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mtspectrumc

PURPOSE ^

Multi-taper spectrum - continuous process

SYNOPSIS ^

function [S,f,Serr]=mtspectrumc(data,params)

DESCRIPTION ^

 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. Defaults to 0.  
                       e.g. For N = 500, if PAD = 0, we pad the FFT 
                       to 512 points; if PAD = 2, we pad the FFT
                       to 2048 points, etc.
           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

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

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. Defaults to 0.
0015 %                       e.g. For N = 500, if PAD = 0, we pad the FFT
0016 %                       to 512 points; if PAD = 2, we pad the FFT
0017 %                       to 2048 points, etc.
0018 %           Fs   (sampling frequency) - optional. Default 1.
0019 %           fpass    (frequency band to be used in the calculation in the form
0020 %                                   [fmin fmax])- optional.
0021 %                                   Default all frequencies between 0 and Fs/2
0022 %           err  (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
0023 %                                   [0 p] or 0 - no error bars) - optional. Default 0.
0024 %           trialave (average over trials/channels when 1, don't average when 0) - optional. Default 0
0025 % Output:
0026 %       S       (spectrum in form frequency x channels/trials if trialave=0; in the form frequency if trialave=1)
0027 %       f       (frequencies)
0028 %       Serr    (error bars) only for err(1)>=1
0029 
0030 if nargin < 1; error('Need data'); end;
0031 if nargin < 2; params=[]; end;
0032 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
0033 if nargout > 2 && err(1)==0; 
0034 %   Cannot compute error bars with err(1)=0. Change params and run again.
0035     error('When Serr is desired, err(1) has to be non-zero.');
0036 end;
0037 data=change_row_to_column(data);
0038 N=size(data,1);
0039 nfft=2^(nextpow2(N)+pad);
0040 [f,findx]=getfgrid(Fs,nfft,fpass); 
0041 tapers=dpsschk(tapers,N,Fs); % check tapers
0042 J=mtfftc(data,tapers,nfft,Fs);
0043 J=J(findx,:,:);
0044 S=squeeze(mean(conj(J).*J,2));
0045 if trialave; S=squeeze(mean(S,2));end;
0046 if nargout==3; 
0047    Serr=specerr(S,J,err,trialave);
0048 end;

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