This example demonstrates how to perform Self Calibration with an external digitizer - Preselector Alignment for a NI PXIe-5665 14 GHz.
The external digitizer portions of the examples are shown using a NI PXIe-5622. If using a digitizer that is not NI branded,
before running the examples, the user needs to change the digitizer setup and power measurements portions to match the digitizer in use.
This example requires the use of a loop-back cable to ensure the downconverter is in sync with the clock of the NI PXIe-5653. Please connect
the loop-back cable from the Ref Out 10 MHz on the NI PXIe-5653 to the 10 MHz Ref In on the back of the chassis in use.
In this example, the VI iterates through 3 different frequencies and does a process at each of those frequencies. The process is to set the center
frequency for the downconverter, set the LO Frequency, then do a course sweep of the Preselector while taking power measurements. After taking the power
measurements, the center measurement is then found. The center measurement location is then used to again sweep the preselector, only this time doing
a finer sweep area with a smaller step size. After sweeping the preselector this time, we find the center meaurement location and use the -10 dB from center location.
Once the -10 dB center location for each of the 3 frequencies used is found, the VI calculates the best polynomial fit for those values. After doing a rough check of the
polynomial coefficients the coefficients are committed to onboard EEPROM on the downconverter if there are no errors and the commit boolean on the front panel is set to true.
