Coefficient optimization for area-effective multiplier-less FIR filters

This paper presents the systematic synthesis of multiplier-less FIR filters with a novel complexity-aware quantization algorithm. Both signed-digit representations and common subexpression elimination (CSE) are investigated to reduce the computational complexity at the bit level. For comparable filter responses, the simulation shows that our approach requires only half (49.06%∼ 50.94%) additions of the straightforward quantized filters. Both with CSE, our FIR synthesizer has comparable results with the CSD-encoded coefficients, which have the theoretically minimum non-zero terms. Moreover, our approach outperforms CSD in most cases because of the direct control over additions and the zero-overhead insertion of non-zero terms.