Multiplexer
In communication field, the methods by which many inputs (the inputs may be analog or digital in form) are combined together to give one output is known as multiplexing. Multiplexing is a technique to select one suitable output from the given number of input lines . Another terminology in multiplexers are the section lines. The output is determined with the help of selection lines .
The selection lines are dependent on the type of multiplexer. There are various types of multiplexer namely
For example: We use frequency division multiplexing for cable television ,voice telephony requirements etc. time division multiplexing or time division multiple access(TDMA) for 2G and 3G systems. Whereas, in prior versions of 2G, known as code division multiple access(CDMA), we were using code division multiplexing.
Uses of Frequency Division Multiplexing (FDM)
When the total bandwidth or frequency available is divided into a set of frequency which should be non-overlapping, this technique is known as frequency division multiplexing (FDM). Each subset is used to carry different signals. This allows the common medium to be shared by many different frequencies. You all must be watching television as a daily part of your life which works with the help of cable wire, it is the most extensive and common example of frequency division multiplexing in real life. The television channels which are nothing but frequencies are carried by one single cable which is the medium.
Uses of Time Division Multiplexing (TDM)
When the message to be sent is differentiated with a very short time lag or when the packets to be sent takes turn on the channel such as one packet is transmitted during the time slot 1 , the second is transmitted at slot 2 and so on. This technique of transmitting and receiving of the data while taking turns on the time is known as Time Division Multiplexing.
This type of multiplexing is mainly used in telephone networks like in circuit switch networks namely public switch telephone network (also known as landline) in which there are multiple subscribers, and if all the lines are full at a particular time then we are not able to make the call. But if we try after some time our call gets connected!! This is mainly because during the time one or more subscriber hangs the phone creating the vacancy of the medium at that time.
Uses of Code Division Multiple Access (CDMA)
This is a technique in which several users are successfully able to transmit and receive the data simultaneously that is at the same time over the same frequency. So in contrast to FDM and TDMA which divides access by frequency (wavelength) or time respectively, code division multiple access is spread spectrum signaling.
For example: Many people speaking in a room can hear and understand your particular language and all other languages are considered as noise. In the same way in CDMA, each user is given a code, in a single channel there are many codes but the users who are connected to the similar code only can communicate.
This code is used in the GPS systems and signaling for mobile networks.
Demultiplexer
In electronics, a demultiplexer is a device which takes the output from a single line and directs it to several output lines. It is used when we need to send the same output to several lines or to several devices. Mainly demultiplexer is required to break the single data stream to the original data streams.
Also, the main aim of a demultiplexer is to combine the data and to transmit it over the medium by taking in single input and making the information to exit through multiple outputs.
Note: We are in process of finding more uses for Demultiplexer, if you happen to know more than please add the info in the comments and help your co-students!
In communication field, the methods by which many inputs (the inputs may be analog or digital in form) are combined together to give one output is known as multiplexing. Multiplexing is a technique to select one suitable output from the given number of input lines . Another terminology in multiplexers are the section lines. The output is determined with the help of selection lines .
The selection lines are dependent on the type of multiplexer. There are various types of multiplexer namely
- 2-to-1 multiplexer(having 1 selection line)
- 4-to-1 multiplexer(having 2 selection lines)
- 8-to-1 multiplexer(having 3 selection lines)
- 16-to-1 multiplexer(having 4 selection lines).
For example: We use frequency division multiplexing for cable television ,voice telephony requirements etc. time division multiplexing or time division multiple access(TDMA) for 2G and 3G systems. Whereas, in prior versions of 2G, known as code division multiple access(CDMA), we were using code division multiplexing.
Uses of Frequency Division Multiplexing (FDM)
When the total bandwidth or frequency available is divided into a set of frequency which should be non-overlapping, this technique is known as frequency division multiplexing (FDM). Each subset is used to carry different signals. This allows the common medium to be shared by many different frequencies. You all must be watching television as a daily part of your life which works with the help of cable wire, it is the most extensive and common example of frequency division multiplexing in real life. The television channels which are nothing but frequencies are carried by one single cable which is the medium.
Uses of Time Division Multiplexing (TDM)
When the message to be sent is differentiated with a very short time lag or when the packets to be sent takes turn on the channel such as one packet is transmitted during the time slot 1 , the second is transmitted at slot 2 and so on. This technique of transmitting and receiving of the data while taking turns on the time is known as Time Division Multiplexing.
This type of multiplexing is mainly used in telephone networks like in circuit switch networks namely public switch telephone network (also known as landline) in which there are multiple subscribers, and if all the lines are full at a particular time then we are not able to make the call. But if we try after some time our call gets connected!! This is mainly because during the time one or more subscriber hangs the phone creating the vacancy of the medium at that time.
Uses of Code Division Multiple Access (CDMA)
This is a technique in which several users are successfully able to transmit and receive the data simultaneously that is at the same time over the same frequency. So in contrast to FDM and TDMA which divides access by frequency (wavelength) or time respectively, code division multiple access is spread spectrum signaling.
For example: Many people speaking in a room can hear and understand your particular language and all other languages are considered as noise. In the same way in CDMA, each user is given a code, in a single channel there are many codes but the users who are connected to the similar code only can communicate.
This code is used in the GPS systems and signaling for mobile networks.
Demultiplexer
In electronics, a demultiplexer is a device which takes the output from a single line and directs it to several output lines. It is used when we need to send the same output to several lines or to several devices. Mainly demultiplexer is required to break the single data stream to the original data streams.
Also, the main aim of a demultiplexer is to combine the data and to transmit it over the medium by taking in single input and making the information to exit through multiple outputs.
Note: We are in process of finding more uses for Demultiplexer, if you happen to know more than please add the info in the comments and help your co-students!
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