Title page for ETD etd-09082012-040517
|Type of Document
||Low frequency cutoff effects in fiber optic communication systems
||Master of Science
|Claus, Richard O.
|Pratt, Timothy J.
|Date of Defense
The presence of low frequency cutoffs in the forward path of the information signal
leads to inter—symbol interference (ISI) and degradation of the signal to noise ratio
at the sampling instant in digital on-off keying (OOK) systems. The low frequency
cutoffs occur as a result of the presence of power separation filters in a line wire
system and gain instability of APD’s to D.C. in fiber optic systems. Also, it is easier
to design amplifiers that do not extend to D.C. The ISI which manifests itself in the
form of baseline wander can cause appreciable degradation in the signal to noise
ratio. This thesis investigates two ways of combating the baseline wander problem.
They are quantized feedback and line coding schemes. A detailed performance evaluation
of quantized feedback scheme is performed. An overview of line coding
schemes is given and some specific codes are evaluated in terms of S/N degradation
at the receiver.
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