A Probabilistic Error Model and Framework for Approximate Booth Multipliers

Approximate computing is a paradigm for high performance and low power design by compromising computational accuracy. In this paper, the structure of an approximate modified radix-4 Booth multiplier is analyzed. A probabilistic error model is proposed to facilitate the evaluation of the approximate multiplier for errors from the approximate radix-4 Booth encoding, the approximate regular partial product array, and the approximate 4-2 compressor. The normalized mean error distances (NMEDs) of 8-bit and 16-bit approximate designs are found by utilizing the proposed model. The results from the error model and the corresponding analytical framework are close to those found by simulation, thus confirming the validity of the proposed approach.