Warning: Undefined variable $s in /var/www/public_html/osl/classes/DAO.php on line 959
NAOJ GW Elog Logbook
LOG-IN
Displaying report 1-1 of 1.
R&D (FilterCavity)
Print this report.
YuhangZhao - 09:09, Tuesday 13 March 2018 (693)Get code to link to this report
Charaterization of Filter Cavity
Participant: Yuefan, Yuhang, Eleonora

Yesterday, we did some characterization of our filter cavity.
1. Open Loop Transfer Function: The unity gain frequency is 10kHz and the phase margin is 39 degree. Actually this is not the practical case, we changed the gain of our loop. And we suspected this is because of the increase of circulating power.(Fig 1)
2. Calibration: We measured the calibration of green and infrared again. The calibration factor is similar with before.(Fig 2)
3. Error signal noise spectrum: We plot out the direct measurement and calibrated one together.(Fig 3 and 4)

You can use the data attached. They are not calibrated.
ger25k6 is green error signal with highest frequency 25600Hz(calibration factor is 2.6e-3V/Hz).
ier25k6 is infrared error signal with highest frequency 25600Hz(calibration factor is 6.3e-3V/Hz).
ol51k2 is open loop transfer function with highest frequency 51200Hz.
Images attached to this report
693_20180313004505_openlooptf.png 693_20180313005308_infraredcalibration.png 693_20180313005600_errorsignal.png 693_20180313005611_calierror.png
Non-image files attached to this report
Comments related to this report
Matteo Barsuglia - 19:51, Tuesday 13 March 2018 (695)

I've compared the error signals measured in the entry 690 with the new ones. There is something strange: now the error signal for the IR is 10 times smaller than before.