EXP4 Decoder-Gray To Binary

This is a modification of the circuit Gray Code To Binary Converter. In this version only two-input XOR gates are used. Each of the binary input bits connect to one input of the XOR gates. The other input terminals of the XOR gates connect to the output of a succeeding XOR gate except for the gate that generates the most significant output bit. Instead, this fourth XOR gate serves as an MSB buffer. One input of this XOR gate is connected to ground (logic 0) so the output state simply follows the input.