Multiplexing and (FDM , WDM and TDM) in Computer Network

For the better utilization of bandwidths multiplexing has been introduced . Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link.

Also whenever the bandwidth of a medium linking two devices is greater than the bandwidth needs of the devices, the link can be shared.

There are three basic multiplexing techniques :

• Frequency-Division Multiplexing (FDM)
• Wavelength-Division Multiplexing (WDM)
• Time-Division Multiplexing (TDM)

             -  Synchronous Time-Division Multiplexing
             - Statistical Time-Division Multiplexing

Frequency-Division Multiplexing (FDM)

FDM is an analog technique that can be applied when the bandwidth of a link (in hertz) is greater than the combind bandwidths of the signals to be transmitted.

 FDM is an analog multiplexing technique that combines analog signals.

Example of a demultiplexing process -

Analog Hierarchy

Consider this hierarchical systems which is made up of groups, supergroups, master groups , and jumbo group.

Wavelength Division Multiplexing (WDM)

 To utilize the high data rate capability of fiber-optic cable, WDM has been devised.

WDM is an analog multiplexing technique to combine optical signals.

 

Time Division Multiplexing (TDM)

 TDM is a digital multiplexing technique for combining several low-rate channels into one high-rate one.