samer@32: function wig = wigner(sig,m,l,k,win)
samer@32: % Wigner -- Wigner-Ville Distribution. This version
samer@32: %           operates on an entire signal in a vector. 
samer@32: %  Usage
samer@32: %    wig = wigner(sig,m,l,k,win)
samer@32: %  Inputs
samer@32: %    sig    1-d signal
samer@32: %    m      half window length (must be power of 2)
samer@32: %    l      number of frequencies (ie rows in output)
samer@32: %    k      window step (defaults to 1)
samer@32: %    win    half window of size m+1
samer@32: %  Outputs
samer@32: %   wig     complex-valued matrix representing the Wigner-Ville
samer@32: %           distribution of zero-extended signal with rows corresponding
samer@32: %           to frequencies and columns corresponding to times.
samer@32: %
samer@32: %  Side Effects
samer@32: %   Image Plot of the Wigner-Ville distribution
samer@32: %
samer@32: 
samer@32: sig = sig(:);
samer@32: n   = length(sig);
samer@32: 
samer@32: if nargin<4 k   = 1; end
samer@32: if nargin<3 l   = m+1; end
samer@32: if nargin<5 win = ones(m+1,1); end
samer@32:    
samer@32: f   = [zeros(m,1); sig; zeros(m,1)];
samer@32: wig = zeros(l,floor(n/k));
samer@32: ix  = 0:m;
samer@32: 
samer@32: col=1;
samer@32: for t=1:k:n,
samer@32:     tplus    = m + t + ix;
samer@32:     tminus   = m + t - ix;
samer@32:     R = win .* ( f(tplus) .* f(tminus) );
samer@32:     x = [ R(1:m); R(m+1:-1:2) ];
samer@32:     y = fft(x);
samer@32:     wig(:,col) = real(y(1:l));
samer@32:     col = col+1;
samer@32: end
samer@32: