EXFO FTB-5600 Distributed PMD Analyzer - Manual (Page 48)

Setting up and Operating your Distributed PMD Analyzer
42 FTB-5600
Performing an Acquisition
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The sensitivity parameter sets the electronic APD gain. You should use
the high setting unless you are interested only in the very beginning of
the link. The sensitivity of the measurement is dependant on the PMD
range. A greater sensitivity increases the number of averages and will
take longer to be achieved. Consider the following to improve your
dynamic range.
Note: You can obtain the dynamic range of the trace by subtracting the
backscatter level at the fiber end from the injection level accepted range
value.
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The PMD resolution is the minimum value to be measured. EXFO
recommends setting this value to the lowest value of interest for your
testing purposes. A smaller PMD resolution signifies a larger number of
PMD steps and increases acquisition time.
Sensitivity Number of Averages to Select
Low 500
Medium 1000
High 2000
Difference between
injection and OTDR
trace level where
the PMD curve ends