SpeedandAccuracy
The speed and accuracy of a power meter calibration vary depending on the test setup and the
measurement parameters. For example, number of points, number of readings, if the power is
less than -20
dBm,
continuous versus sample and sweep mode. Accuracy is improved if you
set the source power such that it is approximately correct at the measurement port. Power
meter calibration should then be turned on. With number of readings
=
2, very accurate
measurements are achieved.
‘lhble
6-7 shows typical sweep speed and power accuracy. The times given apply only to the
test setup for continuous correction or for the first sweep of sample-and-sweep correction.
The typical
values
given in
l’hble
6-7 were derived under the following conditions:
‘I&t
Equipment Used
a
HP 8753E network analyzer
n
HP 436A power meter
n
HP
8485A
power sensor
Stimulus Parameters
The time required to perform a power meter calibration depends on the source power and
number of points tested. The parameters used to derive the typical values in
‘lhble
6-7 are as
follows:
m
number of points: 51, 300
kHz
to 3
GHz
n
test port power: equal to calibration power
‘able
6-7.
Characteristic Power Meter Calibration Sweep Speed and Accuracy
Power Desired
Number
of
Beadings
Sweep Time Characteristic
at
lkst
Port
(dBm)
(secomls)l
Accuracy
(dB)2
1
33
1
I
f0.7
+6
2
04
f0.2
I I
3
I
96
1
fO.l
1
43
l
0.7
-16
2 92
f0.2
3 123
fO.l
1
194
f0.7
-30
2
360
f0.2
3 447
fO.l
1 Sweep speed applies to every sweep in continuous correction mode, and
to the
fkst
sweep in sample-and-sweep made.
subsequent
sweeps in
sample-and-sweep mode will be much faster.
2 The atxunwy values were derived by combining the
accuracy
of the
power meter and lineariw of the analyzer’s internal source, as well as
the
mismatch
uncertainty
associated with the power sensor.
6-106
Application and Operation Concepts
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