Digital Systems: Principles and Design

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Digital Systems

TABLE 15.7 Excitation table for the for the sequential circuit-4

Present state Excitation inputs D , (J, K) Present output state after the

X inputs but before the transition

(Q

1

, Q

2

) Input X = 0 Input X = 1 Input X = 0 Input X = 1

0, 0 0, (0, 0) 1, (0, 1) 0 0

0, 1 0, (0, 0) 1, (0, 1) 1 0

1, 0 0, (1, 0) 1, (1, 1) 1 1

1, 1 0, (1, 0) 0, (1, 1) 1 1

Step 4: Make transition table from the expressions for Y = F

o

(X, Q) and Q.

Table 15.8 gives the transition table made by using the equations (15.12) and (15.13)

and (15.14).

TABLE 15.8 Transition table for the sequential circuit-4

Present state Next state after transition (Q 1, Q 2) Outpu