I disabled the OL loops for ITMX, ITMY and BS at GPStime 1194897655 to come up with an Oplev noise budget. OL spots were reasonably well centered - by that, I mean that the PIT/YAW error signals were less than 20urad in absolute value.
Attachment #1 is a first look at the DTT spectra - I wonder why the BS Oplev signals don't agree with the ITMs at ~1Hz? Perhaps the calibration factor is off? The sensing noise not really flat above 100Hz - I wonder what all those peaky features are. Recall that the ITM OLs have analog whitening filters before the ADC, but the BS doesn't...
In Attachment #2, I show comparison of the error signal spectra for ITMY and SRM - they're on the same stack, but the SRM channels don't have analog de-whitening before the ADC.
For some reason, DTT won't let me save plots with latex in the axes labels... |