Design a Mealy sequential circuit which investigates an input sequence X and which will produce an output of Z = 1 for any input sequence ending in 0101 provided that the sequence 110 has never occurred.
Example:
X = 0 1 0 1 0 1 1 0 1 0 1
Z = 0 0 0 1 0 1 0 0 0 0 0
Notice that the circuit does not reset to the start state when an output of Z = 1 occurs. However, your circuit should have a start state and should be provided with a method for manually resetting the flip-flops to the start state. A minimum solution requires six states. Design your circuit using NAND gates, NOR gates, and three D flip-flops. Any solution which is minimal for your state assignment and uses eight 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 next state are correct for each input. Then, starting in the proper initial state, determine the output sequence for the following
input sequences:
(1) X = 0 1 0 1 0 0 0 1 0 1 1 0
(2) X = 1 0 1 0 1 0 1 1 0 1 0 1