mtspectrumpt

PURPOSE ^

Multi-taper spectrum - point process times

SYNOPSIS ^

function [S,f,R,Serr]=mtspectrumpt(data,tapers,pad,Fs,fpass,err,trialave,fscorr,t)

DESCRIPTION ^

 Multi-taper spectrum - point process times

 Usage:

 [S,f,R,Serr]=mtspectrumpt(data,tapers,pad,Fs,fpass,err,trialave,fscorr)
 Input: 
       data        (structure array of channels/trials with spike times) -- required
       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          (binning frequency for fft grid used to calculate fft of prolates. 1/Fs is the time between consecutive
                                   points on the grid used for evaluation of the prolates) - 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 when 1, don't average when 0) - optional. Default 0
       fscorr   (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
                (available only for spikes). Defaults 0.
       t        (time grid over which the tapers are to be calculated:
                      this argument is useful when calling the spectrum
                      calculation routine from a moving window spectrogram
                      calculation routine). If left empty, the spike times
                      are used to define the grid.
 Output:
       S       (spectrum in form frequency x channels/trials)
       f       (frequencies)
       R       (rate)
       Serr    (error bars)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [S,f,R,Serr]=mtspectrumpt(data,tapers,pad,Fs,fpass,err,trialave,fscorr,t)
0002 % Multi-taper spectrum - point process times
0003 %
0004 % Usage:
0005 %
0006 % [S,f,R,Serr]=mtspectrumpt(data,tapers,pad,Fs,fpass,err,trialave,fscorr)
0007 % Input:
0008 %       data        (structure array of channels/trials with spike times) -- required
0009 %       tapers      (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not
0010 %                                                 specified, use [NW K]=[3 5]
0011 %        pad            (padding factor for the FFT) - optional. Defaults to 0.
0012 %                       e.g. For N = 500, if PAD = 0, we pad the FFT
0013 %                       to 512 points; if PAD = 2, we pad the FFT
0014 %                       to 2048 points, etc.
0015 %       Fs          (binning frequency for fft grid used to calculate fft of prolates. 1/Fs is the time between consecutive
0016 %                                   points on the grid used for evaluation of the prolates) - optional. Default 1.
0017 %       fpass       (frequency band to be used in the calculation in the form
0018 %                                   [fmin fmax])- optional.
0019 %                                   Default all frequencies between 0 and Fs/2
0020 %       err         (error calculation [1 p] - Theoretical error bars; [2 p] Jackknife error bars
0021 %                                   [0 p] or 0 - no error bars) - optional. Default 0.
0022 %       trialave (average over trials when 1, don't average when 0) - optional. Default 0
0023 %       fscorr   (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
0024 %                (available only for spikes). Defaults 0.
0025 %       t        (time grid over which the tapers are to be calculated:
0026 %                      this argument is useful when calling the spectrum
0027 %                      calculation routine from a moving window spectrogram
0028 %                      calculation routine). If left empty, the spike times
0029 %                      are used to define the grid.
0030 % Output:
0031 %       S       (spectrum in form frequency x channels/trials)
0032 %       f       (frequencies)
0033 %       R       (rate)
0034 %       Serr    (error bars)
0035 if nargin < 1; error('Need data'); end;
0036 if nargin < 2; tapers=[3 5];end;
0037 if nargin < 3; pad=0;end;
0038 if nargin < 4; Fs=1; end;
0039 if nargin < 5; fpass=[0 Fs/2]; end;
0040 if nargin < 6; err=0; end;
0041 if nargin < 7; trialave=0; end;
0042 if nargin < 8; fscorr=0;end;
0043 if nargin < 9;
0044    [mintime,maxtime]=minmaxsptimes(data);
0045    dt=1/Fs; % sampling time
0046    t=mintime-dt:dt:maxtime+dt; % time grid for prolates
0047 end;
0048 N=length(t); % number of points in grid for dpss
0049 if isempty(tapers); tapers=[3 5]; end;
0050 if isempty(pad);pad=0;end;
0051 if isempty(Fs); Fs=1; end;
0052 if isempty(fpass); fpass=[0 Fs/2]; end;
0053 if isempty(err); err=0; end;
0054 if isempty(trialave); trialave=0;end;
0055 if isempty(fscorr);fscorr=0;end
0056 
0057 nfft=2^(nextpow2(N)+pad); % number of points in fft of prolates
0058 [f,findx]=getfgrid(Fs,nfft,fpass); % get frequency grid for evaluation
0059 tapers=dpsschk(tapers,N)*sqrt(Fs); % check tapers
0060 [J,Msp,Nsp]=mtfftpt(data,tapers,nfft,t,f,findx); % mt fft for point process times
0061 S=squeeze(mean(conj(J).*J,2));
0062 if trialave; S=squeeze(mean(S,2));Msp=mean(Msp);end;
0063 R=Msp*Fs;
0064 if nargout==4;
0065    if fscorr==1;
0066       Serr=specerr(S,J,err,trialave,Nsp);
0067    else;
0068       Serr=specerr(S,J,err,trialave);
0069    end;
0070 end;

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