% Multi-taper spectrum - continuous process
% 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
% tapers : precalculated tapers from dpss or in the one of the following
% (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
% (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
% 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)>=1
if nargin < 1; error('Need data'); end;
if nargin < 2; params=; end;
if nargout > 2 && err(1)==0;
% Cannot compute error bars with err(1)=0. Change params and run again.
error('When Serr is desired, err(1) has to be non-zero.');
tapers=dpsschk(tapers,N,Fs); % check tapers
if trialave; S=squeeze(mean(S,2));end;