Home > chronux > spectral_analysis > pointbinned > mtdspectrumpb.m

# mtdspectrumpb

## PURPOSE Multi-taper spectral derivative - binned point process

## SYNOPSIS function [dS,f]=mtdspectrumpb(data,phi,params)

## DESCRIPTION ``` 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 or single vector) -- 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 one of the following
forms:
(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
2TW-1).
(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
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)```

## CROSS-REFERENCE INFORMATION This function calls:
• mtfftpb Multi-taper fourier transform - binned point process data
This function is called by:
• mtdspecgrampb Multi-taper derivatives of time-frequency spectrum - binned point process

## SOURCE CODE ```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 or single vector) -- required
0013 %       tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional.
0014 %                                                 If not 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 one of the following
0021 %                    forms:
0022 %                   (1) A numeric vector [TW K] where TW is the
0023 %                       time-bandwidth product and K is the number of
0024 %                       tapers to be used (less than or equal to
0025 %                       2TW-1).
0026 %                   (2) A numeric vector [W T p] where W is the
0027 %                       bandwidth, T is the duration of the data and p
0028 %                       is an integer such that 2TW-p tapers are used. In
0029 %                       this form there is no default i.e. to specify
0030 %                       the bandwidth, you have to specify T and p as
0031 %                       well. Note that the units of W and T have to be
0032 %                       consistent: if W is in Hz, T must be in seconds
0033 %                       and vice versa. Note that these units must also
0034 %                       be consistent with the units of params.Fs: W can
0035 %                       be in Hz if and only if params.Fs is in Hz.
0036 %                       The default is to use form 1 with TW=3 and K=5
0037 %
0038 %            pad            (padding factor for the FFT) - optional (can take values -1,0,1,2...).
0039 %                    -1 corresponds to no padding, 0 corresponds to padding
0040 %                    to the next highest power of 2 etc.
0041 %                       e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
0042 %                       to 512 points, if pad=1, we pad to 1024 points etc.
0043 %                       Defaults to 0.
0044 %           Fs   (sampling frequency) - optional. Default 1.
0045 %           fpass    (frequency band to be used in the calculation in the form
0046 %                                   [fmin fmax])- optional.
0047 %                                   Default all frequencies between 0 and
0048 %                                   Fs/2
0049 %           trialave (average over trials when 1, don't average when 0) -
0050 %           optional. Default 0
0051 % Output:
0052 %       dS       (derivative of the spectrum in form phi x frequency x channels/trials if trialave=0;
0053 %                in the form phi x frequency if trialave=1)
0054 %       f        (frequencies)
0055
0056 if nargin < 2; error('Need data and angle'); end;
0057 if nargin < 3; params=[]; end;
0059 clear err params
0060 data=change_row_to_column(data);
0061 N=size(data,1);
0063 [f,findx]=getfgrid(Fs,nfft,fpass);
0064 tapers=dpsschk(tapers,N,Fs); % check tapers
0065 K=size(tapers,2);
0066 J=mtfftpb(data,tapers,nfft);
0067 J=J(findx,:,:);
0068 A=sqrt(1:K-1);
0069 A=repmat(A,[size(J,1) 1]);
0070 A=repmat(A,[1 1 size(J,3)]);
0071 % S=squeeze(mean(J(:,1:K-1,:).*conj(J(:,2:K,:)),2));
0072 S=squeeze(mean(J(:,1:K-1,:).*A.*conj(J(:,2:K,:)),2));
0073 if trialave; S=squeeze(mean(S,2)); end;
0074 nphi=length(phi);
0075 for p=1:nphi;
0076     dS(p,:,:)=real(exp(i*phi(p))*S);
0077 end;
0078 dS=squeeze(dS);
0079 dS=change_row_to_column(dS);```

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