NI PXI-5650/5651/5652 Calibration Procedure
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© National Instruments
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15
Note
The main frequency synthesis occurs between 1.6 GHz and 3.3 GHz using
one of four voltage-controlled oscillators (VCO). Frequencies outside this range are
generated by using dividers or multipliers. For frequencies lower than 1 GHz, the
SSB phase noise can be characterized by the following relationship (use the 1 GHz
measurement as your reference):
SSB Phase Noise
TEST
=
SSB Phase Noise
REFERENCE
- 20log(
n
)
where
SSB Phase Noise
TEST
= SSB phase noise at the center frequency of interest
in dBc/Hz
SSB Phase Noise
REFERENCE
= SSB phase noise at the referenced center frequency
of interest in dBc/Hz
n
=
Reference/Test
in Hz/Hz
Verifying Nonharmonics at 0 dBm to -20 dBm Output Power
Complete the following steps to verify the nonharmonic levels of an 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.
Generate a signal after setting the following NI-RFSG property settings:
•
Frequency (Hz): 35.125 MHz
•
Power Level (dBm): 0 dBm
•
Generation Mode: CW
•
Reference Clock source: RefIn
6.
Configure the spectrum analyzer with the following settings:
•
Frequency: 35.125 MHz
•
Reference level: +5 dBm
•
Resolution bandwidth: 1 kHz
•
Span: 500 kHz
•
Reference Clock source: External
7.
Measure the peak power of the fundamental tone using the spectrum analyzer and record
the value. This value is your reference value for steps 8 through 16.
8.
Reconfigure the spectrum analyzer with the following settings:
•
Center frequency: 35.125 MHz + 51.5 kHz offset
•
Reference level: +5 dBm
•
Span: 97 kHz
