evan.hall@LIGO.ORG - posted 20:10, Sunday 31 January 2016 - last comment - 09:50, Monday 01 February 2016(25275)
45 MHz phase noise coupling into DARM
I remeasured the 45 MHz phase noise coupling into DARM, this time with broadband excitation. No surprises here; it looks the same as the swept-sine TF that we took before O1 (20783).
Setup is similar to the previous measurement, although in this case the PLL has a UGF around 20 kHz, so that the control signal going to the IFR can be read out directly in order to get the frequency deviation.
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During this test, there was some glitching of the rfam stabilization.
The attachment shows the rfam OOL monitor (bottom) and the digital excitation to the IFR (top). Note the control signal glitches that appear even in the absence of IFR drive.
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