Exam-style question
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A Mealy machine starts in state S. Its transition table is: from S, input 0 leads to T and produces output 1; from S, input 1 leads to S and produces output 0; from T, input 0 leads to S and produces output 0; from T, input 1 leads to T and produces output 1. Trace the input sequence 0110. State the sequence of states visited after each input and the output sequence.
Model answer
What a good answer should say
- The machine starts in S.
- Input 0 takes S to T and produces 1.
- Input 1 takes T to T and produces 1.
- Input 0 takes T to S and produces 0.
Explanation
Why this works
The current state must be used before processing each input. Starting at S, the first 0 changes the state to T.
Both following 1 inputs keep the machine in T and produce 1. The final 0 changes T to S and produces 0.
Since this is a Mealy machine, each output is attached to the transition taken.
Common mistake
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