gabmul.m

linear time－frequency toolbox

function h=gabmul(f,c,p3,p4,p5)
%GABMUL  Gabor multiplier.
%   Usage:  h=gabmul(f,c,a);
%           h=gabmul(f,c,g,a);
%           h=gabmul(f,c,ga,gs,a);
%
%   Input parameters:
%         f     : Input signal
%         c     : symbol of Gabor multiplier
%         g     : analysis/synthesis window
%         ga    : analysis window
%         gs    : synthesis window
%         a     : Length of time shift.
%   Output parameters:
%         h     : Output signal
%
%   GABMUL(f,c,g,a) will filter f by a Gabor multiplier determined by
%   the symbol c over the rectangular time-frequency lattice determined by 
%   a and M, where M is deduced from the size of c.
%   The window g will be used for both analysis and synthesis.
%
%   GABMUL(f,c,a) will do the same using an optimally concentrated, tight
%   Gaussian as window function.
%
%   GABMUL(f,c,gs,ga,a) will do the same using the window ga for
%   analysis and gs for synthesis.
%
%   SEE ALSO: DGT, IDGT, CANDUAL, CANTIGHT, GMEIGS, CANTIGHT
%
%   EXAMPLES: EXAMP_GABMUL


error(nargchk(3,5,nargin));

M=size(c,1);
N=size(c,2);

if nargin==3
  a=p3;
  L=a*N;
  ga=cantight(a,M,L);
  gs=ga;
end;

if nargin==4;
  ga=p3;
  gs=p3;
  a=p4;
  L=a*N;
end;

if nargin==5;  
  ga=p3;
  gs=p4;
  a=p5;
  L=a*N;
end;


[nga mga] = size(ga);
if nga ~= 1 && mga~= 1 
   error('Window ga should be a vector')
end  
nga = length(ga);

[ngs mgs] = size(gs);
if ngs ~= 1 && mgs~= 1 
   error('Window gs should be a vector')
end  
ngs = length(ga);

[nf mf] = size(f);
if nf ~= 1 && mf~= 1 
   error('Signal f should be a vector')
end  

assert_squarelat(a,M,'GABMUL',0);

[coef,Ls]=dgt(f,ga,a,M);
h=idgt(coef.*c,gs,a,Ls);