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What is the difference between multiplexing and demultiplexing?
MODULATION: Usually, the signal that we want to transmit, say a speech signal with 4000 Hz frequency, will require a very big antenna. For any signal the frequency… f is related to wavelength L as c = L * f ………………………… (i) Where c is velocity of light. And antenna length is generally taken as L/2 which simply means for our case antenna length is 75000 m, obviously this size of antenna is too big to use on day to day basis. That is why we take our speech signal or the desired signal and take another high frequency signal known as carrier (carrier can be any signal but should have high frequency and in practice we use a simple continuous wave signal), now we alter one or more parameters of this career signal in accordance with our desired signal, this parameters can be any one or combination of parameters. The basic parameters are amplitude, frequency, and phase of the signal. The result of this alteration we get is known as modulated signal, the desired signal which we wanted to transmit is known as modulating signal also known as base band signal and modulated signal is also known as band pass signal. The whole process is known as MODULATION. There are many types of modulation starting from amplitude modulation popularly known as AM, frequency modulation (FM), QPSK, PCM, GMSK, QAM etc. MULTIPLEXING: Basically there are two types of system, time domain and frequency domain. In time domain we transmit frames, and in frequency domain we transmit in accordance with frequency. Now if there is more than one source of signal and we want to transmit them together then we implement multiplexing. In multiplexing we mix the source signals (off course with some precautions) say if we want to mix them in time domain then our frame will contain some packets form source A and some packets from source B and so on depending upon the constraints of the channel and time frame. The signals that source are generating can either be modulated signals or we can even send our multiplexed signal to the modulator and then modulate the signal. At the receiving end be demultiplex the signals. In multiplexing we do not provide a dedicated resource to a single source. I.e. we do not dedicate the complete time frame to a single source (in our case it is time frame). Multiplexing is also seen as you are travelling on a four lane road and suddenly it get narrower and turned to single lane, at this point the traffic police will allow one car from each lane to drive through that narrow single lane, this is what we called MULTIPLEXING. MULTIPLE ACCESS: As the name suggest, multiple access means multiple users can access the channel or link. Multiple access provides dedicated resources to the user (with a time constraint) in comparison to the multiplexing which does not provide any type of resources. There are many type of Multiple access schemes like FDMA frequency division multiple access, TDMA time division multiple access, CDMA code division multiple access, SDMA space division multiple access etc. take the example of FDMA, the whole frequency band is divided into small frequency bands called channels, now each channel is having certain capacity to take the traffic say a channel can accommodate single user at time, then the whole frequency bandwidth can be access by as many users as there are channels, mathematically if we are having a bandwidth of 200 KHz and channel bandwidth is 50 KHz then it means we can accommodate 4 users at a time by giving 50 KHz channel to each. This is so called multiple access, i.e. multiple users can access the bandwidth simultaneously and we do not require any additional hardware at the receiving end to separate the desired user from the other users as we do in Multiplexing. In reality the concept of Multiple Access is more complicated and In GSM each channel can accommodate 8 users at a time and each channel has 200 KHz bandwidth. Even I am searching its answer. But, I feel, multiplexing is technique and multiple access is way to use this technique. but there is a difference between multiple access and multiplexing that should be noted: Multiple access refers to the remote sharing of a communication channel such as a satellite or radio channel by users in highly dispersed loctions. on the other hand, multiplexing refers to the sharing of a channel such as a telephone channel by users confined to a local site. Modern telephone networks allow bandwidths in their channels that are much larger than those is needed for a digitalized telephone channel. Basically, a number of channels share a common transmission medium with the aim of reducing costs and complexity in the network. Multiplexing is defined as the process by which several signals from different channels share a channel with greater capacity. When the sharing is carried out with respect to a remote resource, such as a satellite, this is referred to as multiple access rather than multiplexing. According to the definition described in Encyclopedia of Britinica : Multiplexing is defined as the sharing of a communications channel through local combining at a common point. In many cases, however, the communications channel must be efficiently shared among many users that are geographically distributed and that sporadically attempt to communicate at random points in time. Three schemes have been devised for efficient sharing of a single channel.
A multiplexer takes many inputs and and selectively allow one output. A demultiiplexer is just the opposite function
An encoder refers to a device that is used to change a signal or data into a code. Whereas a Multiplexer or mux is a device which performs multiplexing or it takes information… from more than one channels and outputs into a single channel. Thus a multiplexer is basically a kind of encoder where its function is to combine multiple inputs into one output.
Multiplexing-Combining all the inputs into one output. Switching-Taking one input to the output, at a time/frequency
A multiplexor is a device that takes two or more signals and encodes them on fewer (often, on one) wire. A demultiplexor is a device that reverse that process.
A decoder takes n inputs and produces 2^n outputs. An encoder takes 2^n inputs and produces n outputs. A multiplexer selects one line from many lines. The inverse of s…election is distribution. A demux essentially transmits data from one line line to 2^n possible output lines. The output line is determined by n select lines. In short, a multiplexer selects an input line, a demultiplexer selects an output line. The differences between these two circuits is subtle, as far as I can tell. A demux simply selects an output line, nothing more. It's a glorified switch. A decoder takes n inputs, and uses those inputs to determine which of the 2^n output lines is high. This is the difference, I think. A decoder is designed to simply keep one line high. A demux is designed to set one output equal to the input (whether it be high, low, or a changing signal).
In multiplexed system n-lines (channels) share bandwidth of one link
what is the difference between PCR simplex and multiplex
multiplexer combines several individual signals into a single signal.demultiplexer separates a single signal into several individual signals. There are many types of multiplex…ing, a few are: time domain multiplexingfrequency domain multiplexingdigitally coded multiplexingetc.
Segmentation is the division of packets across the network for example from Location A to location B , and multi plexing is the interleaving of pieces when transversing trough… different media
upward and downward ultiplexing
Multiplexer used to direct one input to many out put. But decoder is used to convert one code form to another code (e.g. binary to gray) depends on design.
Decoder convert an input binary code into a corresponding single active output. you can think of a Multiplexer (switch) as your home systems-it connects data from one of n so…urces to its output.when you want play movie you select movie on your home system then it switch it to movie..
Definition: Multiplexing is the process of combining 2 or more signals together into one multi-component signal with all signals being sent to the same receiver or… receivers. Demultiplexing is the process of separating the multiplexed signal into its individual component signals. NOTE: The major distinction between multiplexing and multiple access is that in multiple access the signals are coming from many different sources and are going to many different destinations. Multiplexing is used to describe cases in which there is only one source and one destination for the many individual signals.
A multiplexer, commonly referred as an input selector, is a circuit with many inputs but only one output: it has some data inputs, control inputs and one output, depending… on the control inputs, one input from the data inputs is sent to the output .A demultiplexer is a circuit with one data input, few control inputs and many outputs, it is also known as output selector.
Modulation is the way a source of information transmits that information through a carrier. For example, look at human speech. A person, the source of information, transmits… data by modulating the air with sound waves in a way that is understandable to other humans. In this case the air is the carrier. Multiplexing is when many slower data lines (CAT5, POTS, etc.) are combined into a single faster data line (T1, Optical Fiber). An example is the communications backbone between two cities. A fast, high bandwidth optical line joins the cities together, but when it reaches either city's limits, it is split up into many individual phone or data circuits. The bottom line is that modulation is how a source manipulates the carrier where as multiplexing is combining multiple circuits into a single, faster line and then separating them again.
The data bus and the low order address bus on the 8085 microprocessor are multiplexed with each other. This allows 8 pins to be used where 16 would normally be required.… The hardware interface is required to demultiplex the bus by latching the low order address in the first T cycle, on the falling edge of ALE.