EXFO FTB-7000 OTDR for FTB-200 v2 - Manual (Page 169)

Analyzing Traces and Events
OTDR 155
Enabling or Disabling the Detection of Reflective Ends of Fiber
The table below shows the differences you will notice in the event table
depending on if you enable the detection of reflective ends of fiber or not.
Option not selected
(conventional analysis)
Option selected
Case
Event on which
span end is set
Loss or
reflectance value
Event on
which span
end is set
Loss or
reflectance
value
Span end
located on a
physical event
that crosses the
end-of-fiber
(EoF) threshold
Non-reflective
fault or
reflective fault
Value as
calculated by the
conventional
analysis
Same as the
conventional
analysis
Same as the
conventional
analysis
Span end
located on a
physical event
whose loss is
below the EoF
threshold
Non-reflective
fault or
reflective fault
Value as
calculated by the
conventional
analysis
If applicable,
reflective fault
(located in
the “noisy”
area)
a
a. The cumulative loss value will remain the same for all elements appearing after the event on which the
span end was set according to the conventional analysis. The span loss value (Trace Info. tab) will
correspond to the loss calculated between span start and the event on which the span end was set
according to the conventional analysis.
If applicable,
reflectance value
as calculated by
the conventional
analysis.
b
b. Value is underestimated because the event is located in the “noisy” area.
Span end not
located on any
physical event
End of analysis N/A If applicable,
reflective fault
(located in
the “noisy”
area)
c,d
c. The end-of-analysis event is replaced by a non-reflective event with a loss value of 0 dB.
d. The cumulative loss value will remain the same for all elements appearing after the inserted event. The
span loss value (Trace Info. tab) will correspond to the loss calculated between span start and the
inserted event.
If applicable,
reflectance value
as calculated by
the conventional
analysis.
b