Multiplexing Categories

™   Categories of Multiplexing

FDM o    An analog technique that can be applied when BW of the link is greater than the combined BW of the signals to be TX o    Signals generated by each sending device modulate difference carrier frequencies o    These  modulated  signals  are  then  combined  into  a  single  Composite  signal  that can be transported by the link o    Carrier frequencies are separated by enough BW to accommodate the modulated signal o    These BW ranges are the channels through which the various signals travel FDM (Guard Bands) •GUARD BANDS: Channels must be separated by strips of unused BW   (guard bands) to prevent signals from Overlapping o    In fig. the TX path is divided into 3 parts, each representing a channel to carry one TX o    As  an  analogy,  imagine  a  point  where  3  narrow  streets  merge  to  form  a  3-lane highway o    Each of these streets correspond to a lane of the highway o    Each car merging on to the highway from one of these streets still has its own lane and can travel w/o interfering with cars from other lanes