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Message ID: 11458     Entry time: Wed Jul 29 11:15:21 2015
Author: Jessica 
Type: Summary 
Category: LSC 
Subject: PSDs of Arms with seismometer subtraction 

Ignacio and I downloaded data from the STS, GUR1, and GUR2 seismometers and from the mode cleaner and the x and y arms. The PSDs along the arms have the most noise at frequencies greater than 1 Hz, so we should focus on filtering in that area. The noise levels start dropping at around 30 Hz, but are still much higher than is seen at frequencies below 1 Hz. However, because the spectra is so low at frequencies below that, Wiener filtering alone injected a significant amount of noise into those frequencies and did not do much to reduce the noise at higher frequencies. Pre-filtering will be required, and I have started implementing a pre-filter, but with no improvements yet. So far, I have tried making a bandpass filter, but a highpass filter may be ideal in this case because so much of the noise is above 1 Hz. 

Attachment 1: Arms_PSD.png  119 kB  | Hide | Hide all
Attachment 2: XArm_PSD.png  24 kB  | Hide | Hide all
Attachment 3: YArm_PSD.png  23 kB  | Hide | Hide all
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