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Magnum14E Media Converters Installation and User Guide (10/02)
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3.4 Calculating Segment Distances
The media distance considerations are quite different for full-duplex and for half-
duplex (standard Fast Ethernet) installations. Each of these situations are covered below in a
separate section.
3.4.1 Power Budget Calculations for Fiber Media
Receiver Sensitivity and Transmitter Power are the parameters necessary to compute
the power budget. To calculate the power budget of different fiber media installations, the
following equations should be used:
OPB (Optical Power Budget) = P
T
(min) - P
R
(min)
where P
T
= Transmitter Output Power, and P
R
= Receiver Sensitivity
Worst case OPB = OPB - 1dB(for LED aging) - 1dB(for insertion loss)
Worst case distance = {Worst case OPB, in dB} / [Cable Loss, in dB/Km]
where the “Cable Loss” for 62.5/125 and 50/125µm (m.m.) is 2.8 dB/km,
and the “Cable Loss” for 100/140 (multi-mode) is 3.3 dB/km,
and the “Cable Loss” for 9/125 (single-mode) is 0.5 dB/km
The following data has been collected from component manufacturer’s (HP’s and Siemens’)
web sites and catalogs to provide guidance to network designers and installers.