C. Cahillane, D, Tuyenbayev

In a previous alog alog 20946 I showed preliminary carpet plots of ER7 strain uncertainty based on changes in the calibration parameters |kappa_tst|, φ_kappa_tst, |kappa_pu|, φ_kappa_pu, kappa_C, f_c.
Here are some updated plots.  (Plots 1 - 6)

The data is now low-noise, and is dewhitened.  This gives much nicer, more accurate results.
I have been working to reproduce Darkhan's carpet plots from T1500422.  The method he uses to find error in Delta_L_ext is as follows:

delta Delta_L_ext =  C_true / (1 + G_true)     
                             ------------------------------
                                        C / (1+G)

where C_true and G_true are the quantities where kappa_tst, kappa_C, and f_c are varied.

The method I use to find error in strain is:

delta strain = (1 / C_true) * d_err + A_true * d_ctrl
                      ----------------------------------------------
                                  (1 / C) * d_err + A * d_ctrl

Plot 7 is Darkhan's method of computing error from changes in kappa_tst reproduced by me.
Plot 1 is my method of computing error from changes in |kappa_tst|.  They should be the same.  They aren't.

We are searching for potential reasons behind the structure found in Darkhan's plot.  Something odd may be going on at the UGF of the CLG, causing the low magnitude error near 65 Hz and low phase error near 35 Hz.
My plot, on the other hand, has no low error region in phase, in fact it has a maximum near 35 Hz, and has a tilted low magnitude error region between 30 and 40 Hz.

I am investigating this difference now.