Multi-taper fourier transform - continuous data
Usage:
J=mtfftc(data,tapers,nfft,Fs) - all arguments required
Input:
data (in form samples x channels/trials or a single vector)
tapers (precalculated tapers from dpss)
nfft (length of padded data)
Fs (sampling frequency)
Output:
J (fft in form frequency index x taper index x channels/trials)0001 function J=mtfftc(data,tapers,nfft,Fs) 0002 % Multi-taper fourier transform - continuous data 0003 % 0004 % Usage: 0005 % J=mtfftc(data,tapers,nfft,Fs) - all arguments required 0006 % Input: 0007 % data (in form samples x channels/trials or a single vector) 0008 % tapers (precalculated tapers from dpss) 0009 % nfft (length of padded data) 0010 % Fs (sampling frequency) 0011 % 0012 % Output: 0013 % J (fft in form frequency index x taper index x channels/trials) 0014 if nargin < 4; error('Need all input arguments'); end; 0015 data=change_row_to_column(data); 0016 [NC,C]=size(data); % size of data 0017 [NK K]=size(tapers); % size of tapers 0018 if NK~=NC; error('length of tapers is incompatible with length of data'); end; 0019 tapers=tapers(:,:,ones(1,C)); % add channel indices to tapers 0020 data=data(:,:,ones(1,K)); % add taper indices to data 0021 data=permute(data,[1 3 2]); % reshape data to get dimensions to match those of tapers 0022 data_proj=data.*tapers; % product of data with tapers 0023 J=fft(data_proj,nfft)/Fs; % fft of projected data