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
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