A modified truncation and rounding-based scalable approximate multiplier with minimum error measurement

Abstract

Multiplication necessitates more hardware resources and processing time. In a scalable method of approximate multiplier, the truncated rounding technique is added to reduce the number of logic gates in partial products with the help of leading one-bit architecture. Truncation and Rounding based Scalable Approximate Multiplier (TOSAM) has few modes of error measurement based upon height (h) and truncated (t) named as (h,t). These multipliers are named as TOSAM(0,2), TOSAM(0,3), TOSAM(1,5), TOSAM(2,6), TOSAM(3,7), TOSAM(4,8), and TOSAM(5,9). Multiplication provides a substantial impact on metrics like power dissipation, speed, size and power consumption. A modified approximate absolute unit is proposed to enhance the performance of the existing approximate multiplier. The existing 16-bit (3,7) error measurement multiplier shows an error measurement value of 0.4 %. The proposed 16-bit multiplier for the same error measurement possesses the error measured value is of 0.01%, mean relative error measured value of 0.3 %, mean absolute relative error measured value of 1.05, normalized error distance measured value of 0.0027, variance of absolute error measured value of 0.52, delay of 1.87 ns, power of 0.23 mW, energy of 0.4 pJ. The proposed multiplier can be applied in image processing. The work is designed in Verilog HDL and simulated in Modelsim, Synthesized in Vivado.