01-04-2011, 03:02 PM
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Synchronous& Asynchronous Multiplexing
• Depending on the need of synchronization between transmitter and receiver, the multiplexing system are classified as
• Synchronous multiplexing.
• Asynchronous multiplexing.
Synchronous multiplexing
• In the synchronous multiplexer, a synchronizing signal is required to be sent alongwith the data.
• For proper operation of synchronous multiplexer, synchronization between the transmitter and receiver is essential.
• In synchronous multiplexing a single clock is used at the transmitter and receiver.The transmitter clock is sent to the receiver which uses the same clock to sample the incoming data as shown in fig.
• One way of sending the clock information to the receiver is to use a separate channel for this purpose.
• If the clock signal is transmitted with the data signal which is continous ‘1’ and ‘0’ for sufficiently long time is detected for to extract the clock signal.
• Example of synchronous multiplexing is TDM.
• Synchronous multiplexing system are complex as compared to asynchronous multiplexing system
Asynchronous Multiplexing
• The asynchronous multiplexes do not need any synchronization between the transmitter and receiver.
• These system are less complicated as compared to the synchronous multiplexers.
• The example of asynchronous multiplexing is FDM.