iwindowft.sci

小波分解源代码

function sig = IWindowFT(specgm,w,Name)
// IWindowFT -- Inverse Window Fourier Transform
//  Usage
//    sig = IWindowFT(specgm,w,Name)
//  Inputs
//    specgm    Window Fourier Transform of sig, complex matrix
//    w        window half-length used to construct specgm
//    Name     string: 'Rectangle', 'Hanning', 'Hamming',
//             'Gaussian', 'Blackman' 
//              name of window used to construct specgm
//  Outputs
//    sig      1-d signal
//  Side Effects
//    none
//  Description
//     supposes signal is non-periodic, i.e. zero-padded
//     reconstruction is not exact in the border region, but it is
//     exact in the center
//  See Also
//    WindowFT
//  References
//    Mallat, "A Wavelet Tour in Signal Processing"; 
//            4.2.3 Discrete Windowed Fourier Transform.
//
//  Copyright Aldo I Maalouf

[n,nw] = size(specgm);
f = zeros(3*n,1);
totseg = zeros(3*n,1);
win    = MakeWindow(Name,w);
win    = win(:);
wind = zeros(3*n,1);
wind(n+1-w:n+1+w,1) = win;

for i = 1:nw,
	totseg(n+1:2*n) = mtlb_ifft(specgm(:,i)');
	f = f + wind.*totseg;
	wind = rshift(wind')';
end;
f = f(n+1:2*n);
sig = f/max(svd(wind))^2.;
endfunction