jeffrey.kissel@LIGO.ORG - posted 12:52, Saturday 30 May 2015 - last comment - 15:59, Saturday 30 May 2015(18719)
H1OMC Filter Coefficients Loaded
J. Kissel, E. Merilh, D. Barker
There was an errant message for a pending filter change to be loaded in the H1OMC front-end model this morning that Ed and Dave wished to be cleared. Initially I thought this was because of Evan's changes last night who was widening a few notches for the stability high-frequency control of DARM, so reloaded the filter coefficients. However I've diffed the last three filter coefficient loads, and it appears as though there was now difference between the foton files in my load and the previous load:
jeffrey.kissel@opsws5:/opt/rtcds/lho/h1/chans/filter_archive/h1omc$ diff H1OMC_1117049961.txt H1OMC_1116981302.txt
jeffrey.kissel@opsws5:/opt/rtcds/lho/h1/chans/filter_archive/h1omc$ tconvert 1117049961
May 30 2015 19:39:05 UTC
jeffrey.kissel@opsws5:/opt/rtcds/lho/h1/chans/filter_archive/h1omc$ tconvert 1116981302
May 30 2015 00:34:46 UTC
whereas Evan's filter changes appear in the previous load:
jeffrey.kissel@opsws5:/opt/rtcds/lho/h1/chans/filter_archive/h1omc$ diff H1OMC_1116981165.txt H1OMC_1116981302.txt
132c132
< # DESIGN LSC_DARM 5 ellip("BandStop",4,1,80,1370,1570)ellip("BandStop",4,1,80,1900,2000)gain(1.25893)
---
> # DESIGN LSC_DARM 5 ellip("BandStop",4,1,80,1370,1570)ellip("BandStop",4,1,80,1900,2000)
137c137
< # DESIGN LSC_DARM 8 ellip("BandStop",4,1,100,480,527)ellip("BandStop",4,1,80,965,1040)gain(1.25893)
---
> # DESIGN LSC_DARM 8 ellip("BandStop",4,1,100,480,527)ellip("BandStop",4,1,80,965,1040)
156c156
< LSC_DARM 5 12 8 16384 0 vStop2,3 0.8566107853664323 -1.6767014787035512 0.9206465781685556 -1.7005774752522538 1.0000000000000000
---
> LSC_DARM 5 12 8 16384 0 vStop2,3 0.68042765313912 -1.6767014787035512 0.9206465781685556 -1.7005774752522538 1.0000000000000000
167c167
< LSC_DARM 8 12 8 16384 0 vStop0,1 0.9393306641627603 -1.9479818388350045 0.9800449573887594 -1.9633364657747414 0.9999999999999999
---
> LSC_DARM 8 12 8 16384 0 vStop0,1 0.7461341489699668 -1.9479818388350045 0.9800449573887594 -1.9633364657747414 0.9999999999999999
jeffrey.kissel@opsws5:/opt/rtcds/lho/h1/chans/filter_archive/h1omc$ tconvert 1116981165
May 30 2015 00:32:29 UTC
I don't know why the most recent two files see nothing when diffed.
As for the previous load: the violin notches in LSC-DARM have no gain normalization factors. There's nothing illegal about this, but it is bad filter hygiene. Together these two filters give almost 4 dB of attentuation to the entire loop.
I fixed this, loaded the coefficients, but then decided that maybe it was not a good idea to change the DARM gain while Kiwamu and Jeff were trying to calibrate the loop. So I unfixed it and loaded the coefficients again. That's why you see these coefficients disappear in the diff posted above.