Reports until 10:11, Friday 27 March 2015
H1 SEI
jim.warner@LIGO.ORG - posted 10:11, Friday 27 March 2015 - last comment - 10:27, Friday 27 March 2015(17521)
HAM Blends: Same trick, different dog

Similar to my mods at ETMX in alog 17488, I thought I would try add some low pass filters to one of the HAM's CPS blend filters. So far I've gotten mixed results. HAM6 shows a pretty clear improvement, HAM5 is about 50/50 good and bad. First plot shows HAM6, second is HAM5, solid is before, dashed is after, black is ground, blue is CPS, red is GS13. HAM6 shows improvement between  1 hz and 10, but HAM5 is better up to 3 or 4 hz, then worse. At least the HAM 5 data shows nothing worse below a HZ, the HAM6 data was taken really quick so I didn't get the low frequency part.

Not really sure what is going on. Maybe insufficient loop gain or something?

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jim.warner@LIGO.ORG - 10:27, Friday 27 March 2015 (17522)

Adding plots of the blend filter change. Red is stock, blue is the added filter, green is the product.

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