I took beatnote measurements and spanned gain values in the PMC to see if stability issues in PMC loops can be affecting the FSS downstream.

Method

• I used BNspec.py with default settings (10 kHz bandwidth at 15.625 kSa/s for 60s) while spanning the parameter space of PMC gains.
• The beatnote frequency was robustly within 2 kHz of 27.34 MHz during this whole measurement.
• The overall experiment was run by spanParamSpace.py script.
• First I spanned North gains using the last optimum values found for South Side and tried to span the area towards which we found minima earlier.
• Next, I used the new minima found for North side and spanned region in South side.
• This time, I used sum of the ASD of beatnote frequency between 300 to 600 Hz to determine improvement in noise overall.
• Still, I would say, the improvement is hardly more than 5% over large areas of parameter space, meaning mostly BN noise is independent of these gains.

Final result

Data