Error in FREQANALYSIS

Grant McAuley gmcauley at LLU.EDU
Fri Mar 16 17:50:52 CET 2007


Thanks Robert,

I have decided to go with option b).

The 'WINDOW' information is enlightening and very helpful.

~ Grant

On Thu, 2007-03-15 at 13:53 +0100, Robert Oostenveld wrote:
> Hi Grant
>
> On 14 Mar 2007, at 22:12, Christian Hesse wrote:
> > Ahhh ... you're trying to do all of this without the signal
> > processing toolbox, aren't you. In that case I must apologize for
> > having given you slightly inaccurate info before: the DPSS and
> > WINDOW functions are from the signal processing toolbox.
> >
> > ...
> > Realistically speaking though, it seems to me that your best
> > options are basically a) to get the signal processing toolbox, or
> > b)  to just write your own matlab functions to estimate your power
> > spectra (about 3 lines of code) and then calculate your SEF and MF
> > measures (another few lines at most).
>
> with respect to option "b": I think the easiest is to replicate the
> WINDOW function from the signal preocessing toolbox. The dpss is
> difficult, but hanning, triangle, rectwin and some others are
> trivial. The WINDOW function is just a convenient wrapper function
> for various tapers. See at the bottom of this mail for the full help.
> The window replacement function to be written should behave as
>
>  >> tap = window('hanning', 10)
> tap =
>      0.0794
>      0.2923
>      0.5712
>      0.8274
>      0.9797
>      0.9797
>      0.8274
>      0.5712
>      0.2923
>      0.0794
>
>  >> tap = window('rectwin', 10)
> tap =
>       1
>       1
>       1
>       1
>       1
>       1
>       1
>       1
>       1
>       1
>
>  >> tap = window('triang', 10)
> tap =
>      0.1000
>      0.3000
>      0.5000
>      0.7000
>      0.9000
>      0.9000
>      0.7000
>      0.5000
>      0.3000
>      0.1000
>
> I hope that this suggestion helps,
> Robert
>
>
> ---------------
>
>  >> help window
> WINDOW Window function gateway.
>      WINDOW(@WNAME,N) returns an N-point window of type specified
>      by the function handle @WNAME in a column vector.  @WNAME can
>      be any valid window function name, for example:
>      @bartlett       - Bartlett window.
>      @barthannwin    - Modified Bartlett-Hanning window.
>      @blackman       - Blackman window.
>      @blackmanharris - Minimum 4-term Blackman-Harris window.
>      @bohmanwin      - Bohman window.
>      @chebwin        - Chebyshev window.
>      @flattopwin     - Flat Top window.
>      @gausswin       - Gaussian window.
>      @hamming        - Hamming window.
>      @hann           - Hann window.
>      @kaiser         - Kaiser window.
>      @nuttallwin     - Nuttall defined minimum 4-term Blackman-Harris
> window.
>      @parzenwin      - Parzen (de la Valle-Poussin) window.
>      @rectwin        - Rectangular window.
>      @tukeywin       - Tukey window.
>      @triang         - Triangular window.
>      WINDOW(@WNAME,N,OPT) designs the window with the optional input
> argument
>      specified in OPT. To see what the optional input arguments are,
> see the help
>      for the individual windows, for example, KAISER or CHEBWIN.
>      WINDOW launches the Window Design & Analysis Tool (WinTool).
>      EXAMPLE:
>         N  = 65;
>         w  = window(@blackmanharris,N);
>         w1 = window(@hamming,N);
>         w2 = window(@gausswin,N,2.5);
>         plot(1:N,[w,w1,w2]); axis([1 N 0 1]);
>         legend('Blackman-Harris','Hamming','Gaussian');
>
>      See also bartlett, barthannwin, blackman, blackmanharris,
> bohmanwin,
>               chebwin, gausswin, hamming, hann, kaiser, nuttallwin,
> parzenwin,
>               rectwin, triang, tukeywin, WINTOOL.
--
Grant McAuley
Research Affairs IS Support
Loma Linda University
909-558-1000 Ext 87750
gmcauley at llu.edu



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