HP 83480A - Crossing %

The Digital Communications
Analysis Menus
Measure Eye Menu
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Crossing %
Crossing percentage is a measure of the location of the eye crossing points
relative to the separation between V
top
and V
base
. Typically, it is desirable to
have the crossing points located midway between V
top
and V
base
.Inthiscase
the crossing percentage would be 50% according to the following formula:
C rossing per cent =100

V
cr oss
0 V
base
V
top
0 V
base

V
top
and
V
base
are
calculated
from
a
histogram
using
data within
the eye
window
as
dened
in
the
Dene
Measure menu.
V
cross
is
the
most
prevalent
vertical
location
or
amplitude
of
the
crossing
points
.
A
horizontal
histogram
over
the
entire
display
is
used
to
determine
the
time
location
of
the
crossing
points
.
Narrow
vertical
histograms
are
then
used
to
determine
the
vertical
location
of
V
cross
.
K
ey
Path
4
Shift
5
4
Meas
ey
e
5
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Crossing
%
6-36