Making Automatic Measurements
Front Panel Measure Section
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Fall Time
Threshold levels (20% to 80%, 10% to 90%, or user-dened) are set in the
Dene Measure menu. The 20% to 80% thresholds are recommended for eye
diagram analysis. Eye diagrams should be measured from the color graded
database:
4
Display
5
,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Color grade
,on.
Key Path
4
Shift
5
N
NNNNNNNNNNNNN
fall
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
Frequency
Frequency
is
1/period
of
the
rst
detected
edge
to the
next
detected
edge
.
K
ey
Path
4
Shift
5
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
Frequency
a
a
a
a
a
a
aa
aa
aa
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa
aa
aa
a
a
a
a
a
a
Overshoot
A histogram is used to characterize signal levels above Vtop. The 95% upper
point of the histogram denes the overshoot level.
Key
Path
4
Shift
5
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
Overshoot
8-7