


Multi-taper fourier transform - continuous data
Usage:
J=mtfftc(data,tapers,nfft) - all arguments required
Input:
data (in form samples x channels/trials)
tapers (precalculated tapers from dpss)
nfft (length of padded data)
Output:
J (fft in form frequency index x taper index x channels/trials)

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