Heathkit IG-4505 - Page 36

Page 36
jo a am om aoa pene
Tr
DISPLAY
Figure 2-3
You
can
also
use
the
calibrator
to
measure
the
rise
time
of
most
oscilloscopes
as
shown
in
Figure
2-3.
Rise
time
Tr
is
defined
as
the
time
required
for
the
trace
to
move
from
10%
to
90%
of
the
total
waveform.
This
measurement
is
usually
made
with
the
1
ys
(1
MHz)
signal
from
the
calibrator
and
the
fastest
sweep
speed
of
your
oscillosopce
(including
any
sweep
magnifier
if
it
has
this
feature).
However,
if
your
oscilloscope
has
sufficient
bandwidth
~
35
MHz
(where
the
rise
time
is
less
than
10
ns),
the
inherent
rise
time
of
the
calibrator
signal
becomes
a
significant
factor.
In
which
case
you
should
use
the
formula
Tr
scope
=/(Tr
display)*
—
(4
ns)*.
The
4
ns
is
the
rise
time
of
the
calibrator
signal.
The
bandwidth
of
most
oscilloscopes
can
be
determined
from
the
formula
BW
© =
.35
Tr
where
BW
is
expressed
in
MHz
and
Tr
is
expressed
in
ns.
NOTE:
When
you
make
rise
time
measurements,
always
keep
the
vertical
attenuator
in
its
calibrated
position.
Otherwise,
the
measurement
may
not
be
accurate.