marc.pirello@LIGO.ORG - posted 12:55, Tuesday 19 July 2022 - last comment - 13:25, Tuesday 19 July 2022(64023)
HAM-A Coil Driver De-Whitening Filter Modificaitons OM1, OM2, OM3
We removed three coil drivers which drive OM1, OM2, and OM3 from SUS - C8 rack in the CER and replaced these with new coil drivers modified to the T2100410 standard. This modifiication is meant to reduce jitter coupling to the AS Port GW readout channels.
In testing for these the noise measurements were not so straight forward, and required a special cable to complete the measurements. This cable is differential with 100 ohms in line resistance on both inputs. The test procedure will be updated to reflect this.
S1200614 was replaced with S2001164
S1200612 was replaced with S1201160
S1106043 was replaced with S2001167
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New OM coil compensation filters:
| New | Old | |
|---|---|---|
| LPM1 | zpk([52.32;50.77],[0.5;3174],1,"n") | zpk([9.99999;20.9999],[0.9;211.883],1,"n") |
| AntiLPM1 | zpk([0.5;3174],[52.32;50.77],1,"n") | zpk([0.9;211.883],[9.99999;20.9999],1,"n") |