NI PXI 5610 procedure in Cal Executive

[Jerimiah]

I am currently working with the calibration executive software version 3.3 to calibrate some PXI-5610 cards. For the AmplitudeAccuracy_Super10MHz it has me manually input two measurements. In turn it appears to perform a calculation to determine the As found dB reading on the calibration report. However, I cannot seem to understand why two measurements are made and why the calculations appear inconsistent. For the same test at frequencies from 20MHz to 2.7GHz with a power level of -50dBm I input similar numbers for both values on all frequencies but received vastly different values.

Here is a specific example:

1005MHz @ -50dBm 256average 1st value: -50.54dBm 2nd value: -65.17 As found reading on report: -.5837

1500MHz @ -50dBm 256average 1st value: -50.67dBm 2nd value: -65.12 As found reading on report: -.8231

Does anyone know what the calculations are for this procedure and why/what I might be doing incorrectly to make my measurements inconsistent?

[Steve_B]

Hi Jerimiah,

I am taking a look into your question and I wanted to clarify a few things. What hardware are you using to make the measurements? Is it the recommended hardware or an unsupported model? Could you provide a screenshot of a couple rows of the AmplitudeAccuracy_Super10MHz section of the calibration report if you have it? It would also be helpful to have a screenshot of the prompts to enter the two measurements.  I am not sure of the calculation that is made based on your inputs, however I suspect the difference may be related to the passband flatness. Let me know what other information you can provide and I will continue looking into an answer.