Which of the following count sequence can not be generated using 3 bit JK flip-flops?
(A) 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 0, 0, 0, …
(B) 1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, …
(C) 0, 4, 6, 7, 3, 2, 0, 0, 4, 6, 7, 3, 2, 0, …
(D) None of above


Answer: (A)

Explanation: Sequences 1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, … and 0, 4, 6, 7, 3, 2, 0, 0, 4, 6, 7, 3, 2, 0, … has less than 8 unique states, so we can generate these sequence count using only 3 flip-flops.
But, for count sequence 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 0, 0, 0, …, there are 12 states, so we need more than 3 flip-flops.

So, option (A) is correct.


Quiz of this Question