EXFO PSO-200 Optical Modulation Analyzer - Manual (Page 271)

Measurement Definitions
Optical Modulation Analyzer 263
Measurements for Eye Diagrams
Rise Time and Fall Time

Rise time: delay between the times where the slope transits through
the 20 % and up to the 80 % thresholds.

Fall time: delay between the transit times through the 80 % level down
to the 20 % level.
Note: The 20-80 % thresholds can be changed in the Optical Modulation Analyzer
application (see Setting Analysis Parameters on page 22).
Rise and fall time are applied to the magnitude of the signal for RZ formats.
Rise time
Rise time
Magnit
ude
In-
pha
se/Quad
rature
p
hase