Consider the following circuit. The flip-flops are positive edge triggered D…
2005
Consider the following circuit.
The flip-flops are positive edge triggered D FFs. Each state is designated as a two bit string Q0Q1. Let the initial state be 00. The state transition sequence is:
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Key equations: From the circuit, the left flip-flop input is the complement of Q0, so D0 = Q0'. The right flip-flop input implements Q0 XNOR Q1, so D1 = Q0 XNOR Q1.
Current = 00: D0 = 1, D1 = 1 (because 0 XNOR 0 = 1) -> Next = 11
Current = 11: D0 = 0, D1 = 1 (because 1 XNOR 1 = 1) -> Next = 01
Current = 01: D0 = 1, D1 = 0 (because 0 XNOR 1 = 0) -> Next = 10
Current = 10: D0 = 0, D1 = 0 (because 1 XNOR 0 = 0) -> Next = 00
Therefore, starting from 00 the state sequence is 00 -> 11 -> 01 -> 10 -> 00 and it repeats. The option that lists these states in this order is the correct answer.
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