HP 83480A User Manual

Eye, Mask and Eyeline Mode Measurement Tutorials
Making Eye Diagram Measurements
Measuring fall time
The falling edge of a pulse is dened as a transition that passes through
the upper, middle, and lower threshold or logic levels.For an edge to be
measured, it must complete the transition through all three threshold
levels. Once a falling transition has been determined, the fall time may be
determined by the following:
(time at the lower threshold crossing) 0 (time at the upper threshold
crossing) = Fall time
The instrument
has two
standard and
a
user-dened
threshold
level
for
which
fall time
may be
measured. The
rst
is
the
10%
to
the
90%
point
on
the
transition, and
the second
is
the
20%
to
the
80%
point
on
the
transition.
The
20%
to
80%
transition
is
recommended
for
devices with
signicant pulse
distortion.
Using
the
user-dened
threshold
levels
,
any
point on
the transition
may
be
chosen.
The
measurement
threshold
can
be
changed
by
using
the
4
Dene
meas
5
menu.
Figure 5-11. Fall time measurement.
5-23

HP 83480A Specifications

General

Brand	HP
Model	83480A
Category	Measuring Instruments
Language	English