  In error-tolerant applications, approximate adders have been exploited
extensively to achieve energy efficient system designs. Mean error distance is
one of the important error metrics used as a performance measure of approximate
adders. In this work, a fast and efficient methodology is proposed to determine
the exact mean error distance in approximate lower significant bit adders. A
detailed description of the proposed algorithm along with an example has been
demonstrated in this paper. Experimental analysis shows that the proposed
method performs better than existing Monte Carlo simulation approach both in
terms of accuracy and execution time.
