HP 8753D - Page 366

T
able 6-6.
Characteristic
Power
Meter
Calibration
Sweep
Speed
and
A
ccuracy
P
ower
Desired
at
T
est
P
ort
(dBm)
Number
of
Readings
Sweep
Time
(seconds)
1
Characteristic
A
ccuracy
(dB)
2
1 33 6
0.7
+5 2 64 6 0.2
3 95 6
0.1
1 48 6
0.7
0
15
2 92 6
0.2
3 123 6 0.1
1 194 6
0.7
0
30
2 360 6
0.2
3 447 6
0.1
1
Sweep speed
applies
to
every
sweep
in
continuous
correction
mode
,
and
to
the
rst
sweep
in
sample-and-sweep
mode
.
Subsequent
sweeps
in
sample-and-sweep
mode
will
be
much
faster
.
2
The
accuracy values
were derived
by combining
the accuracy
of
the
power
meter
and
linearity
of
the
analyzer's
internal
source
,
as
well
as
the
mismatch
uncertainty
associated
with
the
power
sensor
.
Notes
On
A
ccuracy
The
accuracy
values
in
T
able
6-6
were
derived
by
combining
the
accuracy
of
the
power
meter
and
linearity
of
the
analyzer's
internal
source
,
as
well
as
the
mismatch
uncertainty
associated
with
the
test
set
and
the
power
sensor
.
P
ower
meter
calibration
measures
the
source
power
output
(at
the
measurement
port)
at
a
single
stimulus
point,
and
compares
it
to
the
calibrated
power
you
selected.
If
the
two values
are
dierent,
power
meter
calibration
changes
the
source
output
power
by
the
dierence
.
This
process
is
repeated
at
every
stimulus
point.
The
accuracy
of
the
result
depends
on
the amount
of
correction
required.
If
the selected
number of
readings =
1, the
nal
measurement
accuracy
is
signicantly
aected
by
a
large
power change
. However
,if
the
selected
number
of
readings
is
>
1,
the
power
change
on the
second or
third reading
is
much
smaller:
thus
accuracy
is
much
better
.
Set source
power approximately
correct at
the
measurement
port,
then
activate
power
meter
calibration. This
method can
signicantly increase
the accuracy
of the
measurement
when
the
selected number of readings = 1. Smaller accuracy improvements occur with
a higher number
of readings
. Remember that mismatch errors aect accuracy as well.
Note
Power meter correction applies to one port only; the other port is not
corrected.
Application and Operation Concepts 6-99