1.14 A sequential circuit has one input (X) and two outputs (D and B). X represents a 4-bit binary number N, which is input least significant bit first. D represents a 4-bit binary number equal to N - 2, which is output least significant bit first. At the time the fourth input occurs, B = 1 if N-2 is negative; otherwise, B = 0. The circuit always resets after the fourth bit of X is received. (a) Derive a Mealy state graph and table with a minimum number of states (six states). (b) Try to choose a good state assignment. Realize the circuit using J-K flip-flops and NAND gates. Repeat using NOR gates. (Work this part by hand.) (e) Check your answer to (b) using the Logic Aid program. Also use the program to find the NAND solution for two other state assignments