Reversible gates can be easily fabricated at the chip level using optical computing. This paper presents a systematic design of reversible gate based on qca. Then, a modification of a conventional logic synthesis procedure. Realization of digital fuzzy operations using multivalued. Learning why you buy integrated circuits four bit johnson counter. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. Microelectronics journal, 25 1994 437441 modified fredkin gates in logic design p. Some logic gates like not gate or inverter has only one input and one output. In this lesson, we will learn how, given a specification, to design the corresponding logic circuit using basic logic gates. Design of control unit for low power alu using reversible logic ravish aradhya h v, praveen kumar b v, muralidhara k n abstracttechnology advances in vlsi designs offer exponentially shrinking device dimensions and exponentially growing circuit complexities. A modified form of fredkin gate can be used to design any multivalued combinational and sequential logic system p.
In contrast to earlier methods, our solution deploys a simple and regular cascade structure composed of lowcost gates which enables significant reductions with respect to quantum costs. The fredkin gate also cswap gate is a computational circuit suitable for reversible computing, invented by edward fredkin. They are the building blocks of quantum circuits, like classical logic gates are for conventional digital circuits unlike many classical logic gates, quantum logic gates are reversible. Picton department of electronic systems engineering, faculty of technology, the open university, walton hall, milton keynes mk7 6aa, uk i l f a modified fredkin gate is proposed as a basic building block for lowenergy computing. The purpose of this paper is to give a frame of reference, understanding and overview of reversible gates. Determine its worstcase carry delay using the characteristics of the gates in table 2. 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. There are several advertised advantages to fredkin gates that do not necessarily work as expected in real circuits. A modified fredkin gate is proposed as a basic building block for lowenergy computing. If one or more of an and gate s inputs are false, then the output of the and gate is false. Basic digital logic gates perform logical operations of and, or and not on binary numbers. Essentially the modified fredkin gate is a simple crossover switch, but it. Logic optimization is interesting and difficult for two reasons. This paper shows that the modified fredkin gate can be used to implement multivalued logic, threshold logic and array logic.
The reversible mux gate and feynman gate is used for designing the jk flipflop. Introduction in other lessons, we covered basic boolean logic aspects. According to the theory of reversibility, any reversible logic gate will. Compare with a carryskip adder with group size of four. In this paper various logic gates and its applicability on logic design have been. A design for testability technique for quantum reversible. In this paper one particular gate is proposed which has the potential to be implemented optically.
Logic design covers binary numbers, logic gates, multiplexors and more. By the combination of these gates, we can obtain any boolean or logical functions or logical function. Logic gates are the basis of decision making for electronic devices. In this paper, a modification of the fredkin gate is proposed. An and gate is a digital logic gate with two or more inputs and one output that performs logical conjunction. Design of control unit for low power alu using reversible. We need to learn about gates and boolean algebra that are foundations of logic design. For privacy reasons, a voting booth can only be used if the booth on either side is unoccupied. Recently, researchers have also implemented reversible logic gates such as toffoli gate, peres gate and modified fredkin gate using different schemes like semiconductor optical amplifier soa. Picton, modified fredkin gates in logic design, microelectronics j.
The fredkin ga te also cs wap g ate is a computational circuit suitable for reversible computing, invented by e dward fr edkin. In this paper, we introduce a new method to realize symmetric functions with reversible circuits. Keywords feynman gate, fredkin gate, garbage output. Introduction to logic gates using transistor technology, we can create basic eve engels, 2006 slide 1 of 20 logic gates. Gates are simplest digital logic circuits, and they implement basic logic operations functions. In this tutorial, we will have a brief introduction to logic gates. Basics of digital logic design presentation d cse 675. Fredkin is also popular as a universal gate for reversible logic circuits just. Our realization of quaternary toffoli gate is more efficient than the previous realization and other quaternary circuits are realized for the time in literature. From switches to transistors, logic gates and logic circuits hakim weatherspoon cs 3410, spring 20 computer science cornell university. While you will likely never need to build your own logic gate, with the. A block carrylookahead module bcl a generates only the ms carry bit in a group as shown in figure 2.
In this way, logic gates are analogous to functions in mathematics. Sep 07, 2015 logic design covers binary numbers, logic gates, multiplexors and more. The truth table for an and gate with two inputs appears to the right. Jul 29, 2015 materials for gate preparation in digital logic. Design of low power decoder using modified reversible logic gates. The result is that the same basic architecture can be used to implement many different logic design techniques, so that comparisons can be made between them. Reversible circuit synthesis of symmetric functions using. Logic gates are the bricks and mortar of digital electronics, implementing a logical operation on one or more binary inputs to produce a single output. The output of a gate provides two nominal values of voltage only, e. In this paper various logic gates and its applicability on logic design have been discussed. The fred kin gate is a circuit or device with three inputs and three outputs that transmits the first bit unchanged and swaps the last two bits if, and only. We may not have a logic gate for every possible function, or even for every function of. For the love of physics walter lewin may 16, 2011 duration.
Fredkin gate is a very common reversible logic gate. We present the design of quaternary quantum version of reversible circuits such as toffoli gate, modified fredkin gate, mux, demux, encoderdecoder using linear ion realizable quaternary muthukrishnanstroud gates. Gate inputs are driven by voltages having two nominal values, e. Logic gates digital circuit that either allows a signal to pass through it or not. Basics of digital logic design computer science and. Binary systems, boolean algebra, logic gates, analysis or design of combinatorial circuits, synchronous sequential logic, registers, counters and memory, laboratory experiments in digital circuits and logic logic design, contemporary logic design, switches. There are entire fpga boards strictly using reversible logic gates that are implemented using fredkin and toffoli gate as their lus.
Specifically, you will be implementing the nor only combinational logic circuits for the two outputs. Aabu practice implement a 3input nor gate with cmos. Boolean logic gates acting on some binary input in order to solve various problems by composing the gates. One of them is the kmap or the karnaugh maps, and the other is the quinemccluskey algorithm. Pdf a quantitative approach of reversible logic gates in qca. From transistorsto logic gates and logic circuits prof.
There are several problems effecting their widespread usage in computer architecture. Part of the lecture notes in computer science book series lncs, volume 7948. Materials whose refractive index is changed owing to the applied. Indepth comparative analysis of reversible gates for designing. Jun 29, 2016 for the love of physics walter lewin may 16, 2011 duration. Logic gates are basically are group of three basic logic gates specifically called as not, and and or gate.
The problem i have is with these two questions that are in the picture, it says build an and, or and not gate using logics 0,1 and one fredkin gate and then after build an xor with two fredkin gates. The basic operations are described below with the aid of truth tables. Hence this gate is known as controlled swap gate cswap. Free logic circuits books download ebooks online textbooks. Ok so i am studying for an exam which is about logic gates and circuits, etc. Project on logic gates in physics pdf a logic gate is an idealized or physical device implementing a boolean function, that is. How to create an and, or, xor and not gates with a. Fredkin gates as a basis for comparison of different logic design solutions abstract. The importance of nand nand gates are considered to be the universal gate, because any other gate can be synthesized eve engels, 2006 slide 22 of 20 using nand. All the gates have their own identical logical function. In this chapter we will discuss how the notions of logic gates need to be modified in the quantum context and how they are used in the solution of the problems. Numerous reversible gates has also been proposed for designing logic circuits apart of basic quantum controlled toffoli and fredkin gates. He describes the use of fredkin gates to build clocked dtype latches, which can then be combined to form more complex memory elements required in sequential logic design.
Using the combination of fredkin and feynman gate a new gate known as sayem gate was proposed by sujata. The circuit shown is a 4bit counter, comprised of dtype flip flops connected in series, with data connected to q over and over, until you get to the last one, where notq is connected back to the first data. Write a logic function that is true if and only if x contains at least two 1s. Implementation of symmetric functions using quantum dot. In general, there is only one output to a logic gate. Transistors are used to build logic gates logic gates make up functional and control units microprocessors contain several functional and control units. Quantum gates modern computers are built using logic gates. Show a onelevel structure similar to a onelevel cla for a 32bit adder constructed only from these bcla modules, halfadders, and fulladders. Logic gates are primarily implemented electronically using diodes or. In quantum computing and specifically the quantum circuit model of computation, a quantum logic gate or simply quantum gate is a basic quantum circuit operating on a small number of qubits.
Implementation of symmetric functions using quantum dot cellular automata. Demonstration of an alloptical fredkin gate request pdf. Digital systems, number systems and codes, boolean algebra and switching functions, epresentations of logic functions, combinational logic design, combinational logic minimization, timing issues, common combinational logic circuits, latches and flipflops, synchronous sequential circuit design. The knowledge gained in the last chapter on fabrication is important for combinational logic designtechnologydependent parameters for minimum size, spacing, and parasitic. R1 r0 r2 what kind of hardware can add two binary integers. An optimized design of reversible sequential digital circuits arxiv. Divided into 20 easytograsp study units, the book covers such fundamental concepts as boolean algebra, logic gates design, flipflops, and state machines. See more ideas about computer science, electrical engineering and logic design. The goal of logic design or optimization is to find a network of logic gates which together compute the combinational logic function we want. It has the advantage that, if necessary, it can perform conventional boolean logic, but it can also perform alternative logics such as conservative logic, multi. There are different ways to design logic gates, for instance the diagram to.
Given a truth table that specifies a logic circuits behaviour, design the equivalent circuit. Design of basic logic gates using nor gate not, or and. Optimized design of the universal ternary gates for quantum. Understanding logic design appendix a of your textbook does not have the needed background information. Note there are no constraints on the number of gate inputs. In recent years, reversible logic has emerged as a promising computing paradigm having application in low power cmos, quantum computing, nanotechnology, and optical computing. Design of alu using reversible gates and vectored logic 2 it is a 33 fredkin gate. The inputs of the logic gates are designed to receive only binary data only low 0 or high 1 by receiving the voltage input. There are a few formal methods of approaching this problem and are well documented. There was another method which was quite tedious which i had learnt, unfortunately i dont remember it now. A modified pattern of fredkin gate, mcl gate and a new scheme of urg gate, bjn. Modified fredkin gates in logic design sciencedirect. Can implement with multiple twoinput gates, or with single cmos circuit. By combining flipflops with networks of logic gates, students will learn to design counters, adders, sequence detectors, and simple digital systems.
In this worksheet were going to look at the basic logic gates, and, or, and not, how they are made, and what you can do with them. The optical implementation of reversible logic gates are based on semiconductor optical amplifier soabased machzehnder interferometer mzi. Fredkin gates as a basis for comparison of different logic. Design of optical reversible logic gates using electrooptic.
How to create an and, or, xor and not gates with a fredkin. Logic gates and boolean algebra combinational logic arithmetic circuits and common msi logic circuits synchronous sequential circuit design latches, flipflops, registers, and counters nmos and cmosbased logic gates computer organization. In fact, most gates are implemented in solidstate ttl chips transistortransistor logic e. The block diagram shown below represents a voting booth monitoring system. Data representation and number system, binary logic, basic gate, combined gates, boolean algebra, combinational circuit, designing combinatorial circuits, sequential circuit, register, tristate logic and memories. Reversible logic gates are circuits that have the same number of inputs and outputs and have onetoone and onto mapping between vectors of inputs and outputs. Alloptical circuit of this modified fredkin gate mfg is also designed using. In this video we go over binary numbers and basic logic gates and, or. Reversible circuit synthesis of symmetric functions using a simple. Design of alu using reversible gates and vectored logic 3 adding more number of full adders and are interconnected as shown in the figure. It is universal, which means tha t any l ogical or arithmetic operation can be constructed enti rely of fredkin gates. Design of alu using reversible gates and vectored logic 1 design of alu using reversible gates and vectored logic.
Design of reversible addersubtractor and its mapping in. A gate is an electronic device which is used to compute a function on a two valued signal. Logic gates use switch behavior of mos transistors to implement logical functions. It is universal, which means that any logical or arithmetic operation can be constructed entirely of fredkin gates. The table below summarize all the basic digital gates and their characteristics.
The purpose of this tabloid is to give a mount of reference, empathetic and indication of reversible gates. Logic gates 4 oo software design and construction 2input logic gate hierarchy it is sensible to view each of the 2input logic gates as a specialized subtype of a generic logic gate a base type which has 2 input wires and transmits its output to a single output wire. On the other hand, in optical technologies, few designs of reversible logic gates have been proposed such as demonstration of an alloptical fredkin gate proposed by poustie, using terahertz. The machzehnder interferometer has advantages such as high speed, low power, easy fabrication, and fast switching time. After this work more research has been done on sequential circuits using reversible gates. Multivalued sequential logic design using fredkin gates. When you write add add r0, r1, r2, you imagine something like this. The input and output for a logic gate is in the form of bits binary digits which are either 1s or 0s. Basic logic gates and gate the and gate is an electronic circuit that gives a high output 1 only if all its inputs are high. Gates are used to build more complex circuits that implement more complex logic functions. Example given logic equations, it is easy to design a corresponding. Design is fundamental to our lives, for it is really about the making of things, which is the business of artists. Design of reversible logic circuits using quantum dot cellular. In this activity you will revisit the voting booth monitoring system introduced in activity 2.
Introduction to logic gates not, and, nand, or, nor. Design of control unit for low power alu using reversible logic. The fredkin gate is a circuit or device with three inputs and three outputs that transmits the first bit. Binary systems, analog vs digital, digital systems, binary numbers, number base conversions, compliments, octal and hexadecimal numbers, signed binary numbers, nary logic, boolean algebra and gate level minimization, design of combinational circuit, design of sequential circuits, memory. The digital logic gate is the basic building block from which all digital electronic circuits and microprocessor based systems are constructed from.
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