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Entry  Sun Nov 2 20:44:58 2008, rana, Update, ASS, Wiener Filter performance over 5 hours f.pngf1.png
    Reply  Mon Nov 3 22:35:40 2008, rana, Update, ASS, Wiener Filter performance over 5 hours DAQ.pdf
    Reply  Tue Nov 4 00:47:53 2008, rana, Update, ASS, Wiener Filter performance over 5 hours f2.pngf.png
Message ID: 1105     Entry time: Sun Nov 2 20:44:58 2008     Reply to this: 1111   1112
Author: rana 
Type: Update 
Category: ASS 
Subject: Wiener Filter performance over 5 hours 
I took one 2 hour stretch of data to calculate a MISO Wiener filter to subtract the Ranger seismometer
and the 6 Wilcoxon accelerometers from the IOO-MC_L channel. I then used that static filter to calculate
the residual of the subtraction in 10 minute increments for 5 hours. The filter was calculated based upon
the first 2 hours of the stretch.

The MC lock stretch is from Oct 31 03:00 UTC (I think that we are -8 hours from UTC, but the DST confounds me).
So its from this past Thursday night.

I wrote a script (/users/rana/mat/wiener/mcl_comp.m) which takes the static filter and does a bunch of loops
of subtraction to get a residual power spectrum for each 10 minute interval.

In the attached PNG, you can see the result. The legend is in units of minutes from the initial t0 = 03:00 UTC.

BLACK-DASHED -- MCL spectrum before subtraction

I have also used dashed lines for some of the other traces where there is an excess above the unsubtracted data.
Other than those few times, the rest are all basically the same; this indicates that we can do fine with a very
slow adaptation time for the feed-forward filters
-- a few hours of a time constant is not so bad.

After making the plot I noticed that the Ranger signal was totally railed and junky during this time.
This probably explains the terrible performance below 1 Hz (where are those Guralps?)

The second attached image is the same but in spectrogram form.
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Attachment 2: f1.png  345 kB  Uploaded Sun Nov 2 23:24:39 2008  | Hide | Hide all
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