EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 197)

Analyzing Traces and Events
OTDR 183
Defining a Reference Trace
Defining a Reference Trace
A reference trace is used to compare fibers within the same cable, monitor
fiber deterioration or compare fibers before and after installation. Once a
trace file has been opened, you can define it as the reference trace. The
application will then display it, in red, on the graph.
There is only one reference file open at a time. A trace cannot be a
reference and a main (current) trace at the same time.
A reference trace can be defined in both Advanced and Template modes.
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In Template mode, the reference definition is automatic. To be able to
select Template mode, at least one trace must be already loaded.
Consequently, as soon as you select this mode, the application
automatically sets the loaded trace as the reference.
If several traces are loaded when you select Template mode, the
application will prompt you to identify which file you want to use as a
reference. All other files will be closed (you will be asked to save any
file that has been modified).
In Template mode, you cannot directly remove the reference state
from a file. You will have to switch to Advanced mode to remove it.
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In Advanced mode, the reference definition is manual.