A digital multiplexer or data selector is a logic circuit that accepts several inputs and selects one. Electronicsmultiplexers wikibooks, open books for an. Multiplexer and demultiplexer is a combinational of digital logic switching. Multiplexer simple english wikipedia, the free encyclopedia. Few types of multiplexer are 2to1, 4to1, 8to1, 16to1 multiplexer. The multiplexer used for digital applications, also called digital multiplexer, is a circuit with many input but only one output. Types of multiplexers fdm, tdm, wdm and dwlm etc with their applications. An electronic multiplexer can be considered as a multipleinput, singleoutput switch, and a.
In contrast, analog circuits manipulate analog signals whose performance is more subject to manufacturing tolerance, signal attenuation and noise. You can refer to the wikipedia article about the mulitplexer to understand how a digital multiplexer works internally. But, what is required is a device that will allow us to select. A multiplexer is used to transmit the data signals from the computer system of a satellite to the ground system by using a gsm communication. Digital muxes amplify the signal, since the internal gates are, after all, buffer amplifier. If digital signals are multiplexed, then this type of multiplexer is called digital multiplexer. Shown here is a multiplexer and a demultiplexer, each using a multipleposition switch symbol to indicate the selection functions inside the respective circuits. Conceptually a digital multiplexers functionality is the same as an analog one, only it handles everything digitally. Multiplexers, or muxs, can be either digital circuits made from high speed logic gates used to switch digital or binary data or they can be analogue types using. Multiplexers combinational logic functions electronics.
In electronics, a multiplexer also known as a data selector, is a device that selects between several analog or digital input signals and. Demultiplexers take one data input and a number of selection inputs, and they have several outputs. Digital electronics the most scoring subject in gate ee. Multiplexers can be used as lookup tables to perform logic functions. Codrey electronics deals with electronic circuits, arduino projects and embedded systems. A multiplexer of 2 n inputs has n select lines, which are used to select which input line to send to the output. A multiplexer is a device that brings the concept of a rotary switch in analog electronics to the digital side. Mux sends digital or analog signals at higher speed on a single line in one shared device. A digital device capable of selecting one input out of its multiple input lines and forwarding it on a common output line is called a multiplexer.
For n input lines, log n base2 selection lines, or we can say that for 2 n input lines, n selection lines are required. For digital application, they are built from standard logic gates. The book digital electronics contains twelve chapters with comprehensive. Because the output is a compressed version of the input, multiplexing is an effective and inexpensive way to transmit and share information via telecommuting or a computer network. Therefore, this is all about what is multiplexer and their types. Digital electronics multiplexer demultiplexer this presentation will demonstrate the basic function of the multiplexer mux. By applying control signals, we can steer any input to the output. The term multiplexer, and the abbreviation mux, are often used to also mean a demultiplexer, or a multiplexer and a demultiplexer working together. The books that you can refer for the theory are digital circuits by a. In most cases a digital multiplexer is a digital selector. Digital techniques are helpful because it is much easier to get an electronic device to switch into one of a number of known.
Digital icscombinational logic renesas electronics. A 4to1 mux designed with small scale integration ssi. The selection of the channel to be read into the output is controlled by supplying a specific digital word to a different set of inputs select inputs. The multiplexer is one of the basic building blocks of any digital design system. Multiplexer is a device that has multiple inputs and a single line output. In any communication system that is either digital or analog, we need a communication channel for transmission. Multiplexer handle two type of data that is analog and digital. In analog circuit design, a multiplexer is a special type of analog switch that connects one.
What is the difference between an analogue multiplexer and. Spring 2011 ece 301 digital electronics 3 multiplexers a multiplexer has 2n data inputs n control inputs 1 output a multiplexer routes or connects the selected data input to the output. It is a device which, based on some input, will change the connection of its other inputs to its outputs. Digital circuits are made from highspeed logic gates. A basic idea regarding the initial concepts of digital electronics is enough to understand the topics covered in this tutorial. A multiplexers mux is a device that allows digital information from several sources to be routed onto a single line for transmission over that line to a common destination.
These find application in various realms of digital and as well as analogue electronics. Codrey electronics electronics and embedded systems. Analog types use transistors or relays for switching the current or voltage inputs to a single output. Digital circuits contain a set of logic gates and these can be operated with binary values, 0 and 1. This is the reason multiplexers are often termed as data selectors. Multiplexers and demultiplexers worksheet digital circuits. Multiplexers, or mux s, can be either digital circuits made from high speed logic gates used to switch digital or binary data or they can be analogue types using transistors, mosfet s or relays to switch one of the voltage or current inputs through to a single output. It recovers the separate signals at the receiving end. Although they appear similar, they certainly perform different functions. To learn working principle of multiplexer to use of multiplexer theory. The term multiplexing can have multiple interpretations. Multiplexers can also be expanded with the same naming conventions as demultiplexers. It is a combinational circuit which have many data inputs and single output depending on control or select inputs.
Both demultiplexers and multiplexers have similar names, abbreviations, schematic symbols and circuits, so confusion is easy. Hope you might have got some fundamental concepts about this topic by observing the digital logic circuits and their applications. Whenever the transmission capacity of a medium linking two devices is greater than the transmission needs of the devices, the link can be shared in order to maximize the utilization of the link, such as one cable can carry a hundred channels of tv. Tdm repeatedly transmits a fixed sequence of time slots over a single transmission channel. At a time, one signal can be placed on the one line. A multiplexer is a signal switcher that selects an. In digital electronics, a multiplexer is a combination of logic gates resulting into circuits with two or more inputs data inputs and one output. The most basic type of multiplexer device is that of a oneway rotary. Algebraic manipulation as seen in examples karnaugh k mapping a visual approach tabular approaches usually implemented by computer, e. We can have n control bits to select from 2n input bits. A multiplexer of 2n inputs has n select lines that will be used to select input line to send to the output.
Gate multiple choice questions, gate guide, and the gate cloud series. So when you hear about a multiplexer, it may mean something quite different. Take as an example the common 74hc151 digital mux and its internal logic diagram. In general, a 2 ninput multiplexer can be programmed to perform any ninput logic function by. Multiplexing is the process by which multiple analog signals and data streams are output as one signal. This article explains different types of demultiplexers. Digital electronics, digital technology or digital electronic circuits are electronics that operate on digital signals. Basic electronics and electrical tutorials and guides chapter wise fro electrical and electronics engineering students. Digital circuits multiplexers multiplexer is a combinational circuit that has maximum of 2n data inputs, a na selection lines and single output line. The multiplexer used for digital applications, also called digital multiplexer, is.
For analog application, multiplexer are built of relays and transistor switches. In the largescaledigital systems, a single line is required to carry on two or more digital signals and, of course. Multiplexers can select data input lines as per our requirement. This tutorial is meant for all the readers who are aspiring to learn the concepts of digital circuits. In electronics, a multiplexer or mux occasionally the term muldex is also found, for a combination multiplexerdemultiplexer is a device that selects one of many analog or digital input signals and outputs it into a single output line. In the following article we will discuss the construction and operataion of multiplexer and demultiplexer in detail. Multiplexer in a network multiplexers can either be digital circuits or analog types. Harris, digital design and computer architecture, morgan kaufmann.
Digital electronicsasychronous devicedigital multiplexer. Multiplexers and demultiplexers are often confused with one another by students first learning about them. Multiplexing circuits are called multiplexer or mux. Multiplexing, demultiplexing, asynchronous, synchronous. Digital circuits multiplexers multiplexer is a combinational circuit that has maximum of 2n data inputs, a. It is not practical to allocate individual channels for each user. The multiplexer mux the operation of sending one or more analog or digital signals over a common transmission line at different times or speeds is known as multiplexing, and the device used to do this is known as multiplexer. Multiplexer mux and multiplexing tutorial electronicstutorials. Multiplexer is a crucial combinational circuit which is used in various significant application. Books embedded systems 7 best books to learn embedded systems that excels your career. It is a combinational digital circuit and generally called a data selector as well. Different types of digital logic circuits with working. A multiplexer or mux is a device that selects one of several digital input signals and directs it to a single output.
Functions of multiplexers in a data communication network. The value of the control inputs determines the data input that is selected. Digital electronics part i combinational and sequential logic dr. J hoolan, in telecommunications engineers reference book, 1993. A multiplexer of inputs has select lines, which are used to select which input line to send to the output. An electronic multiplexer is a multipleinput, singleoutput switch. A 4to1 multiplexer circuit is that is the formal definition of a multiplexer. The select lines determine which input is connected to the output, and also to increase the amount of data that can be sent over a network within certain time. The multiplexer data inputs are connected to 0 or 1 according to the corresponding row of the truth table. Multiplexers, or muxs, can be either digital circuits made from high speed logic gates used to switch digital or binary data or they can be analogue types using transistors, mosfets or relays to switch one of the voltage or current inputs through to a single output. Different types of digital logic circuits with working conditions a digital logic circuit is defined as the one in which voltages are assumed to be having a finite number of distinct value. Multiplexers are also known as data n selector, parallel to serial convertor, many to one circuit, universal logic circuit. It is a process of taking information from one input and transmitting over one of many outputs. Multiplexers are mainly used to increase the amount of data that can.
Types of digital logic circuits are combinational logic circuits and sequential logic circuits. Now, i would be discussing the chapters that you have to study in detail along with the topics that have to be studied in each chapter. Digital electronics part i combinational and sequential. Mux sends digital or analog signals at higher speed on a single line in one. In this session, part 2 of digital circuits, we will look at digital ics and combinational logic. An simple example of an non electronic circuit of a multiplexer is a single pole. Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link. John crowe, barrie hayesgill, in introduction to digital electronics, 1998. Of the available types, the timedivision multiplexer is more complex, and the digital multiplexer is more important in applications. The most prominent distinction between a multiplexer and demultiplexer is that a multiplexer takes two or a lot of signals and encodes them on a wire, whereas a demultiplexer reverses what the multiplexer does. Short for time division multiplexing, a type of multiplexing that combines data streams by assigning each stream a different time slot in a set. Therefore a group of signals are combined together and sent over a common channel.
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