


Multi-taper segmented spectrum for a univariate binned point process
Usage:
[S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpb(data,win,params,segave,fscorr)
Input:
Note units have to be consistent. See chronux.m for more information.
data (in form samples x 1) -- required
win (duration of the segments) - 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. 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.
segave (1 for averaging across segments, 0 otherwise; default 1)
fscorr (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
(available only for spikes). Defaults 0.
Output:
S (spectrum in form frequency x segments if segave=0; as a function of frequency if segave=1)
f (frequencies)
R (spike rate)
varS (variance of the log spectrum)
zerosp (0 for segments in which spikes were found, 1 for segments
in which there are no spikes)
C (covariance matrix of the log spectrum - frequency x
frequency matrix)
Serr (error bars) - only for err(1)>=1

0001 function [S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpb(data,win,params,segave,fscorr) 0002 % Multi-taper segmented spectrum for a univariate binned point process 0003 % 0004 % Usage: 0005 % 0006 % [S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpb(data,win,params,segave,fscorr) 0007 % Input: 0008 % Note units have to be consistent. See chronux.m for more information. 0009 % data (in form samples x 1) -- required 0010 % win (duration of the segments) - required. 0011 % params: structure with fields tapers, pad, Fs, fpass, err 0012 % - optional 0013 % tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 0014 % specified, use [NW K]=[3 5] 0015 % pad (padding factor for the FFT) - optional. Defaults to 0. 0016 % e.g. For N = 500, if PAD = 0, we pad the FFT 0017 % to 512 points; if PAD = 2, we pad the FFT 0018 % to 2048 points, etc. 0019 % Fs (sampling frequency) - optional. Default 1. 0020 % fpass (frequency band to be used in the calculation in the form 0021 % [fmin fmax])- optional. 0022 % Default all frequencies between 0 and Fs/2 0023 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0024 % [0 p] or 0 - no error bars) - optional. Default 0. 0025 % segave (1 for averaging across segments, 0 otherwise; default 1) 0026 % fscorr (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional 0027 % (available only for spikes). Defaults 0. 0028 % Output: 0029 % S (spectrum in form frequency x segments if segave=0; as a function of frequency if segave=1) 0030 % f (frequencies) 0031 % R (spike rate) 0032 % varS (variance of the log spectrum) 0033 % zerosp (0 for segments in which spikes were found, 1 for segments 0034 % in which there are no spikes) 0035 % C (covariance matrix of the log spectrum - frequency x 0036 % frequency matrix) 0037 % Serr (error bars) - only for err(1)>=1 0038 0039 0040 if nargin < 2; error('Need data and segment information'); end; 0041 if nargin < 3; params=[]; end; 0042 if nargin < 4 || isempty(segave); segave=1; end; 0043 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0044 if nargin < 3 || isempty(fscorr); fscorr=0;end; 0045 0046 if nargout > 4 && err(1)==0; 0047 % Cannot compute error bars with err(1)=0. Need to change params and run again. 0048 error('When Serr is desired, err(1) has to be non-zero.'); 0049 end; 0050 0051 N=size(data,1); % total length of data 0052 dt=1/Fs; % sampling interval 0053 T=N*dt; % length of data in seconds 0054 E=0:win:T-win; % fictitious event triggers 0055 win=[0 win]; % use window length to define left and right limits of windows around triggers 0056 data=createdatamatpb(data,E,Fs,win); 0057 zerosp=zeros(1,size(data,2)); 0058 N=size(data,1); % length of segmented data 0059 nfft=2^(nextpow2(N)+pad); 0060 [f,findx]=getfgrid(Fs,nfft,fpass); 0061 tapers=dpsschk(tapers,N,Fs); % check tapers 0062 [J,Msp,Nsp]=mtfftpb(data,tapers,nfft); 0063 zerosp(find(Nsp==0))=1; 0064 J=J(findx,:,:); 0065 R=Msp*Fs; 0066 S=squeeze(mean(conj(J).*J,2)); % spectra of non-overlapping segments (averaged over tapers) 0067 lS=log(S); % log spectrum 0068 C=cov(lS')'; % covariance of the log spectrum - frequency x frequency 0069 varS=diag(C); % variance of the log spectrum 0070 if segave; 0071 S=squeeze(mean(S,2)); % mean of the spectrum averaged across segments 0072 R=squeeze(mean(R)); % mean of the spike rate averaged across segments 0073 end 0074 if nargout==6; 0075 if fscorr==1; 0076 Serr=specerr(S,J,err,trialave,Nsp); 0077 else 0078 Serr=specerr(S,J,err,trialave); 0079 end; 0080 end;