[FieldTrip] Units powerspectrum time-frequency analysis

[Alexander Mentink]

Dear FieldTrip community,


I have a question regarding time-frequency analyses, it would be awesome if someone could help me out!


Does anyone perhaps know what the absolute units are of the TFRwave.powerspctrm that you get when performing a continuous wavelet transform:


cfg = [];
cfg.channel    = 'Cz';
cfg.method     = 'tfr';
cfg.width      = 7;
cfg.output     = 'pow';
cfg.foi        = 1:0.25:30;
cfg.toi        = -3:0.01:2.5;
TFRwave = ft_freqanalysis(cfg, trialdata);

cfg = [];
cfg.channel = 'Cz';
cfg.baseline     = [-0.5 -0.1];
cfg.baselinetype = 'absolute';
cfg.zlim         = 'maxabs';
cfg.xlim         = [-0.2 1.5];
cfg.showlabels   = 'yes';
figure
ft_singleplotTFR(cfg, TFRwave)


The single plot shows reliable results compared to the Hanning window method, however the values of the powerspectrum are in the hundred thousands (?) - see image attached.

This can't be uV^2/Hz, perhaps nV^2/Hz?


Thanks in advance!


Alex




Alexander Mentink
Centre for Human Drug Research
Zernikedreef 8
2333 CL Leiden
The Netherlands
T +31 (0) 71 7517166
amentink at chdr.nl
http://www.chdr.nl

Follow us:
[Twitter]<http://www.twitter.com/chdr_nl>       [LinkedIn] <http://www.linkedin.com/company/centre-for-human-drug-research>




-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20170831/8c45cf5e/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image5c5f52.PNG
Type: image/png
Size: 696 bytes
Desc: image5c5f52.PNG
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20170831/8c45cf5e/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image8e5b87.PNG
Type: image/png
Size: 648 bytes
Desc: image8e5b87.PNG
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20170831/8c45cf5e/attachment-0001.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: TFR_hanning_cm1_37.png
Type: image/png
Size: 30823 bytes
Desc: TFR_hanning_cm1_37.png
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20170831/8c45cf5e/attachment-0002.png>