JeffreyK, SudarshanK, DarkhanT,
We compared DARM model for ER8, O1 with canonical DARM loop TF measurement and DARM loop measurement from Sep 23 (LHO alog 21868). The purpose of this analysis is to see if DARM OLG TF changed from Sep 10 (canonical parameter set for O1) till Sep 23, and to see how DARM time-varying parameters were estimated by kappa correction factors. The comparison show that the overall DARM OLG TF difference between two measurements is ~ 1% in magnitude and < 1 deg.
κtst and κC corrected O1 models* resulted in:
- sensing function magnitude residual to be mostly flat at ~ 2% offset (that looks like mostly systematic); systematic phase discrepancy did not change;
- reduction of actuation function meas/model magnitude residual from 4% (Sep 10) and 5% (Sep 23) to mostly under 2%; systematic phase discrepancy did not change;
- total DARM OLG TF meas / model magnitude residual reduced from 4-5% (in range [100 .. 200] Hz) to < 2%; systematic phase discrepancy did not change, notice that phase discrepancy of the O1 model at the reference time is ~ 10 deg at high frequencies (1 kHz).
*kappas were informed by cal. lines within 2 hours from both of the TF measurements (Sep 10 and Sep 23)
On calibration telecon we discussed that we could possibly accout for systemtic phase discrepancy in O1 model by applying time advance in actuation and sensing functions.
Earlier, after resolving some of the O1 DARM model issues we did a similar analysis that did not include Sep 23 measurement results, for details on analysis see LHO alog 21827.
The script that compares the models was committed to calibration SVN:
CalSVN/aligocalibration/trunk/Runs/O1/H1/Scripts/DARMOLGTFs/CompareDARMOLGTFs_O1.m (r1533)
