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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 (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

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 (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;

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