As you can see, the shape of 60 - 110 Hz was similar in (blue) 10:30 and (red) 13:10, but floor level increasing.
If we can find this issue, we may obtain the hint for next step
Fig.2. showed the coherence between DARM and feedback signal to PR3 yaw.
In current ASC, PR3 yaw signal can be obtained from WFS REFL 45 I.
As shown in klog34400, there are several coherence in 115 Hz 140 Hz and 160 Hz in PDA45I (and 45Q).
If we perform the reshaping of ASC filter for the PRC2, there are possibility to reduce the peaks (or > 100Hz feedback would be too low to fluctuate the PR3 mirror?)
Yokozawa-san,
Since current PRC2 ASC signals are fedback to the setpoint of PR3 OpLevs, the effect of WFS signals through the feedback is smaller than that of OpLev signals.
So, if ASC signals contaminates DARM, it should be also seen in PR3 OpLev signals.
I don't think OpLev feedback affects at such high frequency but could you check the signals?
Apart from the control bandwidth. Does PR3 oplev QPDs have IR filters set?? If no, it might be contamination from the main IR scattered light.
(PR3 fluctuation was lower than the oplev noise or didn't move.)
