Jenne, Gabriele, Sheila, Hang

We modified the green WFS loops to make them higher bandwidth. See the first plot for the new OLTFs for XARM DOF1 (ctrling ETMX) P & Y.  Their gain were ~ x50 larger than the previous design, making the new loops have BWs of >~ 0.1 Hz. For DOF2 we also increased the loop gain by ~ x50. As the WFS loops being were much faster, the camera ones can also be faster as noticed by Stefan and TVo. The new gains are now put into the ALS guardian.

It turned out that previously we could not increase the BW of those loops because I foolishly forgot to low-pass the ctrl signal above the UGF. The high-freq noise then badly saturated the ETM PUM drivers. See the top panel of the second plot, the blue and cyan traces. We added a 4th order cheby1 lowpass at 1.5 Hz to each ctrl filter bank and now we can turn up the gains without major issues.

=======================================

Also notice that in the YARM green DC centering loops there exists a huge peak at ~ 350 Hz due to some instabilities in the PZT controller loops. Such signal can also be seen in the WFS signals as well (and dominated the previous ctrl signal rms before we put in the LP filters). It would be nice if someone could go to the Y end to fix it.