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Encyclopedia > Multiplexer
Schematic of a 2-to-1 Multiplexer. It can be equated to a controlled switch.
Schematic of a 1-to-2 Demultiplexer. Like a multiplexer, it can be equated to a controlled switch.

In electronics, a multiplexer or mux (occasionally the term muldex is also found, for a combination multiplexer-demultiplexer) is a device that performs multiplexing: it selects one of many analog or digital data sources and outputs that source into a single channel. MUX, Mux, or mux can refer to mux, a computer windowing system In circuit design, a multiplexer is often called a mux, MUX, IATA code for Multan International Airport, Pakistan MUX, an electronic musician in Vancouver, Canada Multi-User eXperience, a computer gaming term Marginal rate of substitution variable for... Image File history File links Question_book-3. ... Schematic of a Multiplexer This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Schematic of a Multiplexer This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... This article is about the engineering discipline. ... In telecommunications, multiplexing (also muxing or MUXing) is the combining of two or more information channels onto a common transmission medium using hardware called a multiplexer or (MUX). ...


A demultiplexer (or demux) is a device taking a single input that selects one of many data-output-lines and connects the single input to the selected output line. A multiplexer is often used with a complementary demultiplexer on the receiving end.


An electronic multiplexer functions as multiple-input, single-output switch. A multiplexer has multiple inputs and a selector that connects a specific input to the single output. Miso ) is a traditional Japanese food produced by fermenting rice, barley and/or soybeans, with salt and kōji (the most typical miso is made with soy). ...


The schematic symbol for a multiplexer is an isosceles trapezoid with the longer parallel side containing the input pins and the short parallel side containing the output pin. The schematic on the right shows a 2-to-1 multiplexer on the left and an equivalent switch on the right. The sel wire connects the desired input to the output. An isosceles trapezoid. ...

Multiplex techniques
Circuit mode — for constant bandwidth

TDM | FDM | WDM | Polarization multiplexing | Spatial multiplexing (MIMO) In telecommunications, multiplexing (also muxing or MUXing) is the combining of two or more information channels onto a common transmission medium using hardware called a multiplexer or (MUX). ... In telecommunications, a circuit switching network is one that establishes a dedicated circuit (or channel) between nodes and terminals before the users may communicate. ... Time-division multiplexing (TDM) is a type of digital or (rarely) analog multiplexing in which two or more signals or bit streams are transferred apparently simultaneously as sub-channels in one communication channel, but physically are taking turns on the channel. ... Frequency-division multiplexing (FDM) is a form of signal multiplexing where multiple baseband signals are modulated on different frequency carrier waves and added together to create a composite signal. ... This article or section does not cite its references or sources. ... In electrodynamics, polarization (also spelled polarisation) is the property of electromagnetic waves, such as light, that describes the direction of their transverse electric field. ... Spatial multiplexing is a transmission technique in MIMO wireless communication to transmit independent and separately encoded data signals, so called streams, from each of the multiple transmit antennas. ...

Statistical multiplexing — for variable bandwidth
Packet mode | Dynamic TDM | FHSS | DSSS | OFDMA
Related topics
Channel access methods | Media Access Control
discuss edit

In telecommunications, a multiplexer is a device that performs multiplexing, i.e. that combines multiple analog message signals or digital data streams into one signal. Statistical multiplexing is similar to time-division multiplexing (TDM), except that, rather than arbitrarily assigning a time slot to each signal, each signal is assigned a slot according to priority and need. ... Wikipedia does not yet have an article with this exact name. ... Time division multiple access (TDMA) is a channel access method for shared medium (usually radio) networks. ... Frequency-hopping spread spectrum (FHSS) is a spread-spectrum method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver. ... In telecommunications, direct-sequence spread spectrum (DSSS) is a modulation technique. ... Orthogonal Frequency Division Multiple Access (OFDMA) is a multi-user version of the popular OFDM digital modulation scheme. ... In communications, a channel access method is used to share a communications channel or physical communications medium between multiple users. ... The Media Access Control (MAC) data communication protocol sub-layer, also known as the Medium Access Control, is a part of the data link layer specified in the seven-layer OSI model (layer 2). ... Telecommunication involves the transmission of signals over a distance for the purpose of communication. ... In telecommunications, multiplexing (also muxing or MUXing) is the combining of two or more information channels onto a common transmission medium using hardware called a multiplexer or (MUX). ...


In telecommunications and signal processing, an analog time division multiplexer may take several samples of separate analogue signals and combine them into one pulse amplitude modulated (PAM) wide-band analogue signal. Alternatively, a digital TDM multiplexer may combine a limited number of constant bit rate digital data streams into one data stream of a higher data rate, by forming data frames consisting of one timeslot per channel. Telecommunication involves the transmission of signals over a distance for the purpose of communication. ... Signal processing is the processing, amplification and interpretation of signals, and deals with the analysis and manipulation of signals. ... Time-division multiplexing (TDM) is a type of digital multiplexing in which two or more apparently simultaneous channels are derived from a given frequency spectrum, i. ... Pulse-amplitude modulation, acronym PAM, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. ...


In telecommunications and computer networks, a statistical multiplexer may combine several variable bit rate data streams into one constant bandwidth signal, for example by means of packet mode communication. Telecommunication involves the transmission of signals over a distance for the purpose of communication. ... A computer network is a system for communication among two or more computers. ... A Statistical Multiplexer allows broadcasters to change the bitrate of channels according to the channels needs. ... Wikipedia does not yet have an article with this exact name. ...


An inverse multiplexer may utilize several communication channels for transferring one signal. An inverse multiplexer (often abbreviated to inverse mux, imux or demux) allows a data stream to be broken into multiple lower data rate communications links. ... A Communications channel (or channel for short), models the medium through which information is transmitted from a sender (or transmitter) to a receiver. ...

Contents

Cost savings

The basic function of a multiplexer: combining multiple inputs into a single data stream. On the receiving side, a demultiplexer splits the single data stream into the original multiple signals.
The basic function of a multiplexer: combining multiple inputs into a single data stream. On the receiving side, a demultiplexer splits the single data stream into the original multiple signals.

One use for multiplexers is cost savings by connecting a multiplexer and a demultiplexer (or demux) together over a single channel (by connecting the multiplexer's single output to the demultiplexer's single input). The image to the right demonstrates this. In this case, the cost of implementing separate channels for each data source is more expensive than the cost and inconvenience of providing the multiplexing/demultiplexing functions. In a physical analogy, consider the merging behaviour of commuters crossing a narrow bridge; vehicles will take turns using the few available lanes. Upon reaching the end of the bridge they will separate into separate routes to their destinations. Image File history File links Telephony_multiplexer_system. ... Image File history File links Telephony_multiplexer_system. ... The term multiplexer has uses in several fields of application: Electronics In electronics, a multiplexer or mux is a device that combines several electrical signals into a single signal. ... Analogy is both the cognitive process of transferring information from a particular subject (the analogue or source) to another particular subject (the target), and a linguistic expression corresponding to such a process. ... Commuting is the process of travelling from a place of residence to a place of work. ...


At the receiving end of the data link a complementary demultiplexer is normally required to break single data stream back down into the original streams. In some cases, the far end system may have more functionality than a simple demultiplexer and so, whilst the demultiplexing still exists logically, it may never actually happen physically. This would be typical where a multiplexer serves a number of IP network users and then feeds directly into a router which immediately reads the content of the entire link into its routing processor and then does the demultiplexing in memory from where it will be converted directly into IP packets. This article is about a computer networking device. ...


It is usual to combine a multiplexer and a demultiplexer together into one piece of equipment and simply refer to the whole thing as a "multiplexer". Both pieces of equipment are needed at both ends of a transmission link because most communications systems transmit in both directions. A duplex communication system is a system composed of two connected parties or devices which can communicate with one another in both directions. ...


A real world example is the creation of telemetry for transmission from the computer/instrumentation system of a satellite, space craft or other remote vehicle to a ground system. Telemetry is a technology that allows the remote measurement and reporting of information of interest to the system designer or operator. ...


In analog circuit design, a multiplexer is a special type of analog switch that connects one signal selected from several inputs to a single output.


Digital multiplexers

In digital circuit design, the selector wires are of digital value. In the case of a 2-to-1 multiplexer, a logic value of 0 would connect I0 to the output while a logic value of 1 would connect I1 to the output. In larger multiplexers, the number of selector pins is equal to left lceil log_2(n) right rceil where n is the number of inputs. Digital circuits are electric circuits based on a number of discrete voltage levels. ...


For example, 9 to 16 inputs would require no less than 4 selector pins and 17 to 32 inputs would require no less than 5 selector pins. The binary value expressed on these selector pins determines the selected input pin.


A 2-to-1 multiplexer has a boolean equation where A and B are the two inputs, S is the selector input, and Z is the output: In abstract algebra, a Boolean algebra is an algebraic structure (a collection of elements and operations on them obeying defining axioms) that captures essential properties of both set operations and logic operations. ...

Z = ( A cdot overline{S}) + (B cdot S)
A 2-to-1 mux
A 2-to-1 mux

Which can be expressed as a truth table: Image File history File links Multiplexer_2-to-1. ... Image File history File links Multiplexer_2-to-1. ... Truth tables are a type of mathematical table used in logic to determine whether an expression is true or whether an argument is valid. ...

S A B Z
0 1 1 1
1 0 1
0 1 0
0 0 0
1 1 1 1
1 0 0
0 1 1
0 0 0

This truth table should make it quite clear that when S = 0 then Z = A but when S = 1 then Z = B. A straightforward realization of this 2-to-1 multiplexer would need 2 AND gates, 1 OR gate, and a NOT gate.


Larger multiplexers are also common and, as stated above, requires left lceil log_2(n) right rceil selector pins for n inputs. Other common sizes are 4-to-1, 8-to-1, and 16-to-1. Since digital logic uses binary values, powers of 2 are used (4, 8, 16) to maximally control a number of inputs for the given number of selector inputs.

The boolean equation for a 4-to-1 multiplexer is:

Two realizations for creating a 4-to-1 multiplexer are shown below:

Example: A Single Bit 4-to-1 Line Multiplexer

Image File history File links Multiplexer_Example01. ... Image File history File links Download high-resolution version (490x752, 18 KB) This is a mux realized from 3-state buffers and AND gates. ...

These are two realizations of a 4-to-1 multiplexer:
  • one realized from a decoder, AND gates, and an OR gate
  • one realized from 3-state buffers and AND gates (the AND gates are acting as the decoder)

Note that the subscripts on the In inputs indicate the decimal value of the binary control inputs at which that input is let through.
A Digitrax DH163AT DCC decoder in an Athearn locomotive before the shell goes on. ... Media:Example. ... // Function The OR gate is a digital logic gate that behaves according to the truth table to the right. ... In digital circuits, a tri-state or three state buffer is used to allow multiple logic gates to drive the same output, usually a bus. ...

Chaining multiplexers

Larger multiplexers can be constructed by using smaller multiplexers by chaining them together. For example, an 8-to-1 multiplexer can be made with two 4-to-1 and one 2-to-1 multiplexers. The two 4-to-1 multiplexer outputs are fed into the 2-to-1 with the selector pins on the 4-to-1's put in parallel giving a total number of selector inputs to 3, which is equivalent to an 8-to-1.


List of ICs which provide multiplexing

The 7400 series has several ICs that contain multiplexer(s): The 7400 chip, containing four NANDs. ...

S.No. IC No. Function Output State
1 74157 Quad- 2:1 MUX Output same as input given
2 74158 Quad- 2:1 MUX Output is inverted input
3 74153 Dual- 4:1 MUX Output same as input
4 74352 Dual- 4:1 MUX Output is inverted input
5 74151A 8:1 MUX Both outputs available ie. Complementary outputs
6 74152 8:1 MUX Output is inverted input
7 74150 16:1 MUX Output is inverted input

Digital demultiplexers

Demultiplexers take one data input and a number of selection inputs, and they have several outputs. They forward the data input to one of the outputs depending on the values of the selection inputs. Demultiplexers are sometimes convenient for designing general purpose logic, because if the demultiplexer's input is always true, the demultiplexer acts as a decoder. This means that any function of the selection bits can be constructed by logically OR-ing the correct set of outputs. A Digitrax DH163AT DCC decoder in an Athearn locomotive before the shell goes on. ...

Example: A Single Bit 1-to-4 Line Demultiplexer


Image File history File links Demultiplexer_Example01. ... Image File history File links Demultiplexer_Example01. ...


List of ICs which provide demultiplexing

The 7400 series has several ICs that contain demultiplexer(s): The 7400 chip, containing four NANDs. ...

S.No. IC No. Function Output State
1 74139 Dual- 1:4 DEMUX Output is inverted input
2 74155 Dual- 1:4 DEMUX Complementary outputs available
3 74156 Dual- 1:4 DEMUX Output is open collector
4 74138 1:8 DEMUX Output is inverted input
5 74154 1:16 DEMUX Output is same as input
6 74159 1:16 DEMUX Output is open collector and same as input

This page is a candidate for speedy deletion, because: Non-informative cut-paste If you disagree with its speedy deletion, please explain why on its talk page or at Wikipedia:Speedy deletions. ...

See also

Look up multiplexer, demultiplexer in Wiktionary, the free dictionary.

  Results from FactBites:
 
The Two-Input Multiplexer (526 words)
The multiplexer circuit is typically used to combine two or more digital signals onto a single line, by placing them there at different times.
This is not as difficult as it may seem at first glance; the telephone network combines multiple audio signals onto a single pair of wires using exactly this technique, and is readily able to separate many telephone conversations so that everyone's voice goes only to the intended recipient.
A set of multiplexers is used to first select the row address to the memory, then switch to the column address.
Current Multiplexer (224 words)
The DRA-CSM-1 Current Multiplexer is a solid state multiplexer capable of transferring the selected 4-20 mA input current signal to the output terminals in less than 10 microseconds at an accuracy better than 0.01%.
The channel selected by the multiplexer is directed to the control device’s (e.g., PLC’s) analog inputs.
Power is maintained by the multiplexer to the unselected channels thereby maintaining uninterrupted transmitter current flow.
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