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EXFO FTB-7000 OTDR for FTB-200 v2 User Manual

Page 182

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Analyzing the Results Manually

168

FTB-7000 Series

Getting Event Loss (Four-Point and Least-Square Approximation)

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Four-point event loss: the LSA method is used to fit a straight line to the
backscatter data within the two regions defined by markers a, A and
b, B, that is over the regions to the left and to the right of the event
bordered by markers A and B, respectively.

The two fitted lines are then extrapolated toward the center of the
event and the loss event is directly read from the drop in power
between the two lines.

Four-point
event loss

a

b