


Multi-taper spectral derivative - point process times
Usage:
[dS,f]=mtdspectrumpt(data,tapers,phi,pad,Fs,fpass,trialave,t)
Input:
Note that all times can be in arbitrary units. But the units have to be
consistent. So, if E is in secs, win, t have to be in secs, and Fs has to
be Hz. If E is in samples, so are win and t, and Fs=1. In case of spike
times, the units have to be consistent with the units of data as well.
data (structure array of spike times with dimension channels/trials; also accepts 1d array of 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]
phi (angle for evaluation of derivative) -- optional.
Default phi=[0,pi/2] giving the time and frequency derivatives
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
trialave (average over trials when 1, don't average when 0) -
optional. Default 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:
dS (spectrum in form angle x frequency x taper index x channels/trials)
f (frequencies)

0001 function [dS,f]=mtdspectrumpt(data,tapers,phi,pad,Fs,fpass,trialave,t) 0002 % Multi-taper spectral derivative - point process times 0003 % 0004 % Usage: 0005 % 0006 % [dS,f]=mtdspectrumpt(data,tapers,phi,pad,Fs,fpass,trialave,t) 0007 % Input: 0008 % Note that all times can be in arbitrary units. But the units have to be 0009 % consistent. So, if E is in secs, win, t have to be in secs, and Fs has to 0010 % be Hz. If E is in samples, so are win and t, and Fs=1. In case of spike 0011 % times, the units have to be consistent with the units of data as well. 0012 % data (structure array of spike times with dimension channels/trials; also accepts 1d array of spike times) -- required 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 % phi (angle for evaluation of derivative) -- optional. 0016 % Default phi=[0,pi/2] giving the time and frequency derivatives 0017 % pad (padding factor for the FFT) - optional. Defaults to 0. 0018 % e.g. For N = 500, if PAD = 0, we pad the FFT 0019 % to 512 points; if PAD = 2, we pad the FFT 0020 % to 2048 points, etc. 0021 % Fs (binning frequency for fft grid used to calculate fft of prolates. 1/Fs is the time between consecutive 0022 % points on the grid used for evaluation of the prolates) - optional. Default 1. 0023 % fpass (frequency band to be used in the calculation in the form 0024 % [fmin fmax])- optional. 0025 % Default all frequencies between 0 and Fs/2 0026 % trialave (average over trials when 1, don't average when 0) - 0027 % optional. Default 0 0028 % t (time grid over which the tapers are to be calculated: 0029 % this argument is useful when calling the spectrum 0030 % calculation routine from a moving window spectrogram 0031 % calculation routine). If left empty, the spike times 0032 % are used to define the grid. 0033 % Output: 0034 % dS (spectrum in form angle x frequency x taper index x channels/trials) 0035 % f (frequencies) 0036 if nargin < 1; error('Need data'); end; 0037 if nargin < 2; tapers=[3 5]; end; 0038 if nargin < 3; phi=[0 pi/2];end; 0039 if nargin < 4;pad=0;end; 0040 if nargin < 5; Fs=1; end; 0041 if nargin < 6; fpass=[0 Fs/2]; end; 0042 if nargin < 7; trialave=0; end; 0043 dt=1/Fs; % sampling time 0044 if nargin < 8; 0045 [mintime,maxtime]=minmaxsptimes(data); 0046 t=mintime:dt:maxtime+dt; % time grid for prolates 0047 end; 0048 N=length(t); % number of points in grid for dpss 0049 nfft=2^(nextpow2(N)+pad); % number of points in fft of prolates 0050 [f,findx]=getfgrid(Fs,nfft,fpass); % get frequency grid for evaluation 0051 tapers=dpsschk(tapers,N,Fs); % check tapers 0052 K=size(tapers,2); 0053 [J,Msp,Nsp]=mtfftpt(data,tapers,nfft,Fs,t,f,findx); % mt fft for point process times 0054 S=squeeze(mean(J(:,1:K-1,:).*conj(J(:,2:K,:)),2)); 0055 if trialave; S=squeeze(mean(S,2));end; 0056 nphi=length(phi); 0057 for p=1:nphi; 0058 dS(p,:,:)=real(exp(i*phi(p))*S); 0059 end; 0060 dS=squeeze(dS);