tfr_create.m

linear time－frequency toolbox

function self=tfr_create(tt,a,M,awin,swin,varargin);
%TFR_CREATE   Create time-frequency representation object
%   Usage:  tfr=tfr_create(tt,a,M,awin,swin);
%
%   Input parameters:
%       tt      : Name of transform.
%       a       : Time shift.
%       M       : Number of channels.
%       awin    : Analysis window.
%       swin    : Synthesis window.
%       options : Cell array of options (optional)
%   Output:
%       tfr     : Handle to this TF representation.
%
%   This function creates a time-frequency representation
%   represented by the variable tfr.
%
%   tt can be one of: 'dgt', 'rdgt', 'rdgt2', 'dwilt',
%                     'edgt6'
%
%   awin and swin can be one of 'none','pgauss','candual','cantight'
%                               'pherm'
%
%   options can be one of 'phaselock'
%
%   
%
%   SEE ALSO:  TFR_AR, TFR_SR, TFR_CLEAR

%error(nargchk(3,6,nargin)); 

if nargin<3
  error('Too few input arguments.');
end;

if nargin<=5
  options={};
end;

if nargin<=4
  swin='none';
end;

if nargin<=3
  awin='none';
end;
  

global TF_STORAGE;

% Initialise it for the first time.
if prod(size(TF_STORAGE))==0
  TF_STORAGE.next=1;
  TF_STORAGE.data={};
end;

% Get the number of the next available slot.
self=TF_STORAGE.next;

% Increse the counter so it is ready for next invocation.
TF_STORAGE.next=TF_STORAGE.next+1;

% Check tt, a and M for validity and get information
% about which DGT the transform relates to. 
dgtinfo=assert_tt(tt,a,M,'TFR_CREATE');

% Check awin and swin
[awininfo,ait]=assert_win(awin,dgtinfo,'awin','TFR_CREATE');
[swininfo,sit]=assert_win(swin,dgtinfo,'swin','TFR_CREATE');

% Both windows cannot depend on each other
if awininfo.otherdepend && swininfo.otherdepend
  error(['TFR_CREATE: Both windows cannot depend on each other.']);
end;

% Both windows cannot be specified as tight.
if ait && sit
  error(['TFR_CREATE: Both windows cannot be tight.']);
end;

% Determine is we are using a tight window. Meaning of istight is:
% 0 - no window is tight.
% 1 - analysis window is specified as tight.
% 2 - synthesis window is specified as tight.
istight=0;
if ait==1
  istight=1;
end;
if sit==1
  istight=2;
end;

% ------- parse additional options -----------
phaselock=0;

for ii=1:length(varargin)
  option=varargin{ii};
  switch(lower(option))
    case {'phaselock'}
      phaselock=1;
  end;
end;

% Determine R. Either both window have the same width, or one
% window has width zero, meaning that it is flexible.
if ~((awininfo.R*swininfo.R==0) || (awininfo.R==swininfo.R))
  error('Incorrect window combination: Windows must have the same width.')
end;

if awininfo.R==swininfo.R
  R=awininfo.R;
else
  R=awininfo.R+swininfo.R;
end;

% Load up the information.
TF_STORAGE.data{self}.tt=tt;
TF_STORAGE.data{self}.a=a;
TF_STORAGE.data{self}.M=M;
TF_STORAGE.data{self}.dgtinfo=dgtinfo;
TF_STORAGE.data{self}.w{1}=awininfo;
TF_STORAGE.data{self}.w{2}=swininfo;
TF_STORAGE.data{self}.istight=istight;
TF_STORAGE.data{self}.phaselock=phaselock;
TF_STORAGE.data{self}.R=R;

% These parameters indicate a rectangular lattice
TF_STORAGE.data{self}.s1=0;
TF_STORAGE.data{self}.s2=1;