HP 83480A User Manual

Increasing Measurement Accuracy
and Time-Interval Measurement
Time-Interval Measurements
Rise time response
If a step with a Gaussian shape is applied to the input of the instrument,
the measured 10 percent to 90 percent rise time is approximately equal to
the quadrature sum of the rise time of the step and the rise time of the
instrument. The rise time of the instrument depends on which plug-in is
used.
Consider measuring the rise time of a signal that has an actual rise time of
1ns. If you use an instrument and probe that have a combined rise time of
1ns
,the
error
will
be
approximately
40
percent:
M
easured
r ise
time =
p
(1
ns )
2
+
(1 ns
)
2
=
1 :
41 ns
If
instead
you
measure
the
same
signal
with
an
instrument and
probe with
a
combined
rise
time
of
330
ps
,
the
error will
be reduced
to
approximately
5
percent:
M
easur
ed
r
ise
time
=
p
1
ns
)
2
+
(330
ps
)
2
=
1
:
05
ns
T
able
9-1
shows
the
error
for
other
ratios
of
instrument
rise
time
to
signal
rise
time
.
T
able
9-1.
Rise-Time Measurement
Errors
Signal
Rise
Time/
Instrument
Rise
Time
Measurement
Error
%
1 40
2 12
3 5
4 3
5 2
6 1.4
7 1
You can apply the concepts of rise time measurement to measuring the
interval between two identical edges at dierent levels
. The error in
9-15

HP 83480A Specifications

General

Brand	HP
Model	83480A
Category	Measuring Instruments
Language	English