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ni.com
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PXIe-5673E Calibration Procedure
10. Set the niRFSG Power Level property to
0
dBm, and repeat steps 7 through 9.
11. Set the niRFSG Power Level property to
-30
dBm, and repeat steps 7 through 9, measuring
the power using both the power meter and spectrum analyzer. Use the following parameter
settings for the spectrum analyzer:
•
Center frequency: (Frequency in step 7) + 1 MHz
•
Reference level: -30 dBm
•
Frequency span: 0 Hz
•
Resolution bandwidth: 500 Hz
•
Sweep time: 20 ms
•
Reference clock source: External
•
Attenuation: 5 dB
•
Preamplifier: On
12. Use the power meter measurements to calculate a correction for the spectrum analyzer
inaccuracies and attenuator loss with the following equation:
Corrections [i] = Power Meter [i] - SpecAn [i]
Note
The
SpecAn [i]
values in the above equation are used only to determine the
Corrections [i]
values that are used in the
-60
dBm and
-90
dBm measurements
described in steps 13 and 14. When verifying the
-30
dBm measurements, you need
to use only the
Power Meter [i]
values.
13. Set the niRFSG Power Level property to
-60
dBm, and repeat steps 7 through 9 using only
the spectrum analyzer and its measured correction to measure the power accuracy using the
following spectrum analyzer parameter settings:
•
Center frequency: (Frequency in step 9) + 1 MHz
•
Reference level: -30 dBm
•
Frequency span: 0 Hz
•
Resolution bandwidth: 500 Hz
•
Sweep time: 20 ms
•
Reference clock source: External
•
Attenuation: 5 dB
•
Preamplifier: On
Note
To maintain the same measurement uncertainty as the power meter, you must
apply the corrections found in step 12 to the measured results, as shown in the
following equation:
AdjustedMeasurement [i] = SpecAn [i] + Corrections [i] + Splitter Loss [i]
