EXFO PSO-200 Optical Modulation Analyzer - Manual (Page 52)

Customizing the Graph and Data Layout
44 PSO-200
Eye Diagrams
I/Q Eye Diagrams
The I (in-phase) and Q (quadrature) eye diagrams represent the “real” and
“imaginary” parts of the complex field as a function of time, respectively.
where t
B
is the remainder after division with the symbol period .
The I eye diagram can be seen as the data visible by looking from the right
of the constellation chart. Similarly with the Q eye diagram by looking from
the top.
Phase Eye Diagram
Eye diagram of arg(E(t
B
)). No amplitude information is provided.
This graph shows the different phases of the signal and the transitions. Its
use is to see the phase shifts in PSK and QAM modulations.
The example below shows four phase levels: /4, 3 /4, -/4, -3/4.
I t
B
( ) Re E t
B
( ) ( ) =
Q t
B
( ) Im E t
B
( ) ( ) =
NRZ-QPSK data
QPSK data