R
IGOL
T
ECHNOLOGIES USA
I
NC
877-4-RIGOL-1 How-To
Guide
www.rigolna.com
The
FFT
can
be
displayed
full
screen
with
the
channel
as
well
by
adjusting
the
WINDOW
setting.
However,
you
like
to
view
it
take
notice
of
the
separate
VERT/div
and
HORIZ/div
settings
shown
in
purple.
You
can
adjust
these
by
pushing
the
MATH
button
and
then
using
the
horizontal
and
vertical
scale
knobs.
If
the
FFT
isn’t
shown
on
the
screen,
move
the
VERTICAL
position
knob
until
you
see
the
zero
point
and
then
the
signal.
There
are
two
options
for
vertical
units
on
the
FFT:
mVrms
and
dBVrms.
When
looking
to
view
small
signals
along
with
much
larger
signals
dBVrms
is
beneficial
because
it
provides
a
log
scale.
For
those
not
used
to
logarithmic
scaling
look
at
the
screenshot
above.
In
the
split
screen
mode
shown
there
are
8
vertical
divisions
dedicated
to
the
FFT.
Here
are
the
values
at
the
top
of
each
division
given
the
200
mVrms/div
setting
and
the
position
of
the
zero
marker
on
the
left
at
the
top
of
the
bottom
division:
Divisions
down
from
top
of
FFT
screen
Value
at
top
of
that
division
0
(top
of
purple
display)
1.4
Vrms
1
1.2
Vrms
2
1
Vrms
3
800
mVrms
4
600
mVrms
5
400
mVrms
6
200
mVrms
7
0
mVrms
8
(very
bottom
of
the
screen)
‐
200
(negative
numbers
are
not
used
by
a
mVrms
scale)
So,
in
this
mode
the
FFT
has
about
1.4
Vrms
of
total
range
capability.
You
can
change
the
sensitivity,
but
if
you
wanted
to
see
a
10
Vrms
fundamental
and
a
10
mVrms
harmonic
at
the
same
time
it
isn’t
possible
on
a
linear
scale.
