Time frequency Analysis!

Muthuraman Muthuraman muthuraman10 at HOTMAIL.COM
Wed Jan 31 11:03:41 CET 2007

Hello ,

Thankyou for correcting some of the errors in the parameters

Do you get a warning when executing the
I do get any warning while executing the singleplotTFR function

If there are only nans in your TFRmult, then I don't get it, because your
configuration looks OK to me?
I use now Fieldtrip 20070109 version

i have changed the code as you have suggested

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});
data         = appenddata([],data,emg);

cfg.channel    = channelselection({'all' 'M1'}, data.label);

cfg.baselinetype=[0.1 1.0];
cfg.zlim=[-2e-27 2e-27];
I get only one warning that is the analysis uses one taper

But now after changing the code i get some values and all other values to be
Nan's in the 'mtmconvol' function
I have attached the Figure with this mail which i get from the analysis
I will send the cnt file through yousentit.com
Please let me know what could be the problems still in the code

Thanking you

with regards

>From: Jan Mathijs Schoffelen <Jan.Schoffelen at FCDONDERS.RU.NL>
>Reply-To: FieldTrip discussion list <FIELDTRIP at NIC.SURFNET.NL>
>Subject: Re: [FIELDTRIP] Time frequency Analysis!
>Date: Tue, 30 Jan 2007 17:34:44 +0100
>Dear Muthuraman,
>It pleases us that we finally got you to try multi-tapers for your spectral
>analysis! Sometimes it's hard convincing people, but in the end...
>First of all there's a typo in your configuration for the frequency
>analysis; this does not explain your results, but as an extra service to
>I'd like to point it out. You specify cfg.ouput, where I guess you mean
>cfg.output. Moreover, since you have an EMG-channel in your data, you might
>be interested in computing the coherence, but therefore you have to specify
>cfg.output = 'powandcsd'.
>Regarding your nans: did you check whether there are any numbers in
>TFRmult.powspctrm. If this is the case, your problem most likely arises in
>the plotting. You specify cfg.baselinetype = 'relative', but you do not
>specify the baseline-interval. Do you get a warning when executing the
>If there are only nans in your TFRmult, then I don't get it, because your
>configuration looks OK to me?
>By the way, which version of fieldtrip are you using? If you are using an
>old one, it might be worthwile to download the latest version (there's a
>daily update on the FTP-server, you can get there through the
>fieldtrip-website), and try the script again (with the small changes
>-----Original Message-----
>From: FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] On Behalf
>Of Muthuraman Muthuraman
>Sent: Tuesday, January 30, 2007 3:40 PM
>Subject: [FIELDTRIP] Time frequency Analysis!
>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});
>data         = appenddata([],data,emg);
>cfg.channel    = channelselection({'all' 'M1'}, data.label);
>cfg.zlim=[-2e-27 2e-27];
>Thanking you
>With regards
>Tickle your funny bone with Rahul Phondke

Catch all the cricketing action right here. Live score, match reports,
photos et al. http://content.msn.co.in/Sports/Cricket/Default.aspx
-------------- next part --------------
A non-text attachment was scrubbed...
Name: pd0306-timefrequencyplot.fig
Type: application/octet-stream
Size: 4645 bytes
Desc: not available
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20070131/ec9f3dc6/attachment-0002.obj>

More information about the fieldtrip mailing list