


Multi-taper time-frequency spectrum - continuous process
Usage:
[S,t,f,Serr]=mtspecgramc(data,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.
data (in form samples x channels/trials) -- required
movingwin (in the form [window winstep] i.e length of moving
window and step size)
Note that units here have
to be consistent with
units of Fs - 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/channels when 1, don't average when 0) - optional. Default 0
Output:
S (spectrum in form time x frequency x channels/trials if trialave=0; in the form time x frequency if trialave=1)
t (times)
f (frequencies)
Serr (error bars) only for err(1)>=1

0001 function [S,t,f,Serr]=mtspecgramc(data,movingwin,params) 0002 % Multi-taper time-frequency spectrum - continuous process 0003 % 0004 % Usage: 0005 % [S,t,f,Serr]=mtspecgramc(data,movingwin,params) 0006 % Input: 0007 % Note units have to be consistent. Thus, if movingwin is in seconds, Fs 0008 % has to be in Hz. see chronux.m for more information. 0009 % data (in form samples x channels/trials) -- required 0010 % movingwin (in the form [window winstep] i.e length of moving 0011 % window and step size) 0012 % Note that units here have 0013 % to be consistent with 0014 % units of Fs - required 0015 % params: structure with fields tapers, pad, Fs, fpass, err, trialave 0016 % - optional 0017 % tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 0018 % specified, use [NW K]=[3 5] 0019 % pad (padding factor for the FFT) - optional. Defaults to 0. 0020 % e.g. For N = 500, if PAD = 0, we pad the FFT 0021 % to 512 points; if PAD = 2, we pad the FFT 0022 % to 2048 points, etc. 0023 % Fs (sampling frequency) - optional. Default 1. 0024 % fpass (frequency band to be used in the calculation in the form 0025 % [fmin fmax])- optional. 0026 % Default all frequencies between 0 and Fs/2 0027 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0028 % [0 p] or 0 - no error bars) - optional. Default 0. 0029 % trialave (average over trials/channels when 1, don't average when 0) - optional. Default 0 0030 % Output: 0031 % S (spectrum in form time x frequency x channels/trials if trialave=0; in the form time x frequency if trialave=1) 0032 % t (times) 0033 % f (frequencies) 0034 % Serr (error bars) only for err(1)>=1 0035 0036 if nargin < 2; error('Need data and window parameters'); end; 0037 if nargin < 3; params=[]; end; 0038 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0039 if nargout > 3 && err(1)==0; 0040 % Cannot compute error bars with err(1)=0. change params and run again. 0041 error('When Serr is desired, err(1) has to be non-zero.'); 0042 end; 0043 data=change_row_to_column(data); 0044 [N,Ch]=size(data); 0045 Nwin=round(Fs*movingwin(1)); % number of samples in window 0046 Nstep=round(movingwin(2)*Fs); % number of samples to step through 0047 nfft=2^(nextpow2(Nwin)+pad); 0048 f=getfgrid(Fs,nfft,fpass); Nf=length(f); 0049 params.tapers=dpsschk(tapers,Nwin,Fs); % check tapers 0050 0051 winstart=1:Nstep:N-Nwin+1; 0052 nw=length(winstart); 0053 0054 if trialave 0055 S = zeros(nw,Nf); 0056 if nargout==4; Serr=zeros(2,nw,Nf); end; 0057 else 0058 S = zeros(nw,Nf,Ch); 0059 if nargout==4; Serr=zeros(2,nw,Nf,Ch); end; 0060 end 0061 0062 for n=1:nw; 0063 indx=winstart(n):winstart(n)+Nwin-1; 0064 datawin=data(indx,:); 0065 if nargout==4 0066 [s,f,serr]=mtspectrumc(datawin,params); 0067 Serr(1,n,:,:)=squeeze(serr(1,:,:)); 0068 Serr(2,n,:,:)=squeeze(serr(2,:,:)); 0069 else 0070 [s,f]=mtspectrumc(datawin,params); 0071 end 0072 S(n,:,:)=s; 0073 end; 0074 S=squeeze(S); 0075 if nargout==4;Serr=squeeze(Serr);end; 0076 winmid=winstart+round(Nwin/2); 0077 t=winmid/Fs;