(b) A sequential circuit based on D flip-flops with input X and output Z is given in Figure 3. BA AB CLK- DA Q-A X DB Q-B QA Q-B ID Figure 3 Write the functions for DA, DB and Z. (ii) Plot the next state maps. (iii) Tabulate the excitation table. (iv) Draw the state diagram. (v) Analyze and determine the function of this circuit. Z (14 Marks) (c) Briefly discuss spurious (or redundant) switching in digital systems and suggest a way to reduce the spurious switching. (3 Marks)