Encyclopedia > Intensity modulation

  Article Content

Intensity modulation

Intensity modulation (IM): In optical communications, a form of modulation in which the optical power output of a source is varied in accordance with some characteristic of the modulating signal.

Note: In intensity modulation, there are no discrete upper and lower sidebands in the usually understood sense of these terms, because present optical sources lack sufficient coherence to produce them. The envelope of the modulated optical signal is an analog of the modulating signal in the sense that the instantaneous power of the envelope is an analog of the characteristic of interest in the modulating signal. Recovery of the modulating signal is by direct detection, not heterodyning.

Source: from Federal Standard 1037C and from MIL-STD-188



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
BBC News 24

... cost of running BBC News 24 channel, with so few viewers. Their response was to promote the channel through their ordinary channels BBC1 and BBC2, using terrestrial signals, ...

 
 
 
This page was created in 30.9 ms