I have created a new GDS calibration FIR filters file. The included filters are designed to correct output of the front-end CALCS calibration, improving accuracy at high frequencies on ~10% level. This new filters file contains more aggressive high-pass filters with a cutoff of 9 Hz and contains accurate values for EP1-9 for use in the kappa calculations. The new filters file can be found in the calibraiton SVN:
aligocalibration/trunk/Runs/PreER10/GDSFilters/H1GDS_1156183417.npz
This filter was created using calibration SVN version #3295 and following instructions outlined here.
Attached are plots of the corrections applied to DELTAL_RESIDUAL and each of the DELTAL_CTRL_PUM/UIM/TST/ channels (all DELTAL_CTRL_* channels receive the same corrections). Attached are also plots comparing the h(t) spectrum for some ER9 data (1152076416-1152076544) calibrated using this filters file with output of the front-end CALCS model. The agreement is at the expected level given the corrections include in the GDS filters.
The GDS calibration pipeline was restarted at 1157822672 with the above new filters file.
These filters include the use of a tukey window around the final time domain filter. This seemed to fix the spectral leakage issues seen by downstream tools. I believe the previous filters were not falling off smoothly enough and were adding low-frequency features to the h(t) data. This become noticable after switching to double precision channels, because the old dewhitening filters in use with the (whitened) single precision channels included the tukey window. Since these dewhitening filters were no longer in use when we switched to double precision channels without whitening, the issues with the residual and control correction filters became obvious.