VeEX FX150, Руководство пользователя

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OTDR Series e-Manual, RevE00 Page 71 of 128
Use the Refractive Index (IoR) and Backscatter coefficient as
provided by the cable or fiber manufacturer.
•
Thresholds - For information on setting thresholds, see
Section 7.3.1 Thresholds
.
•
Front Panel Check : Tests OTDR connection and displays warning indicating when the
OTDR launch level is 1.5 dB lower than expected or if initial reflectance is too high (-
45dB is default fail threshold). If needed, stop and clean connectors, or proceed with the
bad connection.
For OTDR with built-in internal launch fiber, (G.657), the OTDR connector insertion loss
will depend on the fiber type connected to the test set. Mismatched fibers can result in
higher OTDR connection loss than expected connector loss. Use the SPAN button to
enter fiber mismatch compensation or de-select Include Event Loss . Mismatch fibers
should not impact Reflectance if the correct Fiber type is selected.
Reports Insertion Loss and Reflectance, and also advises if acceptable or not. When
testing PON or xWDM MUX, use a launch fiber between the OTDR and Splitter or MUX
or disable this feature.
When the OTDR is connected to a fiber with traffic (live), a warning is displayed. As long
as the signal exceeds the threshold, the OTDR test will continue. IF the signal is
removed, press OK to resume testing. Pressing Abort will permanently disable the
OTDR test, requiring the need to close the OTDR application and reboot the test set.
•
Show Fiber Sections : Check to show fiber section in the Event table. For other
models, click the Display button to access this option.
•
Auto Zoom Trace: Use this mode to auto scale the viewing window at the end of the
test. For other models, click the
Display
button to access this option.
Disable this feature when using
Realtime
test mode.
•
Distance Unit : Select the distance unit type for fiber length. For other models, click the
Display button to access this option.
7.3.1 Thresholds
Microbends require two different wavelengths. When setting the thresholds,
enter the loss difference between the two wavelengths. The trace will report
when the loss exceeds the macrobend threshold and be displayed in the
LinkMap.
Select the drop-down arrow next to the
A. Thresholds , S. Thresholds , and P/F. Thresholds
fields to select factory default settings ( Default ) or to enter custom settings ( Custom ). Events
will be placed into the table only if the Analysis threshold is met/exceeded. Events that fail to
meet the Pass/Threshold will be flagged and highlighted as red in the event table.