[Aaron Viets, Alex Urban]

I modified the filter generation code to store a transfer function for the pcal correction factor. The name of the numpy array is "y_arm_pcal_corr."  It is an array with 3 rows, the first of which is frequency (0 to 8192 Hz in increments of 0.25 Hz), and the next two of which are the real and imaginary parts of the transfer function at that frequency. So, for example, to get the pcal correction factor at 100 Hz, you would do:

filters['y_arm_pcal_corr'][1][400] + 1j * filters['y_arm_pcal_corr'][2][400]

Unfortunately, we don't know a way to store complex values in the filters files, so this is haw we have to store them (for now, at least).

I made two filters files for LHO, one for GDS and one for DCS. They are in the calibration SVN under aligocalibration/trunk/Runs/O2/GDSFilters/ and the names are:

• H1GDS_highpass_1175954418.npz
• H1DCS_highpass_1173225472.npz

They are valid for the last portion of O2, the same time periods for which the latest filters were used as listed on the O2 calibration configurations wiki.

I did a quick spot check to see that the transfer functions were computed correctly, by just comparing their values at the calibration lines to the values included in the filters for those lines, which we know to be correct.