mtdspectrumc

PURPOSE ^

Multi-taper frequency derivative of the spectrum - continuous process

SYNOPSIS ^

function [dS,f]=mtdspectrumc(data,tapers,phi,pad,Fs,fpass,trialave)

DESCRIPTION ^

 Multi-taper frequency derivative of the spectrum - continuous process

 Usage:

 [dS,f]=mtdspectrumc(data,tapers,phi,pad,Fs,fpass,trialave)
 Input: 
   Note that all times can be in arbitrary units. But the units have to be
   consistent. So, if E is in secs, win, t have to be in secs, and Fs has to
   be Hz. If E is in samples, so are win and t, and Fs=1. In case of spike
   times, the units have to be consistent with the units of data as well.
       data        (in form samples x channels/trials) -- required
       tapers      (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 
                                                 specified, use [NW K]=[3 5]7
       phi         (angle for evaluation of derivative) -- optional.
                       Default phi=[0,pi/2] giving the time and frequency derivatives
        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
       trialave (average over trials when 1, don't average when 0) - optional. Default 0
 Output:
       dS       (spectrum in form angle x frequency x taper index x channels/trials)
       f        (frequencies)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [dS,f]=mtdspectrumc(data,tapers,phi,pad,Fs,fpass,trialave)
0002 % Multi-taper frequency derivative of the spectrum - continuous process
0003 %
0004 % Usage:
0005 %
0006 % [dS,f]=mtdspectrumc(data,tapers,phi,pad,Fs,fpass,trialave)
0007 % Input:
0008 %   Note that all times can be in arbitrary units. But the units have to be
0009 %   consistent. So, if E is in secs, win, t have to be in secs, and Fs has to
0010 %   be Hz. If E is in samples, so are win and t, and Fs=1. In case of spike
0011 %   times, the units have to be consistent with the units of data as well.
0012 %       data        (in form samples x channels/trials) -- required
0013 %       tapers      (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not
0014 %                                                 specified, use [NW K]=[3 5]7
0015 %       phi         (angle for evaluation of derivative) -- optional.
0016 %                       Default phi=[0,pi/2] giving the time and frequency derivatives
0017 %        pad            (padding factor for the FFT) - optional. Defaults to 0.
0018 %                       e.g. For N = 500, if PAD = 0, we pad the FFT
0019 %                       to 512 points; if PAD = 2, we pad the FFT
0020 %                       to 2048 points, etc.
0021 %       Fs   (sampling frequency) - optional. Default 1.
0022 %       fpass    (frequency band to be used in the calculation in the form
0023 %                                   [fmin fmax])- optional.
0024 %                                   Default all frequencies between 0 and Fs/2
0025 %       trialave (average over trials when 1, don't average when 0) - optional. Default 0
0026 % Output:
0027 %       dS       (spectrum in form angle x frequency x taper index x channels/trials)
0028 %       f        (frequencies)
0029 
0030 if nargin < 1; error('Need data'); end;
0031 if nargin < 2; tapers=[3 5]; end;
0032 if nargin < 3; phi=[0 pi/2];end;
0033 if nargin < 4;pad=0;end;
0034 if nargin < 5; Fs=1; end;
0035 if nargin < 6; fpass=[0 Fs/2]; end;
0036 if nargin < 7; trialave=0; end;
0037 
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 K=size(tapers,2);
0043 J=mtfftc(data,tapers,nfft,Fs);
0044 J=J(findx,:,:);
0045 S=squeeze(mean(J(:,1:K-1,:).*conj(J(:,2:K,:)),2));
0046 if trialave; S=squeeze(mean(S,2));end;
0047 nphi=length(phi);
0048 for p=1:nphi;
0049     dS(p,:,:)=real(exp(i*phi(p))*S);
0050 end;
0051 dS=squeeze(dS);

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