Finite automata may have outputs corresponding to each transition. There are two types of finite state machines (FSMs) that generate output −

1) Mealy Machine

2) Moore Machine

Mealy Machine

A Mealy Machine is an FSM whose output depends on the present state as well as the present input.

It can be described by a 6 tuple (Q, ∑, O, δ, X, q0) where −

Q is a finite set of states.

∑ is a finite set of symbols called the input alphabet.

O is a finite set of symbols called the output alphabet.

δ is the input transition function where δ: Q × ∑ → Q

X is the output transition function where X: Q × ∑ → O

q0 is the initial state from where any input is processed (q0 ∈ Q).

The state table of a Mealy Machine is shown below −

The state diagram of the above Mealy Machine is −

Moore Machine

Moore machine is an FSM whose outputs depend on only the present state.

A Moore machine can be described by a 6 tuple (Q, ∑, O, δ, X, q0) where −

Q is a finite set of states.

∑ is a finite set of symbols called the input alphabet.

O is a finite set of symbols called the output alphabet.

δ is the input transition function where δ: Q × ∑ → Q

X is the output transition function where X: Q → O

q0 is the initial state from where any input is processed (q0 ∈ Q).

The state table of a Moore Machine is shown below −

The state diagram of the above Moore Machine is −