Eye, Mask and Eyeline Mode Measurement Tutorials
Making Eye Diagram Measurements
Measuring Q-factor
For HP 83480A only
Q-factor provides a gure of merit for an eye, indicating the opening of the
eye relative to the noise present on the eye. The measurement data used is
similar to that discussed for eye height.
Q
0
f actor
=(
P
top
0
P
base
)
=
(
top
+
base
)
N
O
T
E
The
measured
values
of
top
and
base
will
include
the
HP
83480A
channel
noise.
Channel noise
ma
y
be
larger
than
the
signal
noise
,
resulting
in
a
Q-factor
less
than
the theoretical
value.
F
or
typical
channel noise
gures,
refer
to
the
documentation
for
the
specic
module
.
5-19