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Reflective event – EXFO FTB-7000 OTDR for FTB-200 v2 User Manual

Page 316

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Description of Event Types

302

FTB-7000 Series

Reflective Event

Reflective Event

Reflective events appear as spikes in the fiber trace. They are caused by an
abrupt discontinuity in the index of refraction.

³

Reflective events cause a significant portion of the energy initially
launched into the fiber to be reflected back toward the source.

³

Reflective events may indicate the presence of connectors,
mechanical splices, or even poor-quality fusion splices or cracks.

³

Normally, loss and reflectance values are specified for reflective
events.

³

When the reflective spike reaches the maximum level, its top may be
clipped due to the saturation of the detector. As a result, the dead zone
(minimum distance for making a detection or attenuation
measurement between this event and a second nearby) may be
increased.

³

If you set thresholds, the application indicates a reflective fault in the
events table, whenever a value exceeds reflectance or connector loss
thresholds (see Setting Pass/Fail Thresholds on page 53).

Reflected
power (dB)

Distance
(km)

Reflective events

Clipped level