GarrettCom 14E manual Calculating Segment Distances, Power Budget Calculations for Fiber Media

Magnum14E Media Converters Installation and User Guide (10/02)

3.4Calculating 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.

3.4.1Power 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) = PT(min) - PR(min)

where PT = Transmitter Output Power, and PR = 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 50/125∝m (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.

www . GarrettCom . com

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