14.12   (a) A Moore sequential circuit has one input (x) and one output (z).z = 1if and only if the most recent input was 1and it was preceded by exactly two o's.Derive a state table for the circuit.

(b) Repeat for a Mealy circuit, i.e., z = 1if and only if the most recent input is 1and it was preceded by exactly two o's. Derive a state table for the circuit.

14.13   (a) A Mealy sequential circuit has one input (x) and one output (z).z can be 1when the fourth, eighth, twelfth, etc.inputs are present, and z = 1 if and only if the most recent input combined with the preceding three inputs was not a valid BCD encoding for a decimal digit; otherwise, z = o. Assume the BCD digits are received most significant bit first. Derive a state table for the circuit. (Eight states are sufficient.)

(b)          Repeat for a Moore circuit, i.e., z = 1if and only if, after the fourth, eighth, twelfth, etc. inputs have been received, the previous four inputs were not avalid BCD digit. (Nine states are sufficient.)

(c)        Is it possible for a Moore circuit to generate the correct output while the fourth input bit is present rather than after it has been received? Explain your answer.