Continuing a trend of stealing from LLO without shame, I looked at the L1 ISI foton file (via LLO's DAQ svn) to see what filters they were using for St1 sensor correction. I've attached some plots comparing some of the filters. It would be helpful if someone at LLO could summarize (again) what is being used in a complete and accurate way, because some of the filters have very similar names. FF is a common name for different filters. In the first plot, the green (I think) line is the sensor correction a version of the filter Rich Mittleman designed, that we have been using at ETMX with the BRS. The other lines, with an rdr are Ryans filters that I found in the LLO ITMY foton file, which I named based on what direction I found them. Second plot is the phases of same filters, with the same color scheme and order.
zpk's for the different filters:
rdr X,Y & Z Senscor
zpk([0.005868986282643151+i*0.005869222531082809;0.005868986282643151-i*0.005869222531082809;0;0;0;
0],[0.02121320343296193+i*0.0212131204375177;0.02121320343296193-i*0.0212131204375177;0;0;
5.326821252114442e-10;0.03999999945769176;0.0999999989897627;1.299999570000159;
6.999932741807108],6217465930.447066,"n")
rdr Y Senscor
zpk([0.006840399999901201+i*0.01879390059988029;0.006840399999901201-i*0.01879390059988029;
0.06062180000003715+i*0.03500000003808696;0.06062180000003715-i*0.03500000003808696;0],
[0.01368079999995818+i*0.03758769978878637;0.01368079999995818-i*0.03758769978878637;
0.03500000000007082+i*0.0606217999686012;0.03500000000007082-i*0.0606217999686012;
0.01000000066387688;0.03999999933609382],99.46935875676593,"n")
Mittleman Senscor
zpk([0.05785089999994956+i*0.06894400006181636;0.05785089999994956-i*0.06894400006181636;0;0;
1.054942208843087e-09;0.009999998945009785],
[0.003420200000103372+i*0.00939692986876447;0.003420200000103372-i*0.00939692986876447;
0.01267849999986304+i*0.02718920009938821;0.01267849999986304-i*0.02718920009938821;
0.04499510000006567+i*0.05362309993610679;0.04499510000006567-i*0.05362309993610679;
0.005000000000048375],0.006161864174656091,"n")
rdr Z Senscor
zpk([0;0;0],[0.003535529999897033+i*0.003535531890194072;0.003535529999897033-i*0.003535531890194072;
0.000868241000053361+i*0.004924041464289278;0.000868241000053361-i*0.004924041464289278;
50.0000000000001],252959718.8553666,"n")
The "Mittleman" and rdr Z" Filters (pink and green?) are both for use only with Z or a tilt correct tranlsation signal using Krishna's tilt meter.
The red, "rdr X,Y & Z" is Ryans 0.5Hz notch filter deisgned to be used in parallel with low frequency stage 1 feedback.
The blue is a substitute for the FIR filter chain(the FIR filter probably is better), obvously has a different sign from the others.