NI PXI-5650/5651/5652 Calibration Procedure
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© National Instruments
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21
Verifying Harmonics at -50 dBm (Functional Test)
Complete the following steps to verify the harmonic levels of the PXI-5650/5651/5652 module
using a spectrum analyzer:
1.
Connect the PXI-5650/5651/5652 REF IN/OUT front panel connector to the rubidium
10 MHz frequency reference signal.
2.
Connect the 6 dB precision attenuator to the PXI-5650/5651/5652 RF OUT front panel
connector.
3.
Connect the spectrum analyzer RF INPUT connector to the 6 dB precision attenuator.
4.
Connect the rubidium 10 MHz frequency reference signal to the spectrum analyzer
10 MHz REF IN rear panel connector.
5.
Configure the spectrum analyzer with the following settings:
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Center frequency: 10 MHz
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Reference level: -45 dBm
•
Resolution bandwidth: 50 Hz
•
Frequency span: 500 Hz
•
Reference Clock source: External
6.
Generate a signal after setting the following NI-RFSG property settings:
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Power Level (dBm): -50 dBm
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Frequency (Hz): 10 MHz
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Generation Mode: CW
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Reference Clock source: RefIn
7.
Measure the peak signal value of the fundamental frequency using the current settings on
the spectrum analyzer. Record this value.
8.
Reconfigure the spectrum analyzer with the following settings:
•
Center frequency: Twice the center frequency from step 5
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Reference level: -45 dBm
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Resolution bandwidth: 50 Hz
•
Frequency span: 500 Hz
•
Reference Clock source: External
9.
Measure the peak signal value of the second harmonic using the settings of the spectrum
analyzer configured in step 8. Record this value.
10. Subtract the measurement in step 7 from the measurement in step 9.
