One method for FIR minimum-phase multiplier-free filter design based on cosine and RRS filters

This paper presents one simple method for direct multiplier-free narrowband minimum-phase FIR filter design. The design is based on the minimum-phase filter specification. The designed filter is a cascade of recursive running sum (RRS) filters and cosine filters. The sharpening technique is used to improve the magnitude characteristic of the designed filter. We apply different modified sharpening polynomials to RRS and cosine filters. As a result, we obtain a less complex design that meets the desired minimum-phase specification. The Rouche´s theorem is used to prove that a designed filter is a minimum phase.