User`s guide

C Specifications Definition of Terms / Measurement Conditions
200 E6000C Mini-OTDR User’s Guide, E0302
Event deadzone
The displayed length of a reflective event from the start to
the point where the trace has fallen to 1.5 dB below the
peak.
Conditions: Reflective, lossless event with specified
reflectance, at specified instrument settings.
Group index (of a fiber)
The refractive index of a fiber that corresponds to the
velocity of the modulation content (group velocity) of an
optical wave in a fiber. The group index is typically
slightly higher than the refractive index of the fiber,
because the group velocity is slightly lower than the speed
of light in vacuum divided by the refractive index of the
fiber. Symbol: N.
NOTE The group index setting of the OTDR will influence all
distance measurements.
1.5 dB
Event
Deadzone
Distance