Koji, Kiwamu, Stefan

We finished setting the BS drivealign matrix. Attached are the transfer functions of the two filters.
To test it we put in a 0.5Hz drive, and took a snapshot of a StripTool, starting without the drivealign elements, and ending with the L2P and L2Y drivealign elements engaged.

Note that we don't understand why the L2P coupling seems to fall faster than 1/f^4 above 3Hz. Since the measurement has very low coherence, this might actually be a measurement error. However, since the drive is so weak up there, this might actually not matter in practice.


The raw data is in
/ligo/home/controls/sballmer/20140115/BSTFdata
BSTF_v5measDone.xml
BSTFpitch_v5.xml
BSTFyaw_v5.xml

For reference, here are the actual filters used:

BS_M2_DRIVEALIGN_L2P:
zpk([0.0988999+i*0.419892;0.0988999-i*0.419892;0.0016662+i*0.747769;0.0016662-i*0.747769;
    0.77626+i*1.58279;0.77626-i*1.58279],[0.0545374+i*0.369777;0.0545374-i*0.369777;
    0.330458+i*2.11871;0.330458-i*2.11871;0.0573483+i*1.115;0.0573483-i*1.115;0.033991+i*0.481048;
    0.033991-i*0.481048],-0.010800065,"n")

BS_M2_DRIVEALIGN_L2Y:
zpk([0.0375136+i*1.25343;0.0375136-i*1.25343;0.185383+i*1.14346;0.185383-i*1.14346],
    [0.0211465+i*1.07707;0.0211465-i*1.07707;0.255547+i*1.35495;0.255547-i*1.35495],-0.00289650892,
    "n")