A simple design of FIR filters with powers-of-two coefficients

A design algorithm for finite-impulse response (FIR) filters with powers-of-two coefficients (2PFIR filters) is presented. The algorithm enables the design of 2PFIR filters with sharp cutoff. The 2PFIR filters are attractive for high-speed operation and simplification of hardware. However, the optimal or suboptimal design of 2PFIR filters with sharp cutoff have been difficult in the minimax sense. The algorithm proposed is composed of two methods. The first is suboptimal design, which preserves a proportional relation between the coefficients of the conventional FIR filters and the 2PFIR filters. This method is referred to as the proportional relation-preserve (PRP) method. The second is the application of the simple symmetric-sharpening (SSS) method. The SSS method is applied when the PRP method cannot realize the given filter specifications. Using the PRP and SSS methods, the 2PFIR with filter length N>200 can be easily designed