[FieldTrip] FFT on a single concatenate trial

[elisa filevich]

It did work, many thanks!

On Feb 4, 2014, at 10:44 AM, Eelke Spaak wrote:

> Dear Elisa,
> 
> Raw data is represented with time axes and trials in a cell array (one
> element per trial), so if you do
> 
> appended.trial = {appended.trial};
> appended.time = {appended.time};
> 
> it should work.
> 
> Best,
> Eelke
> 
> On 4 February 2014 10:36, elisa filevich <elisa.filevich at gmail.com> wrote:
>> Dear all,
>> 
>> I'm doing frequency tagging on relatively short epochs. My frequency
>> components are clearly there, but the signal-to-noise ratio is very low. In
>> order to improve SNR, I want to try to concatenate the individual trials
>> (with the appropriate epoch length to keep the frequency constant).
>> 
>> I simply concatenated all trial and timepoints vectors into a single trial
>> structure, and I now have may data in a structure that has the following
>> fields:
>> 
>> 
>> appended =
>> 
>>      label: {1x22 cell}
>>    fsample: 512
>>       elec: [1x1 struct]
>>      trial: [22x157990 single]
>>       time: [1x157990 double]
>> 
>> 
>> I then run the FFT below, and I get the following error:
>> 
>>   error('the data does not contain a dimord, but it also does not resemble
>> raw or component data');
>> 
>> Is it possible to run FFT on a single trial? Is there a way to work around
>> this?
>> 
>> Best
>> Elisa
>> 
>> 
>> cfg              = [];
>> cfg.output       = 'pow';
>> cfg.channel      = 'all';
>> cfg.method       = 'mtmfft';
>> cfg.taper        = 'hanning';
>> cfg.foi          = 5:.5:35;
>> cfg.keeptrials   = 'no';
>> FFThann          = ft_freqanalysis(cfg, epoched);
>> 
>> 
>> 
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