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Tue Apr 22 22:51:30 2008
I've been working a little on the MC WFS in the last few days. I have made many
changes to the sensing matrix script and also to the MCWFSanalyze.m script.
The output matrix, as it was, was not bad at low frequencies but was making noise in
the ~1 Hz band.
Turning the gain way down made it do good things at DC
and not make
things work higher.
The output matrix generating script now works after Rob fixed the XYCOM issue. Not sure
what was up there. As Caryn mentioned the SUS2.ini channels were all zero after Andrey's
PEM power cycle a few days ago. Rob booted c1susvme to get the SUS1 channels back and
today we did c1susvme2 to get the IOO-MC_L et. al. back.
Even after doing the matrix inversion there is some bad stuff in the output matrix. I
checked that the sensing matrix measurement has good coherence and I measured and set the
MC WFS RF phases (they were off by ~20-30 deg.). Still no luck.
My best guess now is that the RG filters I've used for POS damping and the movement of the
beam on the MC mirror faces has made a POS<->YAW instability at low frequencies. My next
move is to revert to velocity damping and see if things get better. Should also try redoing
the A2L on the MC1-3.