Error in FREQANALYSIS

Grant McAuley gmcauley at LLU.EDU
Fri Mar 16 17:30:51 CET 2007


Thanks Christian,

I will go with option b.

~ Grant

On Wed, 2007-03-14 at 22:12 +0100, Christian Hesse wrote:
> Hi Grant,
> 
> 
> 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.
> 
> 
> Having just had a play with FREQANALYSIS it turns out that in it's
> current version a taper must be specified (e.g., cfg.taper = 'none')
> gives an error. This means that you apparently cannot use FieldTrip
> (in its current form) to do simple, "no-frills" spectral estimation. I
> will have a closer look to see if we can change it so allow cfg.taper
> = 'none', since this means that you could apply your own taper to your
> data before using FREQANALYSIS or just leave it out.
> 
> 
> 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).
> 
> 
> Cheers,
> Christian
> 
> 
> 
> 
> 
> 
> > I am seeing an error in FREQANALYSIS (see output below).  It seems
> > centered around the 'cfg.tapper' field.  I have tried 'dpss',
> > 'hanning' (output below), and 'sine' (which gives an Out of Memory
> > Error).  (Not sure where to find info on WINDOW). 
> > 
> > 
> > 
> > 
> > My data is in a structure as described here: 
> > http://www2.ru.nl/fcdonders/fieldtrip/doku.php?id=fieldtrip:documentation:frequently_asked_questions
> > (How can I import my own dataformat?)
> > 
> > 
> > 
> > 
> > Relevant MATLAB output is below.
> > 
> > 
> > 
> > 
> > Pardon me if I am missing something obvious - this is new territory
> > for me.  Any ideas on what might be the problem?
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > % my data structure with example values
> > > > hv1_69
> > 
> > 
> > hv1_69 = 
> > 
> > 
> >       label: {2x1 cell}
> >     fsample: 200
> >       trial: {[2x48528 double]}
> >        time: {[1x48529 double]}
> > 
> > 
> > 
> > 
> > > > hv1_69.trial{1}(1,1:5)
> > 
> > 
> > ans =
> > 
> > 
> >     4.9460    4.2540    1.9510    0.0820    0.6380
> > 
> > 
> > > > hv1_69.time{1}(1,1:5)
> > 
> > 
> > ans =
> > 
> > 
> >          0    0.0050    0.0100    0.0150    0.0200
> > 
> > 
> > % here are cfg values
> > > > cfg
> > 
> > 
> > cfg = 
> > 
> > 
> >        output: 'pow'
> >        method: 'mtmfft'
> >     tapsmofrq: 4
> >           pad: 'maxperlen'
> >         taper: 'dpss'
> >        foilim: [0 100]
> > 
> > 
> > 
> > 
> > > > [freq] = freqanalysis(cfg, hv1_69);
> > ??? Undefined function or method 'dpss' for input arguments of type
> > 'double'.
> > 
> > 
> > Error in ==> freqanalysis_mtmfft>double_dpss at 560
> > tap = dpss(double(a), double(b), varargin{:});
> > 
> > 
> > Error in ==> freqanalysis_mtmfft at 387
> >       tap =
> > double_dpss(numdatbns,numdatbns*(cfg.tapsmofrq./data.fsample))';
> > 
> > 
> > Error in ==> freqanalysis at 193
> > [freq] = feval(sprintf('freqanalysis_ü·¢xÞ',lower(cfg.method)),
> > cfg, data);
> > 
> > 
> > 
> > 
> > 
> > 
> > % try different 'cfg.taper' value
> > > > cfg.taper = 'hanning';
> > > > [freq] = freqanalysis(cfg, hv1_69);
> > ??? Undefined function or method 'window' for input arguments of
> > type 'char'.
> > 
> > 
> > Error in ==> freqanalysis_mtmfft at 393
> >       tap = window(cfg.taper, numdatbns)';
> > 
> > 
> > Error in ==> freqanalysis at 193
> > [freq] = feval(sprintf('freqanalysis_ü·¢xÞ',lower(cfg.method)),
> > cfg, data);
> > 
> > 
> > 
> > 
> > %MATLAB version
> > > > version
> > 
> > 
> > ans =
> > 
> > 
> > 7.3.0.267 (R2006b)
> > 
> > 
> 
> ----------------------------------------------------------------------
> Christian Hesse, PhD, MIEEE
> 
> 
> F.C. Donders Centre for Cognitive Neuroimaging 
> P.O. Box 9101 
> NL-6500 HB Nijmegen 
> The Netherlands
> 
> 
> Tel.: +31 (0)24 36 68293
> Fax: +31 (0)24 36 10989
> 
> 
> Email: c.hesse at fcdonders.ru.nl
> Web: www.fcdonders.ru.nl
> ----------------------------------------------------------------------
> 
> 
> 
> 
> 
> 
> 
> 
-- 
Grant McAuley
Research Affairs IS Support
Loma Linda University
909-558-1000 Ext 87750
gmcauley at llu.edu



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