Filiberto C., Daniel S., Marc P.
Today we successfully applied E1600252v2 to the OMC DCPD ISC Split Whitening Chassis S1101627. This change better accommodates the violin modes of the main LIGO optics in the vicinity of 500Hz that have a tendency to saturate the whitening chain's filters. The new filter replaces a 1Hz-10Hz zero-pole, with a 50Hz-500Hz pole-zero on the second filter channel. LLO had already completed these changes August 2016, ALOG.
Updated the DCPD whitening filter at stage 2 to a nominal zpk([50],[504],-1, "n"), ie., zero at 50 Hz, pole at 504 Hz, gain of -1. This may effect the calibration.