RTG Calibration Error 5000 When Using the PXIe-5841

Issue Details

I am setting up the RTG system for the first time with the PXIe-5841 VST. When attempting to run the RTG system calibration, I consistently get error 5000: RTG calibration failed because the desired dynamic range could not be achieved. 

This error occurs every time I run the calibration and I am unable to complete the calibration process or achieve accurate results. 

Solution

This issue is most commonly caused by a missing external Local Oscillator (LO) connection between the TX and RX ports required when using the PXIe-5841 as shown in figure 18 in the RTG User Manual. Follow these steps to resolve the issue:

1. Verify the LO cable connection between the transmit and receive paths.

   • Connect the RF OUT LO OUT port to the RF IN LO IN port using an MMPX (m)-to-MMPX (m) cable.

2. Re-run the RTG calibration utility.

   • After connecting the LO cable, execute the calibration again to verify that the error is resolved.

It is recommended to perform a VST self-calibration through InstrumentStudio or the Hardware Configuration Utility (NI-HWCU) first before running the RTG system calibration for optimal performance. 

Additional Information

Unlike the PXIe-5831 and PXIe-5842 VSTs, the PXIe-5841 does not have internal shared LO paths between the RX and TX paths which is why the external LO loopback cable is required for this VST. The shared LOs between RX and TX ensures phase synchronous operations for the RTG. 

The NI part number for the recommended MMPX cable is 763577-0R152.