EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 209)

Analyzing the Results Manually
OTDR 195
Getting Attenuation (Two-Point and Least-Square Approximation)
To get attenuation:
1. From the main window, go to the Graph tab and press the Measure
button.
2. In the Measurements section, press the Att. button. Markers A and B
appear on the graph.
3. Place markers A and B at any two points on the trace. For more
information, see Using Markers on page 187.
4. Zoom in on the trace and fine-tune the marker positioning if necessary.
For more information, see Using Zoom Controls on page 137.
Note: There should not be any events between markers A and B when
performing the two-point attenuation measurement.
Least-square
approximation Loss over distance
between markers
A and B