Use a PXIe-5653 as an LO Source to PXIe-5831

The following article describes how to setup, configure, and execute software to enable the PXIe-5831 to be used with an external local oscillator (LO) to improve RF performance.  The 5831 can be configured in a variety of ways, however in the this article we will focus on Configuration 1:
Configuration 1:  PXIe-5820, PXIe-3622, and PXIe-5653
Configuration 2:  PXIe-5820 and PXIe-3622
Configuration 3:  PXIe-5820, PXIe-3622, PXIe-5653, and mmWave Heads (mmHD)

HW Reference:

• PXIe-5820 Vector Signal Transceiver
• PXIe-3622 Vector Signal Up/Down Converter
• PXIe-5653 RF Analog Signal Generator synthesizer/local oscillator (LO) source module

HW Requirements:

• System controller
• PXIe compatible chassis
• NI PXIe-5831
• NI PXIe-5653 (LO1 frequency range 3.2 GHz to 8.2 GHz)
• 3-6 dB attenuator
• Instrument capable of measuring power between 3.2 and 8.2 GHz, in this example we will be using the PXIe-5831.
• 152 mm MMPX (m)-to-SMA (m) cable 

SW Requirements:

• LabVIEW 2019 or later
• RFSA 19.6 or later
• RFSG 19.6 or later
• RFmx SpecAn 19.1 or later
• 5831 and 5653 LO.zip
  • RFSA Get LO Properties.vi
  • Configure 5653 LO1.vi
  • RFSG Single Tone Generation with PXIe-5653 Enabled.vi
  • RFSG Single Tone Generation.vi

Configuration Requirements:

• In NI MAX associate the PXIe-5820 with the PXIe-3622 to form a PXIe-5831.
  • PXIe-5831 Getting Started Guide  page 15 Configuring the PXIe-5831 in MAX.

1. Get the PXIe-3622 LO2 Frequency.

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• Open the RFSA Get LO Proporties.vi included in the .zip.
• Set up the front panel as shown.
  • Note your Resource Name might be different.
• Run the RFSA Get LO Properties.vi.
  • Note: The 3622 LO2 Frequency (Hz) indicator should return 4.25GHz.
  • Note: For other frequencies of interest simply change the carrier frequency.
• Record the PXIe-3622 LO2 Frequency as this will be used later.

• Run the Configure 5653 LO1.vi.  
• Measure and record the power as this will be used later.
• Stop the Configure 5653 LO1.vi.
• Disconnect the PXIe-5653 from the measuring instrument.

3.   Connect the output PXIe-5653 LO1 with the attenuator inline to the PXIe-3622 LO2 IN.

4.  Execute code to export the PXIe-5653 LO1 to the PXIe-3622 LO2 IN.

• Open RFSG Single Tone Generation with PXIe-5653 Enabled.vi that was included in the .zip.
• Set up the front panel as shown in the example.
  • Note: the PXIe-3622 LO2 Frequency (Hz) is the result from step 1.
  • Note: 2 the LO2 In Power is the result from step 2. 
• To perform a loopback test the following connections need to be made.

• Run RFSG Single Tone Generation with PXIe-5653 Enabled.vi.
• Open RFmx soft front panel and target the same 5831 using the RFSG Single Tone Generation.vi.
• Configure the RF Signal Analyzer as follows.

• Configure the Frequency Settings as follows.
• 

The resulting spectrum should resemble the following.

• Note: The output power of the acquired tone will vary based upon your attenuator and measurement instrument settings.

To highlight the difference in performance you can compare the phase noise measurement results of the PXIe-5831 verses the PXIe-5831 with the PXIe-5653.  Listed below are the results:

PXIe-5831

• Note: Measurement result was using the RFSG Single Tone Generation.vi included in the .zip
• Note:  Disconnect the PXIe-5653 from the PXIe-3622.

PXIe-5831 with PXIe-5653

• Note: Measurement result was using the RFSG Single Tone Generation with PXIe-5653 Enabled.vi included in the .zip
• Note: Refer to step 3 for connectivity between the PXIe-5831 and PXIe-5653

The measurement results above show ~10dBc of improved dynamic range.