Home > chronux > spectral_analysis > pointtimes > mtdspecgrampt.m

# mtdspecgrampt

## PURPOSE

Multi-taper derivative time-frequency spectrum - point process times

## SYNOPSIS

function [dS,t,f]=mtdspecgrampt(data,movingwin,phi,params)

## DESCRIPTION

``` Multi-taper derivative time-frequency spectrum - point process times

Usage:

[dS,t,f]=mtdspecgrampt(data,movingwin,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        (structure array of spike times with dimension channels/trials;
also accepts 1d array of spike times) -- required
movingwin         (in the form [window winstep] i.e length of moving
window and step size.
Note that units here have
to be consistent with
units of Fs
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
Note that T has to be equal to movingwin(1).

pad            (padding factor for the FFT) - optional (can take values -1,0,1,2...).
to the next highest power of 2 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      (spectral derivative in form phi x time x frequency x channels/trials if trialave=0;
in form phi x time x frequency if trialave=1)
t       (times)
f       (frequencies)```

## CROSS-REFERENCE INFORMATION

This function calls:
• extractdatapt Extract segements of spike times between t(1) and t(2)
• minmaxsptimes Find the minimum and maximum of the spike times in each channel
• mtdspectrumpt Multi-taper spectral derivative - point process times
This function is called by:

## SOURCE CODE

```0001 function [dS,t,f]=mtdspecgrampt(data,movingwin,phi,params)
0002 % Multi-taper derivative time-frequency spectrum - point process times
0003 %
0004 % Usage:
0005 %
0006 % [dS,t,f]=mtdspecgrampt(data,movingwin,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        (structure array of spike times with dimension channels/trials;
0013 %                   also accepts 1d array of spike times) -- required
0014 %       movingwin         (in the form [window winstep] i.e length of moving
0015 %                                                 window and step size.
0016 %                                                 Note that units here have
0017 %                                                 to be consistent with
0018 %                                                 units of Fs
0019 %       phi         (angle for evaluation of derivative) -- required.
0020 %                       e.g. phi=[0,pi/2] giving the time and frequency
0021 %                       derivatives
0022 %       params: structure with fields tapers, pad, Fs, fpass, trialave
0023 %       -optional
0024 %           tapers : precalculated tapers from dpss or in the one of the following
0025 %                    forms:
0026 %                   (1) A numeric vector [TW K] where TW is the
0027 %                       time-bandwidth product and K is the number of
0028 %                       tapers to be used (less than or equal to
0029 %                       2TW-1).
0030 %                   (2) A numeric vector [W T p] where W is the
0031 %                       bandwidth, T is the duration of the data and p
0032 %                       is an integer such that 2TW-p tapers are used. In
0033 %                       this form there is no default i.e. to specify
0034 %                       the bandwidth, you have to specify T and p as
0035 %                       well. Note that the units of W and T have to be
0036 %                       consistent: if W is in Hz, T must be in seconds
0037 %                       and vice versa. Note that these units must also
0038 %                       be consistent with the units of params.Fs: W can
0039 %                       be in Hz if and only if params.Fs is in Hz.
0040 %                       The default is to use form 1 with TW=3 and K=5
0041 %                   Note that T has to be equal to movingwin(1).
0042 %
0043 %            pad            (padding factor for the FFT) - optional (can take values -1,0,1,2...).
0045 %                    to the next highest power of 2 etc.
0046 %                       e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
0047 %                       to 512 points, if pad=1, we pad to 1024 points etc.
0048 %                       Defaults to 0.
0049 %           Fs   (sampling frequency) - optional. Default 1.
0050 %           fpass    (frequency band to be used in the calculation in the form
0051 %                                   [fmin fmax])- optional.
0052 %                                   Default all frequencies between 0 and
0053 %                                   Fs/2
0054 %           trialave (average over trials when 1, don't average when 0) -
0055 %           optional. Default 0
0056 % Output:
0057 %       dS      (spectral derivative in form phi x time x frequency x channels/trials if trialave=0;
0058 %               in form phi x time x frequency if trialave=1)
0059 %       t       (times)
0060 %       f       (frequencies)
0061
0062 if nargin < 3; error('Need data, window parameters and angle'); end;
0063 if nargin < 4; params=[]; end;
0064
0065 if length(params.tapers)==3 & movingwin(1)~=params.tapers(2);
0066     error('Duration of data in params.tapers is inconsistent with movingwin(1), modify params.tapers(2) to proceed')
0067 end
0068
0070 clear err
0071 [mintime,maxtime]=minmaxsptimes(data);
0072 tn=(mintime+movingwin(1)/2:movingwin(2):maxtime-movingwin(1)/2);
0073 Nwin=round(Fs*movingwin(1)); % number of samples in window
0074 % Nstep=round(movingwin(2)*Fs); % number of samples to step through
0076 f=getfgrid(Fs,nfft,fpass); Nf=length(f);
0077 params.tapers=dpsschk(tapers,Nwin,Fs); % check tapers
0078 %K=size(params.tapers,2);
0079 nw=length(tn);
0080 if trialave==0; dS=zeros(length(phi),nw,Nf,C); else dS=zeros(length(phi),nw,Nf); end;
0081 for n=1:nw;
0082    t=linspace(tn(n)-movingwin(1)/2,tn(n)+movingwin(1)/2,Nwin);
0083    datawin=extractdatapt(data,[t(1) t(end)]);
0084    [ds,f]=mtdspectrumpt(datawin,phi,params,t);
0085    dS(:,n,:,:)=ds;
0086 end;
0087 sz=size(ds);
0088 dS=squeeze(dS);
0089 % if length(sz)==3;
0090 %    dS=permute(dS,[2 1 3 4]);
0091 % elseif length(phi)>1
0092 %    dS=permute(dS,[2 1 3]);
0093 % end;
0094 t=tn;```

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