HP 8753D - Page 274

frequency
domain data
just before
the transform.
(A
special
transform
mode
is
available
to
\demodulate" CW
sweep
data,
with
time
as
the
stimulus
parameter
,
and
display
spectral
information
with frequency
as
the
stimulus
parameter
.)
F
ormat
This
operation converts
the complex
number
pairs
into
a
scalar
representation
for
display
,
according
to
the
selected
format.
This
includes
group
delay
calculations
.
These
formats
are
often
easier
to
interpret
than
the
complex
number
representation.
(P
olar
and
Smith
chart
formats
are
not
aected
by
the
scalar
formatting.)
Notice
in
Figure
6-2
that
after
formatting,
it
is
impossible
to
recover
the
complex
data.
Smoothing
This
noise
reduction
technique
smoothes
noise
on
the
trace
.
Smoothing
is
also used
to set
the
aperture
for
group
delay
measurements
.
When
smoothing
is
on,
each
point
in
a
sweep
is
replaced
by
the moving
average value
of
several
adjacent
(formatted)
points
.
The
number
of
points
included
depends on
the smoothing
aperture
,
which
can
be
selected
by
the
user
.
The
eect
is
similar
to
video
ltering. If
data
and
memory
are
displayed,
smoothing
is
performed
on
the
memory
trace
only
if
smoothing
was
on
when
data
was
stored
into
memory
.
F
ormat
Arrays
The
data
processing
results
are
now stored
in the
format
arrays
.
Notice
in
Figure
6-2
that
the
marker
values
and
marker
functions
are all
derived from
the
format
arrays
.
Limit
testing
is
also
performed
on
the
formatted
data.
The
format arrays
are
accessible
via
HP-IB
.
Oset and
Scale
These
operations prepare
the
formatted
data
for
display
.
This
is
where
the
reference
line
position,
reference line
value
,
and
scale
calculations
are
performed,
as
appropriate
to
the
format.
Display
Memory
The
display
memory
stores
the
display
image
for
presentation
on
the
analyzer
.
The
information
stored
includes
graticules
,
annotation,
and
softkey
labels
.
If
user
display
graphics
are
written,
these
are
also
stored
in
display
memory
.
When
a
print
or
plot
is
made
,
the
information
is taken
from
display
memory
.
The
display
is
updated
frequently
and
synchronously
with
the data
processing operations
.
Application and Operation Concepts 6-7