Using new designed NLG gate for the realization of four-bit reversible numerical comparator

The reversible gates, attracting people´s attention increasingly, have been widely used in low-power CMOS design, optical computing and quantum computing. This paper introduces one 2*2 reversible gate named NLG gate, then designs a novel four-bit reversible numerical comparator circuit based on it. The character of NLG gate is that only when both of the inputs are the same, the value of the second output is 1. Since the proposed work is explored for the first time ever in literature, the contribution of this paper will create a new thread of research in the area of reversible logic circuit.