frequency division multiple access

1 definition found

frequency division multiple access - Free On-line Dictionary of Computing (26 May 2007) :

  frequency division multiplexing
  FDMA
  frequency division multiple access
  
     <communications> (FDM) The simultaneous transmission of
     multiple separate signals through a shared medium (such as a
     wire, optical fibre, or light beam) by modulating, at the
     transmitter, the separate signals into separable frequency
     bands, and adding those results linearly either before
     transmission or within the medium.  While thus combined, all
     the signals may be amplified, conducted, translated in
     frequency and routed toward a destination as a single signal,
     resulting in economies which are the motivation for
     multiplexing.  Apparatus at the receiver separates the
     multiplexed signals by means of frequency passing or rejecting
     filters, and demodulates the results individually, each in the
     manner appropriate for the modulation scheme used for that
     band or group.
  
     Bands are joined to form groups, and groups may then be joined
     into larger groups; this process may be considered
     recursively, but such technique is common only in large and
     sophisticated systems and is not a necessary part of FDM.
  
     Neither the transmitters nor the receivers need be close to
     each other; ordinary radio, television, and cable service are
     examples of FDM.  It was once the mainstay of the long
     distance telephone system.  The more recently developed time division multiplexing
      in its several forms lends itself to
     the handling of digital data, but the low cost and high
     quality of available FDM equipment, especially that intended
     for television signals, make it a reasonable choice for many
     purposes.
  
     Compare wavelength division multiplexing, time division multiplexing
     , code division multiplexing.
  
     (2001-06-28)