Prerequisite – Number System and base conversions. Excess-3 binary code is a unweighted self-complementary BCD code. Self-Complementary property. Bcd to excess 3 code converter 1. BCD to EXCESS 3 Code Converter By Ushaswini chowdary.M 2. Introduction • The availability of large variety of codes for the same discrete elements of information results in the use of different codes by the different systems.
Design a BCD to excess 3 code converter using minimum number of NAND gates. Hint: use k map techniques. Firstly we make the truth table: BCD no A B C D EXCESS-3 NO W X Y Z 0 0 0 0 0 0 1 1 0 0 0 1 0 1 0 0 0 0 1 0 0 1 0 1 0 0 1 1 0 1 1 0 0 1 0 0 0 1 1 1 0 1 0 1 1 0 0 0 0 1 1 0 1 0 0 1 0 1 1 1 1 0 1 0 1 0 0 0 1 0 1 1 1 0 0 1 1 1 0 0 After that by using K maps we can get simplified functions for w, x, y, z shown below as: NAND gate implementation for simplified function W = BD + AD + AB' + BC Through complementing twice we find W = ((BD + AD + AB' + BC)')' = ((BD)'. (BC)')' X = BC'D + B'D + B'C Through complementing twice we find X = BC'D + B'D + B'C = ((BC'D)'. (B'C)')' Y = C'D' + CD = ((C'D')' + (CD)')' Z = D' Logic diagram for BCD to excess 3 code converter using minimum number of NAND gates.