HP 8753D - Page 290

P
ower
Sweep
(dBm)
The
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POWER
SWEEP softkey
turns on
a power
sweep mode
that
is
used
to
characterize
power-sensitive
circuits
.
In
this
mode,
power is
swept at
a single
frequency,
from a
start
power
value
to
a
stop
power
value,
selected using
the 4
ST
ART
5
and
4
STOP
5
keys
and
the
entry
block.
This
feature
is
convenient
for
such measurements
as gain
compression or
AGC
(automatic gain
control)
slope
.
T
o
set
the
frequency
of
the
power sweep
, use
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CW
FREQ
in
the
stimulus
menu.
The
span of
the swept
power
is
limited
to
being
equal
to
or
within
one
of
the
eight
pre-dened
power
ranges
.
The
attenuator
will
not
switch
to
a
dierent
power
range
while
in
the
power
sweep
mode
.
Therefore
,
when
performing
a
power
sweep
,
power
range
selection
will
automatically
switch to
the
manual
mode
.
In
power sweep
,
the
entered
sweep
time
may
be
automatically
changed
if
it
is
less
than
the
minimum
required for
the
current
conguration
(number
of
points
,
IF
bandwidth,
averaging,
etc
.).
CW
Time
Sweep
(Seconds)
The
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CW
TIME
softkey
turns
on
a
sweep
mode
similar
to
an
oscilloscope
.
The
analyzer
is
set
to
a
single
frequency
,
and the
data is
displayed versus
time
.
The
frequency
of
the
CW
time
sweep
is
set
with
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CW
FREQ
in
the
stimulus
menu.
In
this
sweep
mode,
the data
is continuously
sampled
at
precise
,
uniform
time
intervals
determined
by
the
sweep
time and
the number
of
points
minus
1.
The
entered
sweep
time
may
be
automatically
changed
if it
is less
than
the
minimum
required
for
the current
instrument conguration.
In
time
domain
using
Option 010,
the
CW
time
mode
data
is
translated
to
frequency
domain,
and
the
x-axis
becomes
frequency
.In
this
mode
,
the
instrument
can
be
used
as
a
spectrum
analyzer
to
measure
signal
purity
,or
for
low
frequency
(
<
1
kHz)
analysis
of
amplitude
or
pulse
modulation
signals
.
Selecting
Sweep
Modes
In
addition to
the
previous
sweep
types
,
there
are
also
two
dierent
sweep
modes
.
These
can
be
accessed
through
the
correction
menu
by
pressing
4
CAL
5
]
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MORE
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ALTERNATE
A
and
B
or
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CHOP
A
and
B
.
Refer to
\Alternate and
Chop Sweep
Modes"
in
the
\Measurement
Calibration" section.
Modifying
List
Frequencies
List frequencies can be entered or modied using the edit list and edit subsweep menus
.
Application of the functions in these menus is described below
.
Edit list menu
The
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EDIT LIST
softkey within the sweep
type menu provides access to the edit list menu.
This menu is used to edit the list of frequency segments (subsweeps) dened with
the edit
subsweep menu, described next. Up to 30 frequency subsweeps can be specied, for a
maximum of 1632 points. The segments do not have to be entered in any particular order:
the analyzer automatically sorts them and shows them on the display in increasing order of
start frequency. This menu determines which entry on the list is to be modied, while the edit
subsweep menu is used to make changes in the frequency or number of points of the selected
entry.
Application and Operation Concepts 6-23