EXFO FTB-800 Series for FTB-1 - Manual (Page 328)

Test Results
318 FTB-700G/800 Series
PTP Stats
IPDV
Inter Packet Delay Variation (IPDV) is available for Sync and Delay Req
messages and is measured for all valid in-sequence messages (see Delay
Measurement on page 342). Current, Average, Minimum, Maximum, and
Standard Deviation measurement values are displayed. The Standard
Derivation is the measure of the dispersion of messages from its mean.
When a value is below 1μ second, “< 1μs” is displayed. The pass/fail
verdict is also displayed beside the maximum value when enabled.