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mtdspecgramc

PURPOSE

Multi-taper derivative of the time-frequency spectrum - continuous process

SYNOPSIS

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

DESCRIPTION

``` Multi-taper derivative of the time-frequency spectrum - continuous process

Usage:

[dS,t,f]=mtdspecgramc(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        (in form samples x channels/trials or a single vector) -- 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 - required
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/channels 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:
• mtdspectrumc Multi-taper frequency derivative of the spectrum - continuous process
This function is called by:

SOURCE CODE

```0001 function [dS,t,f]=mtdspecgramc(data,movingwin,phi,params)
0002 % Multi-taper derivative of the time-frequency spectrum - continuous process
0003 %
0004 % Usage:
0005 %
0006 % [dS,t,f]=mtdspecgramc(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 %
0013 %       data        (in form samples x channels/trials or a single vector) -- 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 - required
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 Fs/2
0053 %           trialave - (average over trials/channels when 1, don't average when 0) - optional. Default 0
0054 % Output:
0055 %       dS      (spectral derivative in form phi x time x frequency x channels/trials if trialave=0;
0056 %               in form phi x time x frequency if trialave=1)
0057 %       t       (times)
0058 %       f       (frequencies)
0059
0060 if nargin < 3; error('Need data, window parameters and angle'); end;
0061 if nargin < 4; params=[]; end;
0062
0063 if length(params.tapers)==3 & movingwin(1)~=params.tapers(2);
0064     error('Duration of data in params.tapers is inconsistent with movingwin(1), modify params.tapers(2) to proceed')
0065 end
0066
0068 clear err
0069 data=change_row_to_column(data);
0070 [N,C]=size(data);
0071 Nwin=round(Fs*movingwin(1)); % number of samples in window
0072 Nstep=round(movingwin(2)*Fs); % number of samples to step through
0074 f=getfgrid(Fs,nfft,fpass); Nf=length(f);
0075 params.tapers=dpsschk(tapers,Nwin,Fs); % check tapers
0076 params.tapers=tapers;
0077 winstart=1:Nstep:N-Nwin+1;
0078 nw=length(winstart);
0079 if trialave==0; dS=zeros(length(phi),nw,Nf,C); else dS=zeros(length(phi),nw,Nf); end;
0080 for n=1:nw;
0081    indx=winstart(n):winstart(n)+Nwin-1;
0082    datawin=data(indx,:);
0083    [ds,f]=mtdspectrumc(datawin,phi,params);
0084    dS(:,n,:,:)=ds;
0085 end;
0086 dS=squeeze(dS);
0087 sz=size(dS);
0088 % if length(sz)==3;
0089 %    dS=permute(dS,[2 1 3 4]);
0090 % elseif length(phi)>1
0091 %    dS=permute(dS,[2 1 3]);
0092 % end;
0093 winmid=winstart+round(Nwin/2);
0094 t=winmid/Fs;```

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