Mealy machine

In the theory of computation, a Mealy machine is a finite-state machine whose output values are determined both by its current state and the current inputs. (This is in contrast to a Moore machine, whose output values are determined solely by its current state.) A Mealy machine is a deterministic finite-state transducer: for each state and input, at most one transition is possible.

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

A Mealy machine is a 6-tuple ${\displaystyle (S,S_{0},\Sigma ,\Lambda ,T,G)}$ consisting of the following:

In some formulations, the transition and output functions are coalesced into a single function ${\displaystyle T:S\times \Sigma \rightarrow S\times \Lambda }$.

...
Wikipedia