VARIABLE TAYLOR REALIZATION AND IMPROVED APPROXIMATION OF FIR FRACTIONAL DELAY SYSTEMS

A modular realization, based on the Taylor structure, is proposed for maximally hat fractional delay FIR systems. The realization enjoys ind ependence of the multiplier coefficients to changes of the system orde r, availability of closed-form formulas and recurrence for the multipl ier coefficients, requirement of one less multiplier coefficient compa red to the direct-form realizations, and existence of schemes for effi cient variable delay and order implementations. It is shown that for a variable delay structure, the coefficient updating operation can be p erformed efficiently using a simple recurrence, and the transient effe cts can be mitigated to at most two samples. A modified form of the st ructure with enhanced modularity is also proposed for odd-order system s. Two variable delay schemes are proposed for this modified structure : A transient-free scheme and a scheme to gradually improve the approx imations during the transient phase. A method is also proposed for imp roved approximation under a fixed total number of variable multiplier coefficients. (C) 1998 John Wiley & Sons, Ltd.