sudarshan.karki@LIGO.ORG - posted 20:40, Thursday 02 July 2015 - last comment - 11:50, Monday 25 January 2016(19434)
ISS Loop Transfer Function Measurement
Inner Loop
ISS Inner Loop has UGF of 22 KHz with a phase margin of about 50 degress. This was measured with variable gain set at 6 dB for the best phase margin. This is the normal operation settings for Inner Loop.
Outer Loop
Outer Loop has a UGF of 1 KHz ( designed for 4 KHz) with a phase margin of about 30 degrees. The variable gain was set at 40 dB (max available) and an additional gain stage(?) was switched on as well.
Also tried moving the the Inner loop gain to see if it shows any improvement on the outer loop but no luck.
TF Plots are attached.
Images attached to this report
Comments related to this report
These transfer function measurements were taken at ~10 W of PSL power.
The data used for the plot above is attached.
Non-image files attached to this comment
