A low-power FIR filter using combined residue and radix-2 signed-digit representation

This paper presents a FIR filter combining residue (RNS) and radix-2 signed digit (SD) representation. RNS offers parallelization of the computations and SD carry-free additions. The moduli set {2ⁿ-1, 2ⁿ, 2ⁿ+1} is used reducing the complexity of the RNS arithmetic units. The evaluated filters have 8, 12 and 16 taps, binary word lengths between 16 and 64 bits, and have been synthesized using a UMC 0.13 μm CMOS cell library with 8 metal layers. Power, delay, and area comparisons are made with equivalent 2´s complement designs. The area-delay and area-delay-power products shows that reduction in both power and area at the same filter throughput can be expected.