


Multi-taper spectral derivative - binned point process
Usage:
[dS,f]=mtdspectrumpb(data,phi,params)
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 (in form samples x channels/trials) -- 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) -- required.
e.g. phi=[0,pi/2] giving the time and frequency
derivatives
params: structure with fields tapers, pad, Fs, fpass, trialave
-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
trialave (average over trials when 1, don't average when 0) -
optional. Default 0
Output:
dS (derivative of the spectrum in form phi x frequency x channels/trials if trialave=0; in the form phi x frequency if trialave=1)
f (frequencies)

0001 function [dS,f]=mtdspectrumpb(data,phi,params) 0002 % Multi-taper spectral derivative - binned point process 0003 % 0004 % Usage: 0005 % 0006 % [dS,f]=mtdspectrumpb(data,phi,params) 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 (in form samples x channels/trials) -- 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) -- required. 0016 % e.g. phi=[0,pi/2] giving the time and frequency 0017 % derivatives 0018 % params: structure with fields tapers, pad, Fs, fpass, trialave 0019 % -optional 0020 % tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 0021 % specified, use [NW K]=[3 5] 0022 % pad (padding factor for the FFT) - optional. Defaults to 0. 0023 % e.g. For N = 500, if PAD = 0, we pad the FFT 0024 % to 512 points; if PAD = 2, we pad the FFT 0025 % to 2048 points, etc. 0026 % Fs (sampling frequency) - optional. Default 1. 0027 % fpass (frequency band to be used in the calculation in the form 0028 % [fmin fmax])- optional. 0029 % Default all frequencies between 0 and 0030 % Fs/2 0031 % trialave (average over trials when 1, don't average when 0) - 0032 % optional. Default 0 0033 % Output: 0034 % dS (derivative of the spectrum in form phi x frequency x channels/trials if trialave=0; in the form phi x frequency if trialave=1) 0035 % f (frequencies) 0036 0037 if nargin < 2; error('Need data and angle'); end; 0038 if nargin < 3; params=[]; end; 0039 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0040 0041 N=size(data,1); 0042 nfft=2^(nextpow2(N)+pad); 0043 [f,findx]=getfgrid(Fs,nfft,fpass); 0044 tapers=dpsschk(tapers,N,Fs); % check tapers 0045 K=size(tapers,2); 0046 [J,Msp,Nsp]=mtfftpb(data,tapers,nfft); 0047 J=J(findx,:,:); 0048 S=squeeze(mean(J(:,1:K-1,:).*conj(J(:,2:K,:)),2)); 0049 if trialave; S=squeeze(mean(S,2)); end; 0050 nphi=length(phi); 0051 for p=1:nphi; 0052 dS(p,:,:)=real(exp(i*phi(p))*S); 0053 end; 0054 dS=squeeze(dS);