HP 83480A - Q-Factor

The Digital Communications
Analysis Menus
Measure Eye Menu
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Q-factor
This function is only available with the HP 83480A, or if the HP 83480K
option is installed in an HP 54750A.
Q-factor is a gure of merit for an eye diagram indicating the vertical eye
opening relative to the noise at both the high and low logic levels. The
color grade database is used to construct a vertical histogram similar to the
extinction ratio and eye height measurements. The most prevalent P
top
and
P
base
, as well as the data distribution (indicative of noise present) is calculated
from
the
histogram.
Data
is
collected over
the eye
window,
dened in
the
Dene
Measure
menu.
Q
0
f
actor
=
(
P
t
o
p
0
P
b
a
s
e
)
=
(

t
o
p
+

b
a
s
e
)
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
specic
module
.
Key Path 4
Shift
54
Meas eye
5
N
NNNNNNNNNNNNNNNNNNNNNNNNN
Q-factor
6-41