Multiplexing

 Introduction 

Multiplexing is a method of distributing many data transitions over a single network link. this is done by combining an analogue or digital data stream into a single shared signal over the same medium. multiplexing is used as access to the network is a valuable resource and needs to be distributed evenly between the devices attempting to use it. there are many methods of multiplexing each with their own advantages.

 Multiplexing and Demultiplexing 

multiple streams of data can be transformed into a single stream through multiplexing as the signals are combined into a single transmission. Once the transmission has reached its destination the data is retrieved into its original form in the process known as Demultiplexing which is used to reverse the process and effects of Multiplexing.

 Time Division Multiplexing 

Time division multiplexing allocates access to the network in short time periods that rotate between users like a clock. This ensures each devices has equal transmission time but unfortunately this method has redundancies as inactive devices will still be allocated transmission time resulting in blank spaces in the transmission reducing it efficiency. This method is able to work because the cycle rate is so fast that no noticeable delay occurs to users on either end of the transmission.

 Frequency Division Multiplexing 

In frequency division multiplexing multiple analogue signals are transmitted over the same medium in several separate frequencies. this technique is used provide several television channels or radio broadcasts over a single broadcast tower. by separating the signals into distinct frequencies the content of the data is preserved and remains separate from the broadcast that share its transmission.

- Alex Carolan