Self-Calibration

Self-calibration adjusts the PXIe-5831 for variations in the module environment using onboard power detectors.

PXIe-5831 modules are externally calibrated at the factory; however, you should perform a self-calibration in any of the following situations:

  • After first installing and interconnecting your PXIe-5831 instrument
  • After any module in the chassis is installed, uninstalled, or moved
  • After inter-module cabling has been changed, reconnected, or repositioned
  • After changing controllers, computers, or reinstalling the driver software
  • When the system is in an environment where the ambient temperature varies or the module temperature has drifted more than ±5 °C from the temperature at the last self-calibration
  • To periodically adjust for small performance drifts that occur with product aging
Note To ensure specifications before you use the instrument or perform self-calibration, power on the chassis and mmWave radio heads, if applicable; set the chassis fan speeds to AUTO or HIGH, depending on the chassis; wait for the operating system to completely load; and then allow the instrument to warm up for 30 minutes.
Note Ensure that any connected external hardware is in an idle state and not transmitting during self-calibration. It is not recommended to perform self-calibration while connected in direct loopback configurations.
Note For the best image rejection and LO leakage performance, it is recommended that you run Self Cal or Self Cal Range for only the image rejection and LO leakage portion if the temperature changes beyond ±1 °C.

Self-Calibration Adjustment Parameters

Self-calibration adjusts the following parameters of the PXIe-5831 to facilitate temperature correction:

  • LO1 and LO2 internal path gain
  • IF/TRX input gain
  • IF/TRX output gain
  • IF/TRX input frequency response
  • IF/TRX output frequency response
  • IF input residual LO power
  • IF output residual LO power
  • IF input residual sideband image
  • IF output residual sideband image
Note RF residual LO power and RF residual sideband images are only adjustable in self-calibration and cannot be corrected for during external adjustment. Self-calibration must be successfully executed after an external adjustment to ensure warranted performance.
Note NI recommends that no external signals are transmitted to the RF input port during the self-calibration.
Note NI-RFSA and NI-RFSG automatically perform self-calibration on the PXIe-5653 when the PXIe-5653 is associated with the PXIe-5831.