Introduction to Mealy and Moore Machines

Introduction: - These are the finite Automata with output

The tuples are like

  • Q:    is a finite set of states.
  • q0:   is the initial state.
  • ∑ :   is the input alphabet.
  • \Delta:  is the output alphabet.
  • δ:    is an input transition function which maps Q×∑ → Q.
  • λ:    is the output function which maps Q → O.

Moore machine: In Moore machine output is associated with each state. Here output depends on the present state.

The output function is λ: Q → \Delta

it has more states than Mealy Machine.

Mealy machine: In Miley machine output is dependent on the current state as well as present input

The output function is λ: Q ×∑  →\Delta

 It has fewer states than Moore Machine.


When you are doing conversions from Mealy machine to Moore machine, the no. of states may be increased. But when from Moore to Miley no. of states are remain the same.