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Launch level – EXFO FTB-7000 OTDR for FTB-200 v2 User Manual

Page 318

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Description of Event Types

304

FTB-7000 Series

Launch Level

Launch Level

This event indicates the level of the signal launched into the fiber.

³

The figure above shows how the launch level is measured.

A straight line is plotted using least-square approximation to fit all trace
points in the linear area between the first and second detected events.

The straight line is projected toward the Y-axis (dB) until it crosses the
axis.

The crossing point indicates the launch level.

³

<<<< in the events table indicates that the launch level is too low.

Reflected power
(dB)

Distance
(km)

Launch level
event position

Second event

Launch

level

Linear area