Draw the circuit diagram for the twisted-tail (Johnson) counterconsisting of 4 flip-flops
(A, B, C, E) with the following excitation: DA = QE', DB =QA, DC = QB, DE = QC.
Assume the flip-flops are cleared initially.
1. Obtain the compete state diagram showing both used and unusedstates and transitions. It is a self-correcting design?
2. If the design is not self-correcting - modify it to obtain aself-correcting design. Show the work and draw the circuit diagram for the counter withself-correction.
3. Design the state decoder which provides a high logic level atonly one output at a time. Draw the circuit diagram for the decoder.