J. Kissel, J. Driggers

In prep for the move of calibration lines today -- to frequencies suggested by Jenne in LHO aLOG 48512 -- I've moved the elliptic band-stop for former 331.9 Hz line frequency to the new 410.3 Hz line frequency. Attached are bode plots comparing the two. Both former and new notches have gain around the DARM OLG UGF of around 1.00001 (they were both normalized at 0 Hz), and a we now have a whopping 0.04 more degrees of phase margin -- the message: this filter change has negligible impact on the DARM loop. The suppression at the calibration line frequency for the former and new notch are 0.0125 (-38.0 dB) and 0.0110 (-39.1 dB), respectively.

The new filter, 'EB410' has been loaded in to the DARM2 bank, overwriting the pre-existing filter, 'EB332' in FM8 This ensures all guardian automation involving this filter remains identical.
   The former design: ellip("BandStop",4,2,40,331.0,332.8)gain(1.25893)
   The new design: ellip("BandStop",4,2,40,409.4,411.2)gain(1.25893)

Other notes:
- We scanned all other global control loops for notches of the calibration lines, and found none in use.
- There is a notch for the 35 Hz calibration line, in LSC DARM1 FM8, called "EBS35" but is never in use (confirmed at least to be true during observation ready mode).