Time frequency Analysis!

Muthuraman Muthuraman muthuraman10 at HOTMAIL.COM
Tue Jan 30 15:39:33 CET 2007


Hello Fieldtrippers,

I have question regarding the Time-Frequency analysis using tapers,
'mtmconvol' or time frequency analysis using wavelets 'wltconvol'
these are the parameters i use, i get all the values to be Nan's
Is there something wrong which i need to change in the parameters for the
timefrequency analysis

hdr     = read_fcdc_header('pd_mof_tr0_c_0306.cnt');
emgindx = strmatch('M', hdr.label);
rstindx = setdiff(1:length(hdr.label),emgindx);

trl = [];
trl(:,1) = [21:1000:74520-1000]';
trl(:,2) = [1020:1000:74520]';
trl(:,3) = 0;


cfg.dataset = 'pd_mof_tr0_c_0306.cnt';
cfg.trl     = trl;
cfg.channel = hdr.label(rstindx);
cfg.blc     = 'yes';
data        = preprocessing(cfg);

cfg.channel  = hdr.label(emgindx);
cfg.hpfilter = 'yes';
cfg.hpfreq   = 10;
cfg.rectify  = 'yes';
emg          = preprocessing(cfg);

for j = 1:length(emg.trial)
  emg.trial{j} = blc(emg.trial{j});
end
data         = appenddata([],data,emg);

%---freqanalysis-mtmconvol
cfg=[];
cfg.ouput='pow';
cfg.sgn='data';
cfg.method='mtmconvol';
cfg.channel    = channelselection({'all' 'M1'}, data.label);
cfg.foi=2:2:30;
numfoi=length(cfg.foi);
cfg.t_ftimwin=zeros(1,numfoi);
cfg.t_ftimwin(:)=0.5;
cfg.tapsmofrq=zeros(1,numfoi);
cfg.tapsmofrq(:)=10;
cfg.toi=-0.5:0.05:1.0;
cfg.taper='dpss';
cfg.pad=2;
cfg.keeptrials='no';
TFRmult=freqanalysis(cfg,data);

%---Plotting
cfg=[];
cfg.baselinetype='relative';
cfg.zlim=[-2e-27 2e-27];
cfg.showlabels='yes';
cfg.channel='C3';
singleplotTFR(cfg,TFRmult);


Thanking you

With regards
M.Muthuraman.

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