Jenne, Sheila, Peter, Evan, Stefan

We had been using AS45I for SRM signal in the last two days, and they seemed to not work well for yaw today.  Peter and Jenne noticed that the violin modes showed up more strongly in some quadratns of the AS45 WFS than others, so we drove a line in DARM to check the balancing of the AS45 WFS. We drove DARM at 21 Hz, and  looked at the transfer functions to the individual quadrants before the phasing.  We set the gains so that the signal amplitudes would all match quadrant 1.  For AS A, we ended up with gains as different from 0 as 0.69

We then attempted to phase these signals in the same way that the LSC AS45 detector is phased, by turning on and off the DARM offset and making sure that all the DARM signal was in the Q phase.  To do this we changed some phases by up to 20 degrees.  We had to use a step size of 0.5degrees on AS A which is in loop for DHARD to avoid loosing lock.  

After doing this we tried moving the SRM alingment to see if the AS45 signals were better for SRM.  We saw that pit and yaw were cross coupled, and we didn't have much pitch signal at all.  We reverted these changes since we don't really think that the gains in the electronics can be this badly matched.