


Multi-taper coherency,cross-spectral matrix - continuous process
Usage:
[C,phi,S12,f,confC,phistd,Cerr]=cohmatrixc(data,params)
Input:
Note units have to be consistent. See chronux.m for more information.
data (in form samples x channels) -- required
params: structure with fields tapers, pad, Fs, fpass, err
- 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.
Output:
C (magnitude of coherency frequency x channels x channels)
phi (phase of coherency frequency x channels x channels)
S12 (cross-spectral matrix frequency x channels x channels)
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)

0001 function [C,phi,S12,f,confC,phistd,Cerr]=cohmatrixc(data,params) 0002 % Multi-taper coherency,cross-spectral matrix - continuous process 0003 % 0004 % Usage: 0005 % 0006 % [C,phi,S12,f,confC,phistd,Cerr]=cohmatrixc(data,params) 0007 % Input: 0008 % Note units have to be consistent. See chronux.m for more information. 0009 % data (in form samples x channels) -- required 0010 % params: structure with fields tapers, pad, Fs, fpass, err 0011 % - optional 0012 % tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 0013 % specified, use [NW K]=[3 5] 0014 % pad (padding factor for the FFT) - optional (can take values -1,0,1,2...). 0015 % -1 corresponds to no padding, 0 corresponds to padding 0016 % to the next highest power of 2 etc. 0017 % e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT 0018 % to 512 points, if pad=1, we pad to 1024 points etc. 0019 % Defaults to 0. 0020 % Fs (sampling frequency) - optional. Default 1. 0021 % fpass (frequency band to be used in the calculation in the form 0022 % [fmin fmax])- optional. 0023 % Default all frequencies between 0 and Fs/2 0024 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0025 % [0 p] or 0 - no error bars) - optional. Default 0. 0026 % Output: 0027 % C (magnitude of coherency frequency x channels x channels) 0028 % phi (phase of coherency frequency x channels x channels) 0029 % S12 (cross-spectral matrix frequency x channels x channels) 0030 % f (frequencies) 0031 % confC (confidence level for C at 1-p %) - only for err(1)>=1 0032 % phistd - theoretical/jackknife (depending on err(1)=1/err(1)=2) standard deviation for phi - Note that 0033 % phi + 2 phistd and phi - 2 phistd will give 95% confidence 0034 % bands for phi - only for err(1)>=1 0035 % Cerr (Jackknife error bars for C - use only for Jackknife - err(1)=2) 0036 if nargin < 1; error('need data'); end; 0037 if nargin < 2; params=[]; end; 0038 [N,Ch]=size(data); 0039 if Ch==1; error('Need at least two channels of data'); end; 0040 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0041 clear trialave params 0042 if nargout > 6 && err(1)~=2; 0043 error('Cerr computed only for Jackknife. Correct inputs and run again'); 0044 end; 0045 if nargout >= 4 && err(1)==0; 0046 % Errors computed only if err(1) is nonzero. Need to change params and run again. 0047 error('When errors are desired, err(1) has to be non-zero.'); 0048 end; 0049 nfft=max(2^(nextpow2(N)+pad),N); 0050 [f,findx]=getfgrid(Fs,nfft,fpass); 0051 tapers=dpsschk(tapers,N,Fs); % check tapers 0052 J=mtfftc(data,tapers,nfft,Fs); 0053 J=J(findx,:,:); 0054 if err(1)==0; 0055 [C,phi,S12]=cohmathelper(J,err); 0056 elseif err(1)==1; 0057 [C,phi,S12,confC,phistd]=cohmathelper(J,err); 0058 elseif err(1)==2; 0059 [C,phi,S12,confC,phistd,Cerr]=cohmathelper(J,err); 0060 end