


Multi-taper spectrum - continuous process
Usage:
[S,f,Serr]=mtspectrumc(data,params)
Input:
Note units have to be consistent. See chronux.m for more information.
data (in form samples x channels/trials) -- required
params: structure with fields tapers, pad, Fs, fpass, err, trialave
-optional
tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not
specified, use [NW K]=[3 5]
pad (padding factor for the FFT) - optional (can take values -1,0,1,2...).
-1 corresponds to no padding, 0 corresponds to padding
to the next highest power of 2 etc.
e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
to 512 points, if pad=1, we pad to 1024 points etc.
Defaults to 0.
Fs (sampling frequency) - optional. Default 1.
fpass (frequency band to be used in the calculation in the form
[fmin fmax])- optional.
Default all frequencies between 0 and Fs/2
err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
[0 p] or 0 - no error bars) - optional. Default 0.
trialave (average over trials/channels when 1, don't average when 0) - optional. Default 0
Output:
S (spectrum in form frequency x channels/trials if trialave=0; in the form frequency if trialave=1)
f (frequencies)
Serr (error bars) only for err(1)>=1

0001 function [S,f,Serr]=mtspectrumc(data,params) 0002 % Multi-taper spectrum - continuous process 0003 % 0004 % Usage: 0005 % 0006 % [S,f,Serr]=mtspectrumc(data,params) 0007 % Input: 0008 % Note units have to be consistent. See chronux.m for more information. 0009 % data (in form samples x channels/trials) -- required 0010 % params: structure with fields tapers, pad, Fs, fpass, err, trialave 0011 % -optional 0012 % tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 0013 % specified, use [NW K]=[3 5] 0014 % pad (padding factor for the FFT) - optional (can take values -1,0,1,2...). 0015 % -1 corresponds to no padding, 0 corresponds to padding 0016 % to the next highest power of 2 etc. 0017 % e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT 0018 % to 512 points, if pad=1, we pad to 1024 points etc. 0019 % Defaults to 0. 0020 % Fs (sampling frequency) - optional. Default 1. 0021 % fpass (frequency band to be used in the calculation in the form 0022 % [fmin fmax])- optional. 0023 % Default all frequencies between 0 and Fs/2 0024 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0025 % [0 p] or 0 - no error bars) - optional. Default 0. 0026 % trialave (average over trials/channels when 1, don't average when 0) - optional. Default 0 0027 % Output: 0028 % S (spectrum in form frequency x channels/trials if trialave=0; in the form frequency if trialave=1) 0029 % f (frequencies) 0030 % Serr (error bars) only for err(1)>=1 0031 0032 if nargin < 1; error('Need data'); end; 0033 if nargin < 2; params=[]; end; 0034 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0035 if nargout > 2 && err(1)==0; 0036 % Cannot compute error bars with err(1)=0. Change params and run again. 0037 error('When Serr is desired, err(1) has to be non-zero.'); 0038 end; 0039 data=change_row_to_column(data); 0040 N=size(data,1); 0041 nfft=max(2^(nextpow2(N)+pad),N); 0042 [f,findx]=getfgrid(Fs,nfft,fpass); 0043 tapers=dpsschk(tapers,N,Fs); % check tapers 0044 J=mtfftc(data,tapers,nfft,Fs); 0045 J=J(findx,:,:); 0046 S=squeeze(mean(conj(J).*J,2)); 0047 if trialave; S=squeeze(mean(S,2));end; 0048 if nargout==3; 0049 Serr=specerr(S,J,err,trialave); 0050 end;