In many
applications,
the
details
of a
pulse's
shape
are
important.
Pulses
can
become
distorted
and
cause a
digital
circuit
to
malfunction,
and the
timing
of
pulses
in a
pulse
train is
often
significant.
Standard
pulse
measurements
are
pulse
width
and
pulse
rise
time.
Rise
time is
the
amount
of time
a pulse
takes to
go from
the low
to high
voltage.
By
convention,
the rise
time is
measured
from 10%
to 90%
of the
full
voltage
of the
pulse.
This
eliminates
any
irregularities
at the
pulse's
transition
corners.
This
also
explains
why most
oscilloscopes
have 10%
and 90%
markings
on their
screen.
Pulse
width is
the
amount
of time
the
pulse
takes to
go from
low to
high and
back to
low
again.
By
convention,
the
pulse
width is
measured
at 50%
of full
voltage.
See
Figure
below
for
these
measurement
points.
Rise
Time and
Pulse
Width
Measurement
Points
Pulse
measurements
often
require
fine-tuning
the
triggering.
To
become
an
expert
at
capturing
pulses,
you
should
learn
how to
use
trigger
holdoff
and how
to set
the
digital
oscilloscope
to
capture
pretrigger
data, as
described
earlier
in the
Controls
section.
Horizontal
magnification
is
another
useful
feature
for
measuring
pulses,
since it
allows
you to
see fine
details
of a
fast
pulse.
