In case you don't see the attached plots please click here: 11698.

Instead of using a Butterworth filter I used an elliptic filter of the 4th order with band pass ripple of 1 dB and attenuation of 40 dB in th stop band. Still, in order to reach reduce the necessary amount of noise the square of the filter was necessary:

• The first plot shows the GAS filter control noise for all GAS stages without broadband damping filter, only the DC control filter is on.
• The second plot shows the control noise with the F0 damping filter on together with the  DC control filter on for all GAS stages.

The last plot indicates we will need to roll off the F0 damping filter.

I checked the stability for the BF using the filters and suspension models uploded in Foton. The unity gain frequency is 25 mHz with a phase at that frequency of -93 degrees.