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Launch level – EXFO OTDR 2 User Manual

Page 200

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Description of Event Types

192

OTDR

Launch Level

Launch Level

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

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.

<<<< 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