# 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...).
                        -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      (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:

- dpsschk Helper function to calculate tapers and, if precalculated tapers are supplied,
- getfgrid Helper function that gets the frequency grid associated with a given fft based computation
- getparams Helper function to convert structure params to variables used by the
- 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:

- testscript function testscript(pname,direction,movingwin,segave,params,fscorr)

## 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...).
    0044 %                    -1 corresponds to no padding, 0 corresponds to padding
    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
    0069 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
    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
    0075 nfft=max(2^(nextpow2(Nwin)+pad),Nwin);
    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;