


Multi-taper coherency - continuous process
Usage:
[C,phi,f,confC,phierr,Cerr]=coherencyc(data1,data2,tapers,nfft,Fs,fpass,err,trialave)
Input:
Note units have to be consistent. See chronux.m for more information.
data1 (in form samples x channels/trials) -- required
data2 (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]
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 (abs of coherency frequency index x channels/trials)
phi (phase of coherency frequency x channels/trials)
f (frequencies)
confC (confidence level for c at 1-p %)
phierr (error bars for phi)
Cerr (Jackknife error bars for C - use only for Jackknife)

0001 function [C,phi,f,confC,phierr,Cerr]=coherencyc(data1,data2,tapers,pad,Fs,fpass,err,trialave) 0002 % Multi-taper coherency - continuous process 0003 % 0004 % Usage: 0005 % [C,phi,f,confC,phierr,Cerr]=coherencyc(data1,data2,tapers,nfft,Fs,fpass,err,trialave) 0006 % Input: 0007 % Note units have to be consistent. See chronux.m for more information. 0008 % data1 (in form samples x channels/trials) -- required 0009 % data2 (in form samples x channels/trials) -- required 0010 % tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 0011 % specified, use [NW K]=[3 5] 0012 % pad (padding factor for the FFT) - optional. Defaults to 0. 0013 % e.g. For N = 500, if PAD = 0, we pad the FFT 0014 % to 512 points; if PAD = 2, we pad the FFT 0015 % to 2048 points, etc. 0016 % Fs (sampling frequency) - optional. Default 1. 0017 % fpass (frequency band to be used in the calculation in the form 0018 % [fmin fmax])- optional. 0019 % Default all frequencies between 0 and Fs/2 0020 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0021 % [0 p] or 0 - no error bars) - optional. Default 0. 0022 % trialave (average over trials when 1, don't average when 0) - optional. Default 0 0023 % Output: 0024 % C (abs of coherency frequency index x channels/trials) 0025 % phi (phase of coherency frequency x channels/trials) 0026 % f (frequencies) 0027 % confC (confidence level for c at 1-p %) 0028 % phierr (error bars for phi) 0029 % Cerr (Jackknife error bars for C - use only for Jackknife) 0030 if nargin < 2; error('Need data1 and data2'); end;warning off MATLAB:divideByZero 0031 N=size(data1,1); 0032 if nargin < 3; tapers=[3 5]; 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; err=0; end; 0037 if nargin<8; trialave=0;end; 0038 if nargout > 5 & err(1)~=2; 0039 error('Cerr computed only for Jackknife. Correct inputs and run again'); 0040 end; 0041 0042 if isempty(tapers); tapers=[3 5]; end; 0043 if isempty(pad);pad=0;end; 0044 if isempty(Fs); Fs=1; end; 0045 if isempty(fpass); fpass=[0 Fs/2]; end; 0046 if isempty(err); err=0; end; 0047 if isempty(trialave); trialave=0;end; 0048 0049 nfft=2^(nextpow2(N)+pad); 0050 [f,findx]=getfgrid(Fs,nfft,fpass); 0051 tapers=dpsschk(tapers,N,Fs); % check tapers 0052 J1=mtfftc(data1,tapers,nfft,Fs); 0053 J2=mtfftc(data2,tapers,nfft,Fs); 0054 J1=J1(findx,:,:); J2=J2(findx,:,:); 0055 S12=squeeze(mean(conj(J1).*J2,2)); 0056 S1=squeeze(mean(conj(J1).*J1,2)); 0057 S2=squeeze(mean(conj(J2).*J2,2)); 0058 if trialave; S12=squeeze(mean(S12,2)); S1=squeeze(mean(S1,2)); S2=squeeze(mean(S2,2)); end; 0059 C12=S12./sqrt(S1.*S2); 0060 %if trialave; C12=squeeze(mean(C12,2)); end; 0061 C=abs(C12); 0062 phi=angle(C12); 0063 if nargout==6; 0064 [confC,phierr,Cerr]=coherr(C,J1,J2,err,trialave); 0065 elseif nargout==5; 0066 [confC,phierr]=coherr(C,J1,J2,err,trialave); 0067 end;