay (FSD) filter serves as a versatile building block from which all other special filters of the family are derived. The specific feature of these filters is that the fractional delay is a parameter which can be varied. An illustrative example shows the performance of a specimen filter whose coefficients are obtained from the impulse response of an FIR FSD filter using polynomial approximation. The application of this filter to simultaneous instantaneous frequency estimation and fractional delay of a complex FM signal is also presented. (C) 1998 Elsevier Science B.V. All rights reserved.