Design and implementation of narrow-band linear-phase FIR filters with piecewise polynomial impulse response
T. Saramäki, Sushmita Mitra · 2003
The transfer function of these filters is a parallel connection of several branches with transfer functions of the form G/sub l/(z/sup L/)F/sub l/(z), where the length of each F/sub l/(z) is L. It is shown that by properly selecting the F/sub l/(z)'s the overall impulse response can be divided into several blocks of L samples in such a manner that in each block the impulse response is a polynomial of a given degree. The degree is one less than the number of branches, whereas the overall length of the impulse response is N=ML, where M is the length of the G/sub l/(z)'s. Efficient implementation forms are proposed for the overall filter. Examples are included illustrating the efficiency of the proposed approach in implementing narrow-band linear-phase FIR filters.