Multi-taper spectrum - continuous process
Usage:
[S,f,Serr]=mtspectrumc(data,params)
Input:
Note units have to be consistent. See chronux.m for more information.
data (in form samples x channels/trials) -- 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.
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 frequency x channels/trials if trialave=0;
in the form frequency if trialave=1)
f (frequencies)
Serr (error bars) only for err(1)>=10001 function [S,f,Serr]=mtspectrumc(data,params) 0002 % Multi-taper spectrum - continuous process 0003 % 0004 % Usage: 0005 % 0006 % [S,f,Serr]=mtspectrumc(data,params) 0007 % Input: 0008 % Note units have to be consistent. See chronux.m for more information. 0009 % data (in form samples x channels/trials) -- required 0010 % params: structure with fields tapers, pad, Fs, fpass, err, trialave 0011 % -optional 0012 % tapers : precalculated tapers from dpss or in the one of the following 0013 % forms: 0014 % (1) A numeric vector [TW K] where TW is the 0015 % time-bandwidth product and K is the number of 0016 % tapers to be used (less than or equal to 0017 % 2TW-1). 0018 % (2) A numeric vector [W T p] where W is the 0019 % bandwidth, T is the duration of the data and p 0020 % is an integer such that 2TW-p tapers are used. In 0021 % this form there is no default i.e. to specify 0022 % the bandwidth, you have to specify T and p as 0023 % well. Note that the units of W and T have to be 0024 % consistent: if W is in Hz, T must be in seconds 0025 % and vice versa. Note that these units must also 0026 % be consistent with the units of params.Fs: W can 0027 % be in Hz if and only if params.Fs is in Hz. 0028 % The default is to use form 1 with TW=3 and K=5 0029 % 0030 % pad (padding factor for the FFT) - optional (can take values -1,0,1,2...). 0031 % -1 corresponds to no padding, 0 corresponds to padding 0032 % to the next highest power of 2 etc. 0033 % e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT 0034 % to 512 points, if pad=1, we pad to 1024 points etc. 0035 % Defaults to 0. 0036 % Fs (sampling frequency) - optional. Default 1. 0037 % fpass (frequency band to be used in the calculation in the form 0038 % [fmin fmax])- optional. 0039 % Default all frequencies between 0 and Fs/2 0040 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0041 % [0 p] or 0 - no error bars) - optional. Default 0. 0042 % trialave (average over trials/channels when 1, don't average when 0) - optional. Default 0 0043 % Output: 0044 % S (spectrum in form frequency x channels/trials if trialave=0; 0045 % in the form frequency if trialave=1) 0046 % f (frequencies) 0047 % Serr (error bars) only for err(1)>=1 0048 0049 if nargin < 1; error('Need data'); end; 0050 if nargin < 2; params=[]; end; 0051 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0052 if nargout > 2 && err(1)==0; 0053 % Cannot compute error bars with err(1)=0. Change params and run again. 0054 error('When Serr is desired, err(1) has to be non-zero.'); 0055 end; 0056 data=change_row_to_column(data); 0057 N=size(data,1); 0058 nfft=max(2^(nextpow2(N)+pad),N); 0059 [f,findx]=getfgrid(Fs,nfft,fpass); 0060 tapers=dpsschk(tapers,N,Fs); % check tapers 0061 J=mtfftc(data,tapers,nfft,Fs); 0062 J=J(findx,:,:); 0063 S=squeeze(mean(conj(J).*J,2)); 0064 if trialave; S=squeeze(mean(S,2));end; 0065 if nargout==3; 0066 Serr=specerr(S,J,err,trialave); 0067 end;