NI PXIe-5601 Calibration Procedure
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© National Instruments
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15
8.
Set the NI 5601 reference level according to Table 2 using the niRFSA Configure
Reference Level VI or the
niRFSA_ConfigureReferenceLevel
function.
9.
Set the NI 5601 center frequency according to Table 3 and the span according to Table 2
using the Center Span instance of the niRFSA Configure Spectrum Frequency VI or the
niRFSA_ConfigureSpectrumFrequencyCenterSpan
function.
10. Commit the settings to hardware using the niRFSA Initiate VI or the
niRFSA_Initiate
function.
11. If you use the spectrum analyzer, set the reference level, span, and resolution bandwidth
according to Table 4. Set the center frequency according to Table 5.
12. Set the RF source to the same frequency as the
NI 5601 Center Frequency
according to
Table 3.
13. At each NI 5601 center frequency and reference level setting, perform the following steps:
a.
Adjust the RF source power, in dBm, to satisfy the following equation:
Channel A Power
+
RF Input Calibration Factor
=
Reference Level
±1 dB
When making the adjustment, use the appropriate RF frequency for the channel A
sensor. Calculation of the
RF Input Calibration Factor
may require linear
interpolation.
Note
Set the signal generator to its maximum power if it does not have sufficient
power to reach the reference level.
b.
Record the
Channel A Power
.
c.
Measure the
Channel B Power
or
Spectrum Analyzer Power
using one of the following
methods:
•
If you are using the power meter, measure and record the
Channel B Power
. Use
the appropriate IF frequency from Table 5 for the channel B sensor.
•
If you are using the spectrum analyzer, measure and record the
Spectrum
Analyzer Power
. Correct the
Spectrum Analyzer Power
using the appropriate
IF Calibration Factor
for the IF frequency in Table 5 and the following equation:
Corrected Spectrum Analyzer Power
=
Spectrum Analyzer Power
+
IF Calibration Factor
d.
Calculate the
NI 5601 Calculated Gain
at each RF frequency using the following
formula:
NI 5601 Calculated Gain
=
Channel B Power
(or
Corrected Spectrum Analyzer Power
) -
(
Channel A Power
+
RF Input Calibration Factor
)
Use the same
RF Input Calibration Factor
that you used in step 13a.
14. Recall the
NI 5601 Stored Gain
for each test frequency using the niRFSA Downconverter
Gain property or the
NIRFSA_ATTR_DOWNCONVERTER_GAIN
attribute.
15. Calculate the
Absolute Gain Accuracy
using the following formula:
Absolute Gain Accuracy
=
NI 5601 Calculated Gain
-
NI 5601 Stored Gain
