Finite State Machines MCQ Quiz in తెలుగు - Objective Question with Answer for Finite State Machines - ముఫ్త్ [PDF] డౌన్‌లోడ్ కరెన్

Here, x(k) denotes the previous state.

Explanation:

A sequential circuit is a type of digital circuit whose output depends not only on the present value of the input but also on the past inputs. To store previous inputs, sequential circuits use a Memory element.

A synchronous sequential circuit is also called a finite state machine (FSM) if it has a finite number of states.

Special note:

There are two types of FSM’s:

Mealy state machine: An FSM is called a Mealy state machine if the output depends on both the present input and present states. 

Moore state machine: An FSM is called a Moore state machine if the output depends only on the present states.

Concept:-

• According to input sequence we must move from one state to other state.
• Every state will only have two outgoing branches
• Incoming branches may be more than two or less then two possible.

Analysis:-

let, x = 011 011 0001

After following the input sequence, we obtain output as logic 1 at three instance.

∴ For given sequence, logic 1 will come for 3 times.

Explanation:

S⁺ = S̅ Y̅ + S X

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

1. Mealy Machine

2. Moore machine

Option-1) A Mealy Machine is an FSM whose output depends on the present state as well as the present input.

Option-2) A Moore Machine that its output depends only on the present state of the memory elements. The external inputs do not influence the outputs.

​Option-3) The implementation of a logic function in the Mealy circuit needs fewer states than the Moore circuit.

Key Points

Concept and Explanation:-

                                                              (Only one clock cycle later)

Explanation:-

In Melay machine output is depend upon present state as well as present input. So it is output capable machine.

→ hence react faster to input

[Statement 1 false]

→ Due to dependant of both present state and present input extra hardware circuitary required during implimentation. So that melay machine is complex in designing.

[Statement 2 correct]

• More information:-

Melay Machine

Moore type:-

• For n bit sequence detector moore required (n + 1) state
• For n bit sequence detector melay require n state

Concept:

The basic idea of an FSM is to store a sequence of different unique states and transition between them depending on the values of the inputs and the current state of the machine.

A Finite State Machine (FSM) formulation is used to describe the processes during which information or tasks move from one state to another for action, according to a set of rules.

The FSM can be of two types:

1. Moore (where the output of the state machine is purely dependent on the state variables) and
2. Mealy (where the output can depend on the current state variable values AND the input values).

The general structure of an FSM is shown in Figure

The state diagrams of Mealy and Moore are shown below for an example.

Mealy

Moore FSM

Analysis:

The given FSM is Mealy and the analysis is explained below with the help of the table.

From the table, it is clear that the given FSM follows sequence 1101.

The state change is mentioned with bold letters for the respective input.

Conclusion

In option 3 the pattern is followed two times so it will give the output ‘1’ twice.

The given FSM is the sequence detector whose output is high when three consecutive ‘1’ s are input.

The given sequence

1) In Moore machine, output depends only on the present state

2) In Mealy machine, output depends on the present state and present input

3) The number of states in Moore is greater than the number of states in the Mealy machine. 

The block diagram explanation of the Mealy and Moore machine are as shown:

Moore Machine: In this automata, all the output symbols are associated with each state of finite state machine.

Specifications of Moore Machine:

\(M = (Q, \Sigma, \Delta, \delta, \lambda, q_0)\) is a 6-tuple notation, where 

• \(Q = \) set of finite states
• \(\Sigma = \) contains finite number of input symbols. Also called Input Alphabet.
• \(\Delta = \) contains finite number of output symbols. Also called Output Alphabet.
• \(\delta = \) it is a transition function. \(\delta : Q \times \Sigma \rightarrow Q\)
• \(\lambda = \) it is the output function. Output is associate with only state, \(\lambda : Q \rightarrow \Delta\)
• \(q_0 = \) it represents the initial state. \(q_0 \in Q\)

Mealy Machine: In this automata, all the output symbols are associated with transition state and transition input of the finite state machine.

Specifications of Mealy Machine:

\(M = (Q, \Sigma, \Delta, \delta, \lambda, q_0)\) is a 6-tuple notation, where 

• \(Q = \) set of finite states
• \(\Sigma = \) contains finite number of input symbols. Also called Input Alphabet.
• \(\Delta = \) contains finite number of output symbols. Also called Output Alphabet.
• \(\delta = \) it is a transition function. \(\delta : Q \times \Sigma \rightarrow Q\)
• \(\lambda = \) it is the output function. Output is associated with state and input, \(\lambda : Q \times \Sigma \rightarrow \Delta\)
• \(q_0 = \) it represents the initial state. \(q_0 \in Q\)

Important Points:

• Mealy and Moore Machines are 6-tuple notation automata.
• The only difference between them is in their Output Function.
• Moore Machine's output is associated with the state.
• Mealy Machine's output is associated with the state and input.

Hence the correct answer is option 3.