Performing Generation RF System Compensation

Use the InstrumentStudio RPS plugin to perform generation RF system compensation on your system.

Note Generation RF system compensation is a required step to use multichannel relative phase and amplitude corrections on your system. Skip this step for 1-channel generation configurations.
Gather the following cables.
Table 11. Additional Cables
Channel Count Cable/Accessory Recommended Part Number Quantity
2 SMA-to-SMA cable (0.3 m or 0.6 m lengths)* NI 137833-0300/0600 2
4 SMA-to-SMA cable (0.3 m or 0.6 m lengths)* NI 137833-0300/0600 4
* The cables ideally should be the same length.
  1. Ensure that you cabled the LOs and reference clocks as outlined in Interconnecting the VSTs.
  2. Ensure that you performed self-calibration as outlined in Performing VST Self-Calibration.
  3. Ensure that you performed acquisition RF system compensation for the desired settings as outlined in Performing Acquisition RF System Compensation. Any compensation vectors used for generation RF system compensation must have a matching acquisition RF system compensation at the same compensation vectors.
  4. Connect RF IN to RF OUT to put each instrument in loopback.
    Figure 13. Connecting the RF IN and the RF OUT Terminals

    PXIe-5842 instruments cabled for generation RF system compensation.

  5. Launch InstrumentStudio by navigating to Start » National Instruments » InstrumentStudio.
  6. Click Manual layout.
  7. In the Edit Layout window that opens, under Add-Ons » RPS Plugins » System Compensation: RF System Compensation, select Create a large panel. Click OK.
    The RF System Compensation panel opens.
    Figure 14. RF System Compensation Panel

    RF System Compensation panel showing configuration and graph settings.

  8. Ensure the IP address and port number are correct and click Connect to establish a connection to the RPS.exe application.
    • Use localhost if the InstrumentStudio panel and ICsc window are running on the same computer.
    • Enter the IP address and listening port number from the ICsc window if the InstrumentStudio panel and ICsc window are running on different computers on the same network.
  9. Set the Configuration parameters.
    • Instr Type—Select Generation to perform a generation RF system compensation.
    • Comp Type—Select Coherent or Aligned.
    • Sync Reference—Select None or Acquisition for a generation instrument type.
    • Comp Reference—Select None, Coherent, or Aligned for a generation instrument type.
    • Instruments—Select the VSTs in the system. Ensure they are listed in order of the reference clock daisy-chain cabling.
  10. Set the Generation Settings parameters.
    • Ref Clk Topo—Select Daisy Chain because the generation instruments are part of a multi-VST configuration.
    • LO Source—Select Onboard or SG SA Shared.
    • Multi Chassis—Enable or disable. Both settings are valid because the signal source is a single instrument.
  11. Set the Acquisition Settings parameters.
    • Ref Clk Topo—Select Daisy Chain because the acquisition instruments are part of a multi-VST configuration.
    • LO Source—Select Onboard or SG SA Shared.
    • Multi Chassis—Disable to use the default signal routing within a single PXIe chassis. Enable if the acquisition instruments are used across multiple chassis.
  12. Set the Bandwidth Sweep parameters. Configure the Start, End, and Delta values (in Hz) to create a sweep of instantaneous bandwidths. If the Start and End values are the same, only the Start value is used.
  13. Set the Frequency Sweep parameters. Configure the Start, End, and Delta values (in Hz) to create a sweep of center frequencies. If the Start and End values are the same, only the Start value is used.
  14. Set the Reference Level Sweep parameters. Configure the Start, End, and Delta values (in dBm) to create a sweep of reference levels. If the Start and End values are the same, only the Start value is used.
  15. Click START.
    The RFSysComp process saves adjustments to %PUBLIC%\Documents\National Instruments\RF System Compensation. No manual interaction is required. Files are found automatically when applying them later.
  16. Interpret the graphs in RFSysComp UI:
    • Relative Phase Difference (Degrees)—This graph shows the channel-to-channel phase difference at discrete points in the instantaneous bandwidth—a snapshot of the performance of the latest completed calibration vector.
    • Relative Amplitude Difference (dB)—This graph shows the channel-to-channel amplitude difference at discrete points in the instantaneous bandwidth—a snapshot of the performance of the latest completed calibration vector.
  17. Disconnect the SMA-to-SMA cables from the RF OUT and RF IN terminals of the VSTs.