A new structure for narrow transition band, lowpass digital filter design

In this paper, a new class of lowpass linear phase FIR filters is introduced. It is shown that lowpass filters with narrow transition bands can be realized efficiently by a structured form composed mainly of a few small FIR filters. The modular structure is suited for an implementation by a fast short convolution algorithm or a few single-chip filter IC's. A design procedure is considered in some detail and illustrated by an example. The properties and performance of the filter are discussed by analysis as well as design results. A brief discussion on its implementations concludes the paper.