Setup in the scf file the input signals as shown below and draw the output f as obtained from simulation. A study of reversible logic gates and their applications. Reversible logic reversible logic realizes functions f. Nov 25, 2015 in modern technology logic circuits are found in several hightech devices including arithmetic logic units, computer memory and registers, multiplexers and decoderencoder. Is reversible logic really advantageous over irreversible logic in circuit design. A gate is an electronic device which is used to compute a function on a two valued signal. The goal of this paper is to develop a method to build singleoutput reversible logic circuits in regular and nonregular structures, in binary and ternary logic, with minimized number. Final advantages and disadvantages of reversible managed lanes january 2010 atlanta regional managed lanes system plan georgia department of transportation, office of planning 3 safety reversible facilities require additional safety precautions when compared to their bidirectional counterparts. Digital logic circuits types, application, advantage and. This advantage of reversible circuits over combinational circuits makes it more efficient. Review ontypesnumber of reversible logic gates and basic.
Introduction to reversible logic and mathematical derivation. Based on this, logic gates are named as and gate, or gate, not gate etc. Jun 19, 2019 in this tutorial, we will have a brief introduction to logic gates. The design can be optimized so as to produce minimum number of garbage outputs. The reversible logic circuits must use minimum number of constant inputs. A new approach of presenting reversible logic gate in. Basically, all logic gates have one output and two inputs. The machzehnder interferometer has advantages such as high speed, low power, easy fabrication and fast switching time. A truth table lists all possible combination of inputs and the corresponding outputs. Reversible logic gates helps to determine the outputs from the inputs and also the inputs can be uniquely recovered from the outputs. Therefore, as a proof of the fact that links and rotary joints su ce to create the combinatorial logic required for a turingcomplete computing system, fig. Logic gates are the basic building blocks of digital circuits or systems. Design and comparison of reversible and irreversible.
Within usefully broad limits, logic gates could be treated as ideal boolean devices without concern for electrical limitations. Sequential division circuit using reversible logic gates. Is reversible logic really advantageous over irreversible. Three articles that discuss some possible implementations of reversible logic and provide references to further reading are helical logic, by ralph c. I am designing reversible logic gates and multiplier circuit using those gates. Ashraful haque department of electrical and electronic. Logic gates are faster when it comes to solving any complex problems. Reversible computing is a model of computing where the computational process to some extent is time reversible. Not, and, or, and xor there are also other ones, such as nand, nor, and xnor that were not going to cover. Efficient simulationbased debugging of reversible logic. The advantage of established tools may also not be available.
Here, we investigate basic properties of reversible logic gates and circuits, which are needed in the following chapters. As the basic elements of any logic circuit, logic gates are used to realize boolean functions. Their advantages and disadvantages are discussed and potential use in biosensing systems, rather than in computing devices, is suggested. International journal of scientific research in computer. Fpga implementation alu based on reversible logic khushboo ahirwar1, sachin bandewar2, anand kumar singh3 1,2,3 department of electronics and communication, sssce, bhopal abstract programmable reversible logic is emerging as a prospective logic design style for implementation in. This creates trees of gates that depend on each other. Reversible gates versus balanced functions there exist 224 16,777,216 different truth tables with 3 inputs and 3 outputs.
The reversible 11 gate is not gate with zero quantum cost is as shown in the figure 1. In a model of computation that uses deterministic transitions from one state of the abstract machine to another, a necessary condition for reversibility is that the relation of the mapping from nonzeroprobability states to their successors must be onetoone. B reversible logic gates global scientific journal. Theresal, shanthi prince abstractconsidering the benefits of quantum and optics, if the logic gates in the quantum field and electronic structure are implemented using optical elements, then it will be benefited from advantages of quantum and design, and these processing. Logic gates actually look like weird bugs in real life. Final advantages and disadvantages of reversible managed lanes january 2010 atlanta regional managed lanes system plan georgia department of transportation, office of planning 2 distance highway trips within activity centers or from closer suburban areas to nearby. The three gates or, and and not, when connected in various combinations, give us basic logic gates such as nand, nor gates, which are the universal building blocks of digital circuits. A reversible logic gate is a memoryless logic element that realizes an injective logical function. They are the building blocks of any digital device, so in a nutshell digital devices wont work without them. The dissipation of heat is negligible and delay is less by using reversible logic gates. The relationship between the input and the output is based on a certain logic. From switches to transistors, logic gates and logic circuits hakim weatherspoon cs 3410, spring 20 computer science cornell university. This forms the basis of reversible logic where we have only one is to one correspondence bw the input and the output. The quantum cost of a reversible gate is the number of 22 reversible gates or quantum logic gates required in designing.
Reversible logic is similar to the convention logic but reversible logic circuits are constructing by reversible logic gates and conventional logic gates are designed by normal gates i. By combining reversible logic gates, reversible circuits can perform complex logical and arithmetic operations. Not, or, and and gates are the basic types of gates. Design constraints for reversible logic circuits 4. Digital logic circuits types, application, advantage and disadvantage. Sep 10, 2017 a gate or circuit that does not loose information is called reversible. It is also known as the controlledcontrollednot gate, which describes its action. In reversible logic design, there is k no of output fork no of inputs. Digital logic or gate digital gates electrical technology. Some logic gates like not gate or inverter has only one. This project will deal with the design of a 16 bit reversible arithmetic logic unit alu with 15 operations is presented by making use of double peres gate, fredkin gate, toffolli gate, dkg gate and not gate. Design and implementation of digital components using. Anne bracy cs 3410 computer science cornell university the slides are the product of many rounds of teaching cs 3410 by professors weatherspoon, bala, bracy, and sirer.
Reversible logic is becoming one of the potentialpower optimization techniquesin low power cmos design. The all optical implementation of reversible logic gates are based on semiconductor optical amplifier soa based machzehnder interferometer mzi. Mechanical computing systems using only links and rotary joints. Pdf a low power adder using reversible logic gates editor. A logic circuit consists of a number of a logic gates. Reversible circuits are fundamentally different from traditional irreversible ones. Basic logic gates types, functions, truth table, boolean. Atoms on a small scale behave like nothing on a large scale, for they satisfy the laws of quantum. Next will be discuss reversible arithmetic, specifically adders and comparators. Reversible logic gates, such as the double feynman gate, toffoli gate and peres gate, with 3. Fredkin gate, toffoli gate, interaction gate, and switch gate are typical ones. Logic gates types, working principle, application, advantage. Addition, subtractions operations are realized using reversible dkg gate and it compare with conventional gates. Introduction to logic gates not, and, nand, or, nor.
A gate or circuit that does not loose information is called reversible. I have designed wallace sign multiplier using reversible logic gates as well. Mar 31, 2015 a number of qcabased reversible logic gates, which are significantly smaller size than cmos have been presented here. In addition, qca design accomplished by the basic gate and logic circuit in which less area is required to make a device. Reversible electronic logic using switches pdf, by ralph c.
The fundamental physical concepts behind reversible logic. Thus the new device will consume less power and increase device performance. Next, the previously proposed alu in the literature. In the second part, a new method for converting irreversible functions to the reversible ones in qca technology is presented. Development of tool for mapping conventional circuit to reversible.
Reversible gates uses low power when compared to the conventional logic gates. Fundamentals of reversible logic gates and their applications. Mechanical computing systems using only links and rotary. In reversible logic, the fanout of every signal, including primary inputs is one. Bennett 3 showed that zero energy dissipation would be possible if the network consists of reversible gates only. We will see the different logic levels in ttl circuits, cmos circuits, some simple logic gates like or, not, nand, and, etc.
A number of qcabased reversible logic gates, which are significantly smaller size than cmos have been presented here. Reversible gates several reversible gates have been proposed over the years, e. Diode logic dl uses diodes to implement logical functions like and and or. Reversible logic circuits pawel kerntopf institute of computer science warsaw university of technology warsaw, poland. What is the difference between reversible logic gates and. Abstract reversible logic is one of the most vital issue at present time and it has different areas for its application, those are low power cmos, quantum computing, nanotechnology, cryptography, optical computing, dna computing, digital signal. The interconnection of gates to perform a variety of logical operation is called logic design. Abstractconsidering the benefits of quantum and optics, if the logic gates in the quantum field and electronic structure are implemented using optical elements. What is the exact advantage of reversible computing. Landauer has shown that for irreversible logic computations, each bit of. The benefits of logical reversibility can be gained only after employing physical reversibility. Implementing the reversible logic has the advantages of reducing gate counts, garbage outputs as well as constant inputs. This paper gives an overview of the reversible logic gates gathered from literature surveys.
Introduction basic concepts required to understand the reversible logic gates. Main goals of reversible logic synthesis is to minimize the garbage, to minimize the delay, to minimize the total number of gates, to minimize the width of the circuit. The digital system of qpsk is designed using a reversible logic gates which yields in low. Design and implementation of vedic multipliers using. A combinational logic circuit is reversible iff it contains only reversible gates it has no fanout it is acyclic as a directed multigraph theorem. Advantages of ttl logic family, one should have a basic idea about rtl, dtl etc. Reversible circuits are of particular interest in low power cmos vlsi design. Chapter 2 quantum gates when we get to the very, very small worldsay circuits of seven atomswe have a lot of new things that would happen that represent completely new opportunities for design. If a circuit is designed by using reversible logic gates the information loss is zero.
In this paper the implementation of three types of adder circuits using the reversible gate r are presented 1. This basic logic gate is the combination of and and not gate. Pdf reversible logic gates michael santhiya academia. Conventional circuit to reversible logic has been successfully carried out by piyush. However, the diagrams we use are easier to understand. Every future technology will have to use reversible gates in order to. Reversible logic fundamentals reversible gates basic. Design of sequential circuits using reversible logic has been presented in 7 and 8.
One of the most important features of a reversible gate is its garbage output i. This is called boolean logic in a circuit schematic each logic gate is represented by a different picture, like the ones shown below. Reversible gates some of the important reversible logic gates are. A new design and simulation of reversible gates in quantum.
Reversible logic gates has received great attention on power dissipation. The reversible logic gates are ninput and noutput logic gates. Reversible computing is a model of computing where the computational process to some extent is timereversible. A reversible circuit g consists of a cascade of reversible gates g i, i. Logic circuits are also used in upgraded technical microprocessors, some of which can contain over 100 million gates. Conclusion and future scope reversible logic gates form the building blocks of quantum computing. Logical operations are performed using boolean algebra which makes the circuit design more economical and simple. Tech, dept of ece, iec college of engineering and technology, u. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. Ashraful haque department of electrical and electronic engineering islamic university of technology, board bazar, gazipur1704, bangladesh. An output of one logic gate can be an input to another logic gate.
In this chapter we will look at the types of logic gates used within circuits and how the notions of logic gates need to be modi. In computer switching circuits, in which the logical boolean operation on data performed are called logic circuits or a circuit for performing the logical operations. The circuit actually operates in a backward operation, allows reproducing the inputs from the outputs and consumes zero power. Design of control unit for low power au using reversible logic. Logic gates not, or, and, nor, nand, xor, xnor gate, pdf. This paper provides the basic reversible logic gates, which in designing of more complex system having reversible circuits as a. Fredkin gate a block diagram b schematic representation. Also in the synthesis of reversible circuits direct fan out is not allowed as onetomany concept is not reversible. Design of reversible logic circuits using standard cells. In modern technology logic circuits are found in several hightech devices including arithmetic logic units, computer memory and registers, multiplexers and decoderencoder. In logic circuits, the toffoli gate also ccnot gate, invented by tommaso toffoli, is a universal reversible logic gate, which means that any reversible circuit can be constructed from toffoli gates. The number of triples of balanced functions is equal to 70 70 70 343 000 however, the number of reversible 3,3 gates is much smaller.
Fundamentals of reversible logic gates and their applications piyush singh m. From transistorsto logic gates and logic circuits prof. Also, logic gates are the building blocks of digital. Reversible logic circuits should have minimum quantum cost. Reversible logic fundamentals reversible gates basic regular reversible structures mirror circuits and spies. Reversible logic gates offer significant advantages such as high speed, low power, ease of fabrication etc. The first condition for any deterministic device to be reversible is that its input and output be uniquely retrievable from each other then it is called logically reversible. Logic gates are the basic building block of digital circuits. A reversible circuit has the facility to generate a unique output vector from each input vector, and vice versa. The energy savings of reversible logic gates is due mostly to the fact that they do not require entropy be created when an operation is performed. Bn, that map each input vector to a unique output vector. In current time, reversible logic gates are being used very fast due to its ability to design a more complex circuit with less power dissipation. Logic gates are the basic building blocks of any digital system. Reversible logic is one of the emerging technologies having promising applications in quantum computing.
Design and implementation 16 bit reversible logic alu with 15. There are several advertised advantages to fredkin gates that do not necessarily work as expected in real circuits. It is an electronic circuit having one or more than one input and only one output. A reversible circuit must have as many input wires as output wires permute the set of input values.
Outline gener al issues basic notions rever sible gates. Look at the below truth tables for better understanding. Also, circuits designed using these circuits would have better performance as compared to existing circuits. Design of all optical reversible logic gates request pdf. Design of all optical reversible logic gates kuki bordoloi, t. Reversible logic gate, quantum bits, mux, sequential circuits.
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