National Instruments NI PXIe-5601, Calibration Procedure

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NI PXIe-5601 Calibration Procedure | © National Instruments | 43
Use the appropriate RF frequency for the channel A sensor. Calculation of the RF Input
Calibration Factor may require linear interpolation.
28. Measure and record the IF Power using the spectrum analyzer.
a. Set the spectrum analyzer center frequency to the RF start frequency in Table 29.
b. Measure the Spectrum Analyzer Power and calculate the IF Power value using the
following formula:
IF Power = Spectrum Analyzer Power + IF Calibration Factor
29. Calculate Gain using the following formula:
Gain = IF Power - RF Power
30. Store the appropriate calibration constants using the niRFSA Cal Adjust Reference Level
Calibration VI or the
niRFSA_CalAdjustRefLevelCalibration
function. Set the
following parameters:
•
ref level cal data type —If Mechanical Attenuator from Table 29 is enabled,
set to Default (or
NIRFSA_VAL_DEFAULT
). Otherwise,
set to Mechanical Attenuator Disabled
(or
NIRFSA_VAL_EXT_CAL_MECHANICAL_ATTENUATOR_DISABLED
).
• RF band —Set to 4 .
• attenuator table number —Refer to Table 29.
• frequency —Set to the corresponding frequency from step 14.
• gain —You computed this in step 29.
31. Increment the RF start frequency and the LO start frequency by the specified Step Size from
Table 29. Repeat steps 13 to 30 for each frequency up to and including the RF stop
frequency for each RF frequency starting with 10 MHz up to and including 120 MHz for
the first two rows of Table 29.
32. Repeat steps 13 to 31 for each RF Attenuation Index in the first two rows of Table 29.
33. Repeat steps 13 to 31 for the two remaining rows in Table 29, changing the niRFSA
Mechanical Attenuator Enabled property or
the
NIRFSA_ATTR_MECHANICAL_ATTENUATOR_ENABLED
attribute as indicated in
Table 29.
34. Use the temperature stored in Step 13 of the Reference Level Adjustment for
RF Frequencies ≥ 120 MHz section. Record the device temperature using the niRFSA Cal
Set Temperature VI or the
niRFSA_CalSetTemperature
function.
35. Close the NI 5601 Reference Level Calibration step using the niRFSA Close Calibration
Step VI or the
niRFSA_CloseCalibrationStep
function.
36. Close the external calibration by calling the niRFSA Close Ext Cal VI with the action
parameter set to Commit or by calling the
niRFSA_CloseExtCal
function with the
action parameter set to
NIRFSA_VAL_EXT_CAL_COMMIT
.
37. Close the niRFSG session using the niRFSG Close VI or the
niRFSG_close
function.