Home > chronux_1_50 > continuous > cohgramc.m

cohgramc

PURPOSE ^

Multi-taper time-frequency coherence,cross-spectrum and individual spectra - continuous processes

SYNOPSIS ^

function [C,phi,S12,S1,S2,t,f,confC,phistd,Cerr]=cohgramc(data1,data2,movingwin,params)

DESCRIPTION ^

 Multi-taper time-frequency coherence,cross-spectrum and individual spectra - continuous processes

 Usage:

 [C,phi,S12,S1,S2,t,f,confC,phistd,Cerr]=cohgramc(data1,data2,movingwin,params)
 Input: 
 Note units have to be consistent. Thus, if movingwin is in seconds, Fs
 has to be in Hz. see chronux.m for more information.

       data1 (in form samples x trials) -- required
       data2 (in form samples x trials) -- required
       movingwin (in the form [window winstep] -- 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 when 1, don't average when 0) - optional. Default 0
 Output:
       C (magnitude of coherency time x frequencies x trials for trialave=0; time x frequency for trialave=1)
       phi (phase of coherency time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
       S12 (cross spectrum - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
       S1 (spectrum 1 - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
       S2 (spectrum 2 - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
       t (time)
       f (frequencies)
       confC (confidence level for C at 1-p %) - only for err(1)>=1
       phistd - theoretical/jackknife (depending on err(1)=1/err(1)=2) standard deviation for phi - Note that 
                phi + 2 phistd and phi - 2 phistd will give 95% confidence
                bands for phi - only for err(1)>=1 
       Cerr  (Jackknife error bars for C - use only for Jackknife - err(1)=2)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [C,phi,S12,S1,S2,t,f,confC,phistd,Cerr]=cohgramc(data1,data2,movingwin,params)
0002 % Multi-taper time-frequency coherence,cross-spectrum and individual spectra - continuous processes
0003 %
0004 % Usage:
0005 %
0006 % [C,phi,S12,S1,S2,t,f,confC,phistd,Cerr]=cohgramc(data1,data2,movingwin,params)
0007 % Input:
0008 % Note units have to be consistent. Thus, if movingwin is in seconds, Fs
0009 % has to be in Hz. see chronux.m for more information.
0010 %
0011 %       data1 (in form samples x trials) -- required
0012 %       data2 (in form samples x trials) -- required
0013 %       movingwin (in the form [window winstep] -- required
0014 %       params: structure with fields tapers, pad, Fs, fpass, err, trialave
0015 %       - optional
0016 %           tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not
0017 %                                                 specified, use [NW K]=[3 5]
0018 %            pad            (padding factor for the FFT) - optional (can take values -1,0,1,2...).
0019 %                    -1 corresponds to no padding, 0 corresponds to padding
0020 %                    to the next highest power of 2 etc.
0021 %                       e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
0022 %                       to 512 points, if pad=1, we pad to 1024 points etc.
0023 %                       Defaults to 0.
0024 %           Fs   (sampling frequency) - optional. Default 1.
0025 %           fpass    (frequency band to be used in the calculation in the form
0026 %                                   [fmin fmax])- optional.
0027 %                                   Default all frequencies between 0 and Fs/2
0028 %           err  (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
0029 %                                   [0 p] or 0 - no error bars) - optional. Default 0.
0030 %           trialave (average over trials when 1, don't average when 0) - optional. Default 0
0031 % Output:
0032 %       C (magnitude of coherency time x frequencies x trials for trialave=0; time x frequency for trialave=1)
0033 %       phi (phase of coherency time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
0034 %       S12 (cross spectrum - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
0035 %       S1 (spectrum 1 - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
0036 %       S2 (spectrum 2 - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
0037 %       t (time)
0038 %       f (frequencies)
0039 %       confC (confidence level for C at 1-p %) - only for err(1)>=1
0040 %       phistd - theoretical/jackknife (depending on err(1)=1/err(1)=2) standard deviation for phi - Note that
0041 %                phi + 2 phistd and phi - 2 phistd will give 95% confidence
0042 %                bands for phi - only for err(1)>=1
0043 %       Cerr  (Jackknife error bars for C - use only for Jackknife - err(1)=2)
0044 
0045 if nargin < 3; error('Need data1 and data2 and window parameters'); end;
0046 if nargin < 4; params=[];end;
0047 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
0048 
0049 if nargout > 9 && err(1)~=2; 
0050     error('Cerr computed only for Jackknife. Correct inputs and run again');
0051 end;
0052 if nargout >= 7 && err(1)==0;
0053 %   Errors computed only if err(1) is nonzero. Need to change params and run again.
0054     error('When errors are desired, err(1) has to be non-zero.');
0055 end;
0056 [N,Ch]=check_consistency(data1,data2);
0057 
0058 Nwin=round(Fs*movingwin(1)); % number of samples in window
0059 Nstep=round(movingwin(2)*Fs); % number of samples to step through
0060 nfft=max(2^(nextpow2(Nwin)+pad),Nwin);
0061 f=getfgrid(Fs,nfft,fpass); 
0062 Nf=length(f);
0063 params.tapers=dpsschk(tapers,Nwin,Fs); % check tapers
0064 
0065 winstart=1:Nstep:N-Nwin+1;
0066 nw=length(winstart);
0067 if trialave;
0068    C=zeros(nw,Nf);
0069    S12=zeros(nw,Nf);
0070    S1=zeros(nw,Nf);
0071    S2=zeros(nw,Nf);
0072    phi=zeros(nw,Nf);
0073    Cerr=zeros(2,nw,Nf);
0074 %    phierr=zeros(2,nw,Nf);
0075    phistd=zeros(nw,Nf);
0076 else
0077    C=zeros(nw,Nf,Ch);
0078    S12=zeros(nw,Nf,Ch);
0079    S1=zeros(nw,Nf,Ch);
0080    S2=zeros(nw,Nf,Ch);
0081    phi=zeros(nw,Nf,Ch);
0082    Cerr=zeros(2,nw,Nf,Ch);
0083 %    phierr=zeros(2,nw,Nf,Ch);
0084    phistd=zeros(nw,Nf,Ch);
0085 end;
0086 
0087 for n=1:nw;
0088    indx=winstart(n):winstart(n)+Nwin-1;
0089    datawin1=data1(indx,:);datawin2=data2(indx,:);
0090    if nargout==10;
0091      [c,ph,s12,s1,s2,f,confc,phie,cerr]=coherencyc(datawin1,datawin2,params);
0092 %      phierr(1,n,:,:)=squeeze(phie(1,:,:));
0093 %      phierr(2,n,:,:)=squeeze(phie(2,:,:));
0094      phistd(n,:,:)=phie;
0095      Cerr(1,n,:,:)=squeeze(cerr(1,:,:));
0096      Cerr(2,n,:,:)=squeeze(cerr(2,:,:));
0097    elseif nargout==9;
0098      [c,ph,s12,s1,s2,f,confc,phie]=coherencyc(datawin1,datawin2,params);
0099 %      phierr(1,n,:,:)=squeeze(phie(1,:,:));
0100 %      phierr(2,n,:,:)=squeeze(phie(2,:,:));
0101       phistd(n,:,:)=phie;
0102    else
0103      [c,ph,s12,s1,s2,f]=coherencyc(datawin1,datawin2,params);
0104    end;
0105    C(n,:,:)=c;
0106    S12(n,:,:)=s12;
0107    S1(n,:,:)=s1;
0108    S2(n,:,:)=s2;
0109    phi(n,:,:)=ph;
0110 end;
0111 C=squeeze(C); phi=squeeze(phi);S12=squeeze(S12); S1=squeeze(S1); S2=squeeze(S2);
0112 if nargout > 8; confC=confc; end;
0113 if nargout==10;Cerr=squeeze(Cerr);end;
0114 % if nargout>=9; phierr=squeeze(phierr);end
0115 if nargout>=9; phistd=squeeze(phistd);end
0116 winmid=winstart+round(Nwin/2);
0117 t=winmid/Fs;

Generated on Mon 09-Oct-2006 00:54:52 by m2html © 2003