function [P,Fstat,f0]=mtpowerandfstatc(data,params,f0) % Multi-taper computation of the power and the fstatistic for a particular frequency - continuous process % % Usage: % % [P,Fstat,f0]=mtpowerandfstatc(data,params,f0) % Input: % Note units have to be consistent. See chronux.m for more information. % data (in form samples x channels/trials or a single vector) -- required % params: structure with fields tapers, pad, Fs, fpass, err, trialave % -optional % tapers : precalculated tapers from dpss or in the one of the following % forms: % (1) A numeric vector [TW K] where TW is the % time-bandwidth product and K is the number of % tapers to be used (less than or equal to % 2TW-1). % (2) A numeric vector [W T p] where W is the % bandwidth, T is the duration of the data and p % is an integer such that 2TW-p tapers are used. In % this form there is no default i.e. to specify % the bandwidth, you have to specify T and p as % well. Note that the units of W and T have to be % consistent: if W is in Hz, T must be in seconds % and vice versa. Note that these units must also % be consistent with the units of params.Fs: W can % be in Hz if and only if params.Fs is in Hz. % The default is to use form 1 with TW=3 and K=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. % f0 (frequency of calculation) % Output: % P (integrated power within the frequency range of interest (trapezoidal integration)) % Fstat (F-statistic) % f0 (frequency) if nargin < 1; error('Need data'); end; if nargin < 2; params=[]; end; [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); clear fpass err trialave params data=change_row_to_column(data); [N,C]=size(data); tapers=dpsschk(tapers,N,Fs); % calculate the tapers [N,K]=size(tapers); nfft=max(2^(nextpow2(N)+pad),N);% number of points in fft %[f0,findx]=getfgrid(Fs,nfft,f0);% frequency grid to be returned tapers=tapers(:,:,ones(1,C)); % add channel indices to tapers data=data(:,:,ones(1,K)); % add taper indices to data data=permute(data,[1 3 2]); % reshape data to get dimensions to match those of tapers data_proj=data.*tapers; % product of data with tapers in the form time x tapers x channels t=(0:N-1)'/Fs; fourier=exp(-i*2*pi*f0*t); fourier=fourier(:,ones(1,K),ones(1,C)); J=squeeze(sum(fourier.*data_proj))/Fs; Kodd=1:2:K; Keven=2:2:K; tapers=tapers(:,:,ones(1,C)); % add channel indices to the tapers - t x K x C H0 = squeeze(sum(tapers(:,Kodd,:),1)); % calculate sum of tapers for even prolates - K x C if C==1; H0=H0'; J=J'; end; P=squeeze(mean(J.*conj(J),1)); Jp=J(Kodd,:); % drop the even ffts H0sq=sum(H0.*H0,1);% sum of squares of H0^2 across taper indices - dimensions C JpH0=sum(Jp.*H0,1);% sum of the product of Jp and H0 across taper indices - f x C\ A=squeeze(JpH0./H0sq); % amplitudes for all frequencies and channels Kp=size(Jp,1); % number of even prolates Ap=A(ones(1,Kp),:); % add the taper index to C Jhat=Ap.*H0; % fitted value for the fft num=(K-1).*(abs(A).^2).*squeeze(H0sq);%numerator for F-statistic den=squeeze(sum(abs(Jp-Jhat).^2,1)+sum(abs(J(Keven,:)).^2,1));% denominator for F-statistic Fstat=num./den; % F-statisitic