Kiwamu, Darkhan
Recently we analyzed our measurements of AI chassis taken at LHO EY before ER7 (see LHO alog 18639) and fit a zpk filter to a mean of measurements of 20 AI channels using LISO. Standard deviation in magnitude between these measurements were +/- 0.0001 V/V (see LHO alog 18628).
In DARM OLGTF model for ER7, AA/AI chassis TF model was based on measurements taken at LLO (see notes in Matlab file by Joe B and Jeff K that was used to create AA model). LHO EY measurements have a noticably smaller residual over newly created zpk model of AA/AI chassis transfer function at higher frequencies > 1 kHz, than the AA/AI model for ER7. Currently we are using this new AA/AI model to create DARM OLGTF Matlab model for ER8/O1.
Notice that in AA/AI chassis model for ER7 gain at DC was manually normalized to 1.0 [V/V] (it can be seen in the Matlab script that was used to create AA/AI model for ER7). In the AA/AI model for ER8/O1 we did not manually normalize gain at DC to be 1.0, because LHO EY measurements from pre ER7 showed gain of 0.9902 +/- 0.0001 [V/V] at DC (see LHO alog 18628).
LISO output, Matlab script and resulting model were uploaded into calibration SVN:
CalSVN/aligocalibration/trunk/Runs/ER8/H1/Scripts/AAAI/fit_eyaifilter.fil
CalSVN/aligocalibration/trunk/Runs/ER8/H1/Scripts/AAAI/gen_H1ER7_AA_upto10kHzFitLTI.m
CalSVN/aligocalibration/trunk/Runs/ER8/H1/Scripts/AAAI/20150813_H1ER7_AA_upto10kHzFitLTI.mat
Parameters of the filter is given below (.FIL file, output of LISO is in SVN in the same directory):
# This is a LISO fitting script which fits the measured
# H1ETMY AI analog responses.
#
# Aug-13-2015
#
# KI
# $Id$
# $HeadURL$
pole 10.6615185502k 1.0770982348 ### fitted (name = pole0)
pole 7.7365806353k ### fitted (name = pole1)
pole 50.0077782214k ### fitted (name = pole2)
zero 65.8451204260k 5.7956773354k ### fitted (name = zero0)
factor 990.2583471071m ### fitted
delay 358.2748303132n ### fitted
param pole0:f 9k 12k
param pole0:q 0.5 2
param pole1:f 5.0k 10k
param pole2:f 20k 70k
param zero0:f 60k 70k
param zero0:q 1 300k
param factor 0.9 1.2
param delay 0 30u