GATE CSE IT » Difference Between Mealy Machine And Moore Machine

Difference Between Mealy Machine And Moore Machine

Table of Contents

  1. What is a Mealy Machine?
  2. What is a Moore Machine?
  3. Difference between a Mealy Machine and a Moore Machine

Pattern recognition is accomplished using finite automation. It takes a symbol string as input and modifies its state accordingly. When the appropriate symbol is discovered, the transition takes place. The automation can either advance to the following state or remain in the current state during transition. 

Restricted automata have two states: Accept and Reject. When the incoming string is successfully processed, and the automaton has achieved its final state, it will accept. Finite automata can contain outputs for each transition. Finite state machines (FSM) are machines with many states. These systems are serial circuits with a restricted variety of ways in which their past might influence their future behaviour. They are also employed because no machine has an endless storage capacity. 

State transition machines that produce output are classified into Moore Machine and Mealy Machine. In the Mealy machines, the output values are determined by both the present input and the present state. The output values of a Moore Machine are determined only by their current condition.

What is a Mealy Machine?

A Mealy machine is a deterministic finite machine with an output value instead of a final state. The integer linear program is a corresponding output for a given input. The Mealy machine’s output is determined by the current condition of the FA in addition to the input sequence symbol.

 Unlike other machine codes that determine the acceptability of a specific string in a known language, Mealy machines evaluate the output against the provided input. The reaction takes place during the same clock cycle. When the intake logic is completed in the current state, the output function’s value becomes a combination of transitions and modifications.

A Mealy Machine typically requires only a few states for both synthesis methods. For each input letter/string, it generates an equivalent output string. The size of the input sequence in this machine is proportional to the size of the Turing machine’s return string, which is n. When the current state of the input logic is completed, the output function’s value function has become a function of jumps. The Mealy machinery has six tuples. They are:

  • Q – It consists of a finite collection of states.
  • ∑ – The input alphabet is a defined set of symbols.
  • O – The output alphabet is a defined set of symbols denoted by the O.
  • Δ – It is the input process stage.
  • X – It is the production transition function.
  • q0 – It is the starting point from which any input is evaluated.

What is a Moore Machine?

Moore’s machine is a discrete state system in which the present condition and present input symbol determine the future state. The production symbol at any given time is determined solely by the machine’s current state. A Moore Machine has more states than a Mealy Machine. Its output is independent of the current input. 

It is solely dependent on its present state. Its output is placed on the transition. When the state changes, the production function’s value becomes a result of the current state and the modifications at the clock’s edges. Both the state and the output change synchronized to the edge of the clock. Moore machine is described by six tuples (Q, ∑, q0, O, δ, λ) where,

  • Q: a limited number of states.
  • q0: machine’s initial state.
  • ∑: a limited number of input symbols.
  • O stands for output alphabet.
  • δ: transition function where Q 
  • λ: output function in which Q → O

Difference between Mealy Machine and Moore Machine

Mealy MachineMoore Machine
When the load varies, so does the output.When the load varies, the output changes.
Output is determined by both the current state and the current input.The current situation solely determines the output.
There are fewer states needed.Additional states are needed.
Extra hardware is required for the proposed circuit.For circuit implementation, minimal hardware is required.
Asynchronous output generation.Output synchronisation and condition generation.
They respond to inputs more quickly.They respond to inputs more slowly.
Transitions are used to place the output.Output is assigned to states.
Designing is challenging.Designing is simple.
The counter cannot be referred to as a Mealy Machines.The counter is known as a Moore Machinery.
When the intake logic in the current state is completed, the output function’s value function combines the transition and modifications.The output function’s value is based on the existing state and varies at the clock boundaries whenever condition changes occur.