EXFO FTB-5600 Distributed PMD Analyzer - Manual (Page 124)

Acquisition Data
118 FTB-5600
In the FTB-5600, P-OTDR traces are acquired in pairs for two
closely-spaced optical frequencies, ν
k
±½δν with the same I/O-SOP. The
central frequency ν
k
of each pair is in general different than that of any
other pair. Although the I/O-SOP corresponding to traces within each pair
must be the same, they are generally different from one pair to another.
This overall process is shown in the figure below:
Note: Each P instance represents an OTDR trace.
In order to settle up an acquisition, you will note that since the acquisition
consist of OTDR traces, you must set the OTDR trace parameters such as
the range, pulse and number of averages. For the PMD part, you must set
the number of SOPs, the frequency range, and the frequency steps
(through the PMD scale and the residual PMD).
In the example above, each SOP is build from eight OTDR traces. If you
take another example of an acquisition of of 100 SOPs and 3 steps, plus the
intermediate data, would result in 2400 OTDR traces
(3 steps x 8 traces x 100 SOPs).