Home > chronux_0.5 > pointbinned > mtdspectrumpb.m

mtdspectrumpb

PURPOSE ^

Multi-taper spectral derivative - binned point process

SYNOPSIS ^

function [dS,f]=mtdspectrumpb(data,phi,params)

DESCRIPTION ^

 Multi-taper spectral derivative - binned point process

 Usage:

 [dS,f]=mtdspectrumpb(data,phi,params)
 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]
       phi         (angle for evaluation of derivative) -- required.
                       e.g. phi=[0,pi/2] giving the time and frequency
                       derivatives
       params: structure with fields tapers, pad, Fs, fpass, 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
           trialave (average over trials when 1, don't average when 0) -
           optional. Default 0
 Output:
       dS       (derivative of the spectrum in form phi x frequency x channels/trials if trialave=0; in the form phi x frequency if trialave=1)
       f        (frequencies)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [dS,f]=mtdspectrumpb(data,phi,params)
0002 % Multi-taper spectral derivative - binned point process
0003 %
0004 % Usage:
0005 %
0006 % [dS,f]=mtdspectrumpb(data,phi,params)
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]
0015 %       phi         (angle for evaluation of derivative) -- required.
0016 %                       e.g. phi=[0,pi/2] giving the time and frequency
0017 %                       derivatives
0018 %       params: structure with fields tapers, pad, Fs, fpass, trialave
0019 %       -optional
0020 %           tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not
0021 %                                                 specified, use [NW K]=[3 5]
0022 %            pad            (padding factor for the FFT) - optional. Defaults to 0.
0023 %                       e.g. For N = 500, if PAD = 0, we pad the FFT
0024 %                       to 512 points; if PAD = 2, we pad the FFT
0025 %                       to 2048 points, etc.
0026 %           Fs   (sampling frequency) - optional. Default 1.
0027 %           fpass    (frequency band to be used in the calculation in the form
0028 %                                   [fmin fmax])- optional.
0029 %                                   Default all frequencies between 0 and
0030 %                                   Fs/2
0031 %           trialave (average over trials when 1, don't average when 0) -
0032 %           optional. Default 0
0033 % Output:
0034 %       dS       (derivative of the spectrum in form phi x frequency x channels/trials if trialave=0; in the form phi x frequency if trialave=1)
0035 %       f        (frequencies)
0036 
0037 if nargin < 2; error('Need data and angle'); end;
0038 if nargin < 3; params=[]; end;
0039 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
0040 
0041 N=size(data,1);
0042 nfft=2^(nextpow2(N)+pad);
0043 [f,findx]=getfgrid(Fs,nfft,fpass);
0044 tapers=dpsschk(tapers,N,Fs); % check tapers
0045 K=size(tapers,2);
0046 [J,Msp,Nsp]=mtfftpb(data,tapers,nfft);  
0047 J=J(findx,:,:);
0048 S=squeeze(mean(J(:,1:K-1,:).*conj(J(:,2:K,:)),2));
0049 if trialave; S=squeeze(mean(S,2)); end;
0050 nphi=length(phi);
0051 for p=1:nphi;
0052     dS(p,:,:)=real(exp(i*phi(p))*S);
0053 end;
0054 dS=squeeze(dS);

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