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Entry  Fri Nov 4 21:52:58 2011, Den, Update, Adaptive Filtering, coherence mirror_platform.jpgcoherence.jpgScreenshot-4.png
    Reply  Sun Nov 6 21:09:03 2011, rana, Update, Adaptive Filtering, coherence 
Message ID: 5825     Entry time: Sun Nov 6 21:09:03 2011     In reply to: 5816
Author: rana 
Type: Update 
Category: Adaptive Filtering 
Subject: coherence 


[Mirko, Den]

We still think about the coherence between seismic noise and mode cleaner length. We beleive that

The 'helping' trick is a good one: we should use our best guess for the stackTF and the pendulumTF and put it into the IIR filter bank to pre-filter the seismometer signals before they get to the MC mirrors. Also should remember that the signal we send to suppress the seismic motion is applied to the pendulum as a force, not a displacement.

The 3 Hz fast cutoff in the MC_F signal is a good clue. It means that at low frequencies, perhaps the noise source is going through a digital 3 Hz elliptic or Chebychev filter.

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