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National Instruments Corporation
21
NI PXIe-5611 Calibration Procedure
Adjustment
Following the adjustment procedure automatically updates the calibration
date and temperature in the EEPROM of the NI 5611. The calibration date
is also updated when you call the niRFSG Initialize External Calibration
and niRFSG Close External Calibration VIs.
Adjustment involves the following NI 5611 procedures:
•
LO filter response
•
LO path gain
•
Modulation impairments
•
RF path gain
Adjusting LO Filter Response
This adjustment yields a reduced LO second harmonic. Complete the
following steps to adjust the LO filter response of the NI 5611 using a
spectrum analyzer.
1.
Connect the NI 5611 LO OUT front panel connector to the spectrum
analyzer RF INPUT front panel connector.
2.
Connect the PXI Express chassis 10 MHz REF IN rear panel connector
to the spectrum analyzer 10 MHz REF OUT rear panel connector on
the spectrum analyzer.
3.
Call the niRFSG Initialize External Calibration VI.
4.
Call the niRFSG Initialize LO Filter Calibration VI.
Note
The
Filter to Calibrate
parameter on the niRFSG Initialize LO Filter Calibration
VI is by default set to
All Filters
. If you set the
Filter to Calibrate
parameter to another
filter setting, you must repeat steps 4 through 8 for each filter.
5.
Call the niRFSG 5611 Configure LO Filter Calibration VI.
6.
Use the spectrum analyzer to measure the mean output power using the
following spectrum analyzer parameter settings:
•
Center frequency: frequency specified by the
Frequency to
Measure (Hz)
parameter of the niRFSG 5611 Configure LO
Filter Calibration VI
•
Reference level: +5 dBm
•
Frequency span: 0 Hz
•
Resolution bandwidth: 500 Hz
•
Sweep time: 5 ms
