EXFO PSO-200 Optical Modulation Analyzer - Manual (Page 72)

Viewing and Analyzing Results
64 PSO-200
Using Pattern Masks
Using Pattern Masks
You can display masks on graphs to test signal quality and perform a quick
pass/fail verification of signal compliance to applicable standards. Masks
are used to determine whether a sampling point fits in the normal pattern
or not; points considered “in error” can optionally be highlighted in red.
There are three available mask types, as illustrated below:

Intensity mask: consists of upper and lower zones and a center
polygon. Data points and transition points inside these areas are
considered as errors.

Constellation mask: consists of a circular area around each symbol.
Data points outside the circle are considered as errors.

EVM mask: consists of a single polygon area. Data points and transition
points inside the polygon are considered as errors.
Eye EVM mask Eye intensity mask Constellation mask