Mealy machine

A simple Mealy machine has one input and one output.

Mealy machines provide a rudimentary mathematical model for cipher machines.

The tagger can be implemented as a finite state automaton (Mealy machine)

More complex Mealy machines can have multiple inputs as well as multiple outputs.

The Richards controller is a Mealy machine since its output is dependent on both the current state and the input.

This is in contrast to a Mealy machine, whose output values are determined both by its current state and by the values of its inputs.

A Mealy machine is a deterministic finite state transducer: for each state and input, at most one transition is possible.

UML state machines have the characteristics of both Mealy machines and Moore machines.

The number of states in a Moore machine will be greater than or equal to the number of states in the corresponding Mealy machine.

For the subsequent discussion a State Machine will be defined as the following tuple of values (See also Mealy machine and Moore Machine):

The difference between Moore machines and Mealy machines is that in the latter, the output of a transition is determined by the combination of current state and current input.

The Mealy machine is named after George H. Mealy, who presented the concept in a 1955 paper, "A Method for Synthesizing Sequential Circuits".

Kari reduced the size of this set to only 14, by finding a set of tiles that (when used to tile the plane) simulates the construction of a Beatty sequence by Mealy machines.

The state diagram for a Mealy machine associates an output value with each transition edge (in contrast to the state diagram for a Moore machine, which associates an output value with each state).

They support actions that depend on both the state of the system and the triggering event, as in Mealy machines, as well as entry and exit actions, which are associated with states rather than transitions, as in Moore machines.

In fact, in a classical Mealy machine, actions are associated exclusively with state transitions, so the only way to execute actions without changing state is through a self-transition (depicted as a directed loop in Figure 1 from the top of this article).

Every Moore machine M is equivalent to the Mealy machine with the same states and transitions and the output function that takes each state-input pair (q,x) to G(q), where G is M's output function.

Considering the input and output alphabet the Latin alphabet, for example, then a Mealy machine can be designed that given a string of letters (a sequence of inputs) can process it into a ciphered string (a sequence of outputs).