EXFO FTB-700 for FTB-1 - Manual (Page 258)

Analyzing Traces with the Bidirectional Analysis Application (Optional)
250 FTB-700 Series
Modifying Trace Analysis Settings
Modifying Trace Analysis Settings
You can view the current trace parameters for the bidirectional
measurement as well as for the A->B and B->A traces (see Trace Info. Tab
on page 210). However, you can only modify the analysis settings for the
current A->B and B->A traces, not for the bidirectional measurement.
Two groups of parameters can be changed:

The fiber settings:

IOR: Index of refraction of the displayed trace, also known as
group index. If you modify this parameter, the distance
measurements for the trace will be adjusted. You can enter an IOR
value directly or let the application calculate it with the distance
between span start and span end you provide.

Backscatter: Rayleigh backscatter (RBS) coefficient of the
displayed trace. If you modify this parameter, the reflectance and
ORL measurements for the trace will be adjusted.

Helix factor: Helix factor setting of the displayed trace. If you
modify this parameter, the distance measurements for the trace
will be adjusted.