HP 83480A - Measuring Duty Cycle Distortion

Eye, Mask and Eyeline Mode Measurement Tutorials
Making Eye Diagram Measurements
Measuring duty cycle distortion
Duty cycle distortion is a measurement of the time separation of the rising
and falling edge of the eye at the center threshold level. The default
center value is 50%, and can be changed in the 4
Dene meas
5 menu. Narrow
horizontal histograms are computed at the center threshold level to determine
the mean location of the rising and falling edge at that level. The time
dierence between the falling and rising edge can be expressed in absolute
time:
D
C
D
time
=
j
T
r
ise
center
0
T
f
al
l
center
j
The time
dierence between
the falling
and
rising
edge
,
expressed
as
a
percentage of
the bit
period:
D
CD
per
cent
=
j
T
r
ise
center
0
T
f
al
l
center
j
bit
per
iod
Figure 5-8. Duty cycle distortion measurement.
5-17