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Entry  Sat Jan 29 03:13:44 2011, rana, Update, WienerFiltering, Improvement in H1 Wiener FF prediction by using weights and taps darmweight.pngdarm3000.png
    Reply  Mon Jan 31 10:31:30 2011, josephb, Update, WienerFiltering, Improvement in H1 Wiener FF prediction by using weights and taps 
Message ID: 4226     Entry time: Sat Jan 29 03:13:44 2011     Reply to this: 4231
Author: rana 
Type: Update 
Category: WienerFiltering 
Subject: Improvement in H1 Wiener FF prediction by using weights and taps 

(Jenne, Rana)

Tonight we noticed that there were significant improvements to be had in the predicted DARM Wiener filtering FF performance by using weighting filters and more taps in the FIR filter.

The plots below tell the story:

The first one shows the improvement in the residual (black & blue) by applying a weighting filter. The weight filter tilts the spectrum up at HF and applies and all real pole BP from 10-20 Hz.

The second plot shows the improvement gotten by using 3000 instead of 2000 taps for the Wiener filter. With the larger number of taps we not only get the big improvement at LF, but also some beefy reduction in the higher frequency stack modes and the LOS roll mode.

I'm not sure why we haven't run across this before; the weighting filter was arrived at today by just iterating by hand on the placement of poles and zeros until the trace looked nice.

Jenne is going to run this new filter on the S5-month that we have been using for stationarity testing.

* Some notes:

** this Wiener stuff is faster, by far, on rossa than either megatron or rosalba or my laptop. More than a factor of 3.

*** there is a bug with Macports/Matlab - if you get fftw3 with Macports, it sets itself as the right version to use. This confuses matlab in some cases.

     if you get the error about libfftw3.dylib, whe trying fft in matlab after installing macports, then you can fix it by setting the Matlab lib/ path with the fftw libraries to be ahead of /opt/local/lib in the LD_LIBRARY_PATH in your .cshrc.

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