Construct a Mealy machine M that takes as input strings of 0’s and 1’s. Its output
is to be a string of 0’s until the first 1 occurs in the input, at which time it will
switch to printing 1’s. This is to continue until the next 1 is encountered in the
input, when the output reverts to 0. The alternation continues every time a 1 is
encountered. For example, F M (0010010) = 0011100. This fst is a simple model
for a flip-flop circuit. Figure A.2 shows a solution.
Figure A.2
A.3 Moore Machines
Moore machines differ from Mealy machines in the way output is produced. In a
Moore machine every state is associated with an element of the output alphabet.
Whenever the state is entered, this output symbol is printed. The output is
produced only when a transition occurs; thus, the symbol associated with the
initial state is not printed at the start, but may be produced if this state is entered
at a later stage.
Definition A.2
A Moore machine is defined by the sextuple
M = (Q, ∑, Γ, δ, θ, q 0 ),
where
Q is a finite set of internal states,
∑ is the input alphabet,
Γ is the output alphabet,