Home > chronux_0.5 > 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,phierr,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,phierr,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. 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 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
       phierr (error bars 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,phierr,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,phierr,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. Defaults to 0.
0019 %                       e.g. For N = 500, if PAD = 0, we pad the FFT
0020 %                       to 512 points; if PAD = 2, we pad the FFT
0021 %                       to 2048 points, etc.
0022 %           Fs   (sampling frequency) - optional. Default 1.
0023 %           fpass    (frequency band to be used in the calculation in the form
0024 %                                   [fmin fmax])- optional.
0025 %                                   Default all frequencies between 0 and Fs/2
0026 %           err  (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
0027 %                                   [0 p] or 0 - no error bars) - optional. Default 0.
0028 %           trialave (average over trials when 1, don't average when 0) - optional. Default 0
0029 % Output:
0030 %       C (magnitude of coherency time x frequencies x trials for trialave=0; time x frequency for trialave=1)
0031 %       phi (phase of coherency time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
0032 %       S12 (cross spectrum - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
0033 %       S1 (spectrum 1 - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
0034 %       S2 (spectrum 2 - time x frequencies x trials for no trial averaging; time x frequency for trialave=1)
0035 %       t (time)
0036 %       f (frequencies)
0037 %       confC (confidence level for C at 1-p %) - only for err(1)>=1
0038 %       phierr (error bars for phi) - only for err(1)>=1
0039 %       Cerr  (Jackknife error bars for C - use only for Jackknife - err(1)=2)
0040 
0041 if nargin < 3; error('Need data1 and data2 and window parameters'); end;
0042 if nargin < 4; params=[];end;
0043 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
0044 if nargout > 9 && err(1)~=2; 
0045     error('Cerr computed only for Jackknife. Correct inputs and run again');
0046 end;
0047 if nargout >= 7 && err(1)==0;
0048 %   Errors computed only if err(1) is nonzero. Need to change params and run again.
0049     error('When errors are desired, err(1) has to be non-zero.');
0050 end;
0051 [N1,C1,N2,C2]=check_consistency(data1,data2);
0052 N=N1;
0053 
0054 Nwin=round(Fs*movingwin(1)); % number of samples in window
0055 Nstep=round(movingwin(2)*Fs); % number of samples to step through
0056 nfft=2^(nextpow2(Nwin)+pad);
0057 f=getfgrid(Fs,nfft,fpass); 
0058 params.tapers=dpsschk(tapers,Nwin,Fs); % check tapers
0059 
0060 winstart=1:Nstep:N-Nwin+1;
0061 nw=length(winstart);
0062 for n=1:nw;
0063    indx=winstart(n):winstart(n)+Nwin-1;
0064    datawin1=data1(indx,:);datawin2=data2(indx,:);
0065    if nargout==10;
0066      [c,ph,s12,s1,s2,f,confc,phie,cerr]=coherencyc(datawin1,datawin2,params);
0067      confC=confc;
0068      phierr(1,n,:,:)=squeeze(phie(1,:,:));
0069      phierr(2,n,:,:)=squeeze(phie(2,:,:));
0070      Cerr(1,n,:,:)=squeeze(cerr(1,:,:));
0071      Cerr(2,n,:,:)=squeeze(cerr(2,:,:));
0072    elseif nargout==9;
0073      [c,ph,s12,s1,s2,f,confc,phie]=coherencyc(datawin1,datawin2,params);
0074      confC=confc;
0075      phierr(1,n,:,:)=squeeze(phie(1,:,:));
0076      phierr(2,n,:,:)=squeeze(phie(2,:,:));
0077    else
0078      [c,ph,s12,s1,s2,f]=coherencyc(datawin1,datawin2,params);
0079    end;
0080    C(n,:,:)=c;
0081    S12(n,:,:)=s12;
0082    S1(n,:,:)=s1;
0083    S2(n,:,:)=s2;
0084    phi(n,:,:)=ph;
0085 end;
0086 C=squeeze(C); phi=squeeze(phi);S12=squeeze(S12); S1=squeeze(S1); S2=squeeze(S2);
0087 if nargout==10;Cerr=squeeze(Cerr);end;
0088 if nargout>=9; phierr=squeeze(phierr);end
0089 winmid=winstart+round(Nwin/2);
0090 t=winmid/Fs;

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