Evan G., Jeff K.

This is a similar fix that had already been carried out on ETMY ESD output filter bank (see LHO aLOG 40508).

We moved a compensation zero out of the ETMX ESD output filter bank for each quadrant that had generated an uncompensated 5.2 kHz pole in the DARM loop (see LHO aLOG 33927). This resulted in an effective delay of ~20 usec. There is adequate roll off already from a low pass filter in the ESD driver, so moving this out of the DARM loop will be minimally impactful. Instead, the compensation zero will be a compensation pole in the CAL-CS path and doesn't result in an additional 5.2 kHz zero being added to the Foton filter.

We leave the filter in place and turned on, but the design string is now simply zpk([], [], 1, "n")

The new filter is installed in CS_DARM_ANALOG_ETMX_L3, FM5: zpk([], [3323.4210], 1, "n") (this comes from the mean of the summing node poles, see LHO aLOG 27619)

Removing this from the DARM path means that we need to include these as an uncompensated poles in the DARM model.

We have confirmed that this has now been moved out of the SUS ESD output filter banks and into the CAL-CS filter banks for both arms, thus resolving FRS ticket 7351.