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National Instruments Corporation
13
NI PXIe-5611 Calibration Procedure
4.
Compare the measured LO OUT output power to the limit in Table 4.
5.
Repeat steps 2 through 4 for every frequency from 85 MHz to 6.6 GHz
in 10 MHz increments, including endpoints.
If the results are within the selected test limit, the device has passed this
portion of the verification.
Verifying Modulation Impairments
Complete the following steps to verify the modulation impairments of the
NI 5611 using a spectrum analyzer.
1.
Connect the NI 5611 RF 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.
Generate a single-sideband tone with a +1 MHz offset from the carrier
signal with the following NI-RFSG property settings:
•
Frequency (Hz): 85 MHz
•
Power Level (dBm): 0 dBm
•
Generation Mode: Arb Waveform
•
Reference Clock Source: ClkIn
The image appears at 84 MHz, and the carrier leakage at 85 MHz.
4.
Use the spectrum analyzer to measure the mean power of the RF output
using the following spectrum analyzer parameter settings:
•
Center frequency: Frequency in step 3 + 1 MHz
•
Reference level: +5 dBm
•
Frequency span: 0 Hz
•
Resolution bandwidth: 500 Hz
•
Sweep time: 5 ms
•
Reference clock source: External
Note
Zero-span mode shortens test time by avoiding unnecessary frequency sweeping.
To obtain the average power, convert the zero-span trace data to linear volts, perform a
mean calculation, and then convert the linear volts back to dBm.
Table 4.
LO Path Gain Verification Upper Test Limits
LO OUT Power (dBm)
As Found LO OUT Power
Accuracy Test Limits (dB)
As Left LO OUT Power
Accuracy Test Limits (dB)
0
±2.0
±1.0