J. Kissel

It's been on the to-do list for several years now to move the EPICs gain of 1000 in to a filter module, such that H1's and L1's rough calibration into millamperes [mA] is done in a similar fashion (see comparison of how it's been done for years in G1700316, Appendix A, Slide 19). 

As such, I took the IFO down time this afternoon to
    (a) Clean up all the now obsolete O3-era whitening and transimpedance filter banks, and 
    (b) Move the EPICs gain of 1000 into a filter module, FM10, called "A2mA"

In doing so -- to sanity check that moving the gain into a filter bank produces the same output I compared an ndscope of the raw data, 
    H1:OMC-DCPD_A_OUT_DQ
    H1:OMC-DCPD_B_OUT_DQ
before and after the change. 

I was very surprised to see that there was a difference in gain on the DCPD B channel and even crazier, a cleaner character (less high frequency spikes) on both channels.

Unfortunately, as seems to be my life, a "quick sanity check" must now turn into a full fledged investigation as to what's going on.
Stay tuned on that.

In the mean time, I post screenshots (in order of appearance) of 
    - the "before" configuration of the banks, 
    - the design of the new "A2mA" filter, 
    - the diff of what changed in the filter backs according to the front-end, 
    - the "after" configuration of the banks,
    - the sanity check time series before vs. after (where the off-chart time in the middle is when both the A2mA gain of 1000 and the EPICs gain of 1000 are unphysically on for a moment while I switched)
    - the SDF acceptance of this new configuration.