Design a Mealy sequential circuit which investigates an input sequence X and will produce an output of Z=1 whenever the total number of 0s in the sequence is odd, provided that the sequence 01 has occurred at least once.

Example:

X=1 1 0 0 0 1 1 0 1 0

Z=0 0 0 0 0 1 1 0 0 1

A minimum solution requires five states. Design your circuit using NAND gates, NOR gates, and three D flip-flops. Your circuit should have a start state and should be provided with a method of manually resetting the flip-flops to the start state. Any solution which is minimal for your state assignment and which uses 11 or fewer gates and inverters is acceptable. (Assign 000 to the start state.)Test Procedure: First, check out your state table by starting in each state and making sure that the present output and the next state are correct for each input. Then, starting in the proper initial state, determine the output sequence for the fol-lowing input sequences:

(1) X=1 0 0 0 1 1 0 1 0 0 1

(2) X=0 0 0 0 1 0 1 0 0 0 1