BrianL, JimW

Brian and I are investigating the HAM3 .6hz, looking at the tfs we took post chamber closeout in 2014. Brian wanted to look for the possibility of some magnetic coupling from the actuators to the sensors, so we were looking more closely at the cross terms in the transfer functions. We looked at a lot of the cross couplings, but most of them were uninteresting. We thought we found something on the V3 actuator on HAM3 (first pdf) at about .65 hz, but when we looked at HAM2 (second pdf), the feature is even bigger, so we suspect that this is maybe due to the payload. It is suspicious that the vertical drive to horizontal coupling changes slope at about .6 hz, but not very conclusive. 

I've also attached the script that we used to make the plots, but to run it you will have to correct the path to the data. The measurements we looked at were H1_ISI_HAM2_TF_L2L_Raw_2014_09_16.mat and H1_ISI_HAM3_TF_L2L_Raw_2014_09_10.mat in the HAM2 and HAM3  /Data/Transfer_Functions/Simulations/Undamped folders in the Sei SVN.