Combinational logic circuits sequential logic circuits how digital logic gates are built using transistors. By setting the input to true, the demux behaves as a decoder. Whereas, 8x1 multiplexer has 8 data inputs, 3 selection lines and one output. The multiplexer mux the operation of sending one or more analog or digital.
Hef4067b all information provided in this document is subject to legal disclaimers. Another key difference exists for mux and demux is that multiplexer is n to 1 device but demultiplexer is 1 to n device. On the contrary, demultiplexer utilizes the control signal and allows us to have multiple outputs. Minimizes ic package count and logic design is simplified. A 4to1 mux designed with small scale integration ssi. Jul 23, 2015 the action or operation of a demultiplexer is opposite to that of the multiplexer. Multiplexers are also known as data n selector, parallel to serial convertor, many to one circuit, universal logic circuit. A demultiplexer function exactly in the reverse of a multiplexer, that is a demultiplexer accepts only one input and gives. Here the basic concept of mux is explained with truth table and circuit is also designed. A multiplexer or mux is a device that has many inputs and a single output.
The device or switching circuitry used to select and connect one of these several signals to the load at any one time is known as a multiplexer. For analog application, multiplexer are built of relays and transistor switches. 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. They forward the data input to one of the outputs depending on the values of the selection inputs. The demultiplexer does the reverse function of the multiplexer. Multiplexer data selectordigital electronicsenglish. Demultiplexer performs the reverse operation of the multiplexer i. There are three main ways of constructing a multiplexer.
John crowe, barrie hayesgill, in introduction to digital electronics, 1998 4. Multiplexing is the generic term used to describe the operation of sending one or more analogue or digital signals over a common transmission line at different times or speeds and as such, the device we use. The reverse of the digital multiplexer is the digital demultiplexer. For digital application, they are built from standard logic gates. In electronics, a multiplexer or mux is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. Multiplexer handle two type of data that is analog and digital. Multiplexer and demultiplexer are two devices very important in data communications. Important questions on multiplexer with answers in pdf for. Multiplexer with the help of control signals selects the particular input that has to be transmitted at the output. Spring 2011 ece 301 digital electronics 21 using a 2ninput multiplexer use a 2ninput multiplexer to realize a logic circuit for a function with 2n minterms. We can refer to a multiplexer with the terms mux and mpx too. With the use of a demultiplexer, the binary data can be bypassed to one of its many output data lines. The selection of the channel to be read into the output is.
A multiplexer takes parallel information and routes or funnels them onto a single serial line. With the use of a demultiplexer, the binary data can be. The 748 with three enable inputs has a flexible enabling system. It routes one signal input line to any one of the multiple output lines available at the output. It is a combinational circuit which have many data inputs and single output depending on control or select inputs. We can implement 1x8 demultiplexer using lower order multiplexers easily by considering the above truth table. Analog switches, multiplexers, demultiplexers maxim. A demultiplexer function exactly in the reverse of a multiplexer, that is a demultiplexer accepts only one input and gives many outputs. In this lesson we will study digital multiplexing in. Multiplexer is a combinational circuit that has maximum of 2 n data inputs, n selection lines and single output line. A 4 to 1 multiplexer uses 2 select lines s0, s1 to determine which. A 1 to 4 multiplexer uses 2 select lines s0, s1 to determine which one of the 4 outputs y0 y3 is routed from the input d.
The block diagram of 1x8 demultiplexer is shown in the following figure the common. The demultiplexer takes one single input data line and then switches it to any one of a number of individual output lines one at a time. Multiplexer in digital electronics pdf digital electronics basics chapter 5. In analog applications, multiplexers are made up of of. Demultiplexers provide the reverse operation of multiplexers since they allow a single input to be routed to one of n outputs, selected via m control lines n 2 m. Since, each 4x1 multiplexer produces one output, we require a 2x1 multiplexer in second stage by considering the outputs of first stage as inputs and to produce the final output. The selected line decides which ip is connected to the op, and also increases the amount of data that can be sent over an nw within a certain time. The term multiplexing can have multiple interpretations. Increases the capacity of low level channels into high level channels. The reverse of the digital demultiplexer is the digital multiplexer. The demultiplexer converts a serial data signal at the input to a parallel data at its output lines as shown below. Generally multiplexer and demultiplexer are used together, because of the communication systems are bi directional. 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.
Features, specifications, alternative product, product training modules, and datasheets are all available. The action or operation of a demultiplexer is opposite to that of the multiplexer. The multiplexer or data selector is a special combinational circuit that is one of the most widely used standard circuits in digital design. A 1 to 4 multiplexer uses 2 select lines s0, s1 to determine which one of the 4 outputs y0 y3 is routed from the input.
Logic circuit that performs the reverse operation of. If the output of the demultiplexer is 4 it can be termed as 1. So, we require two 4x1 multiplexers in first stage in order to get the 8 data inputs. One the input signals is a selection signal which chooses which signal gets to go out. One of these data inputs will be connected to the output based on the values of selection. Important questions on multiplexer with answers and pdf download, applications of multiplexer in digital system, multiplexers uses, multiplexing techniques. Sep 20, 2017 multiplexers are used to multiplex the data on single line. A multiplexer of 2n inputs has n select lines, which are used to select which input line to send to the output. Sep 04, 2015 multiplexer handle two type of data that is analog and digital.
This book is designed to meet the syllabus requirement of the b. Physically, a multiplexer has n input pins, one output pin, and m control pins. May 04, 2017 a multiplexer takes parallel information and routes or funnels them onto a single serial line. We can have n control bits to select from 2n input bits. For n input lines, log n base2 selection lines, or we can say that for 2 n input lines, n selection lines are required. The selected line decides which ip is connected to the op, and also increases the. Multiplexer mux data selectordigital electronicsenglish. The data distributor, known more commonly as a demultiplexer or demux for short, is the exact opposite of the multiplexer we saw in the previous tutorial the demultiplexer takes one single input. A typical example of a 3to8 line decoder demultiplexer, the 748, is shown in figure 5. Apr 15, 2017 multiplexer data selector digital electronics english.
The single pole multiposition switch is a simple example of nonelectronic circuit of multiplexer, and it is widely used in many electronic circuits. It is used to send a signal to one of the many devices. The multiplexer used for digital applications, also called digital multiplexer, is a circuit with many input but only one output. Digital electronics multiplexer demultiplexer this presentation will demonstrate the basic function of the multiplexer mux. Difference between multiplexer and demultiplexer with. Justin carl bejerano suba multiplexer a multiplexer, abbreviated mux, is a device that has multiple inputs and one output. The device or switching circuitry used to select and connect one of. In the following article we will discuss the construction and operataion of multiplexer and demultiplexer in detail.
In this lesson we will study digital multiplexing in which the number of inputs is a power of two 2, 4, 8, 16, and there is one output. Spring 2011 ece 331 digital system design 30 using a 2ninput multiplexer use a 2ninput multiplexer to realize a logic circuit for a function with 2n minterms. Digital electronicsasychronous devicedigital multiplexer. Thus, depending on the number of the outputs the demultiplexer is termed. Jul 19, 2017 the term multiplexing can have multiple interpretations.
In most cases a digital multiplexer is a digital selector. Demultiplexers can be used to implement general purpose logic. And if the outputs are 8 in number it can be termed as 1. Course structure 11 lectures hardware labs 6 workshops 7 sessions, each one 3h, alternate weeks thu. Multiplexer and demultiplexer electrical engineering. Since a multiplexer s job is to select one of the data input lines and send it to the output, it is also known as data selector. In digital electronics, a multiplexer is a combination of logic gates resulting into circuits with two or more inputs data inputs and one output. Browse digikeys inventory of analog switches, multiplexers, demultiplexers4. 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 used to perform highspeed switching and is constructed by electronic components multiplexers are capable of handling both analog and digital applications. They forward the data input to one of the outputs depending on the values of the. Multiplexing is defined as the process of feeding several independent signals to a common load, one at a time. Demultiplexers are mainly used in boolean function generators and. Digital electronics part i combinational and sequential.
As the name implies, their functions are opposite to each other similar to encoder and decoder. Multiplexer and demultiplexer electronics circuits elprocus. These devices are used for sharing a device between two or more applications. Analog switches, multiplexers, demultiplexers analog. A multiplexers mux is a device that allows digital information from several sources to be routed onto a single line. Enables multiple analog signals or digital data streams to be transferred along the same channel over a shared medium. Digital circuitsmultiplexersdemultiplexers wikibooks. The boolean expression for this 1to4 demultiplexer above.
Demultiplexers take one data input and a number of selection inputs, and they have several outputs. As inverse to the mux, demux is a onetomany circuit. It comprehensively covers all the basics of digital electronics, its logic and design. Digital electronics part i combinational and sequential logic.
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