TIPE synthese sonore: analyse/resynthese additive par temps fréquence

    %===================================================

    % ( classic analysis part of a phase vocoder )

    % Take a frame, and window it

    

    X  = h.*E((loop-1) * La + 1loop-1)*La + Nfft); 

   

    % XI is the amplitude spectrum, and Phia2 the phase spectrum.

    

    tX    = fft(X, Nfft);

    Xi    = abs(tX);

    Phia2 = angle(tX);

    

    %=================================================================

    % the part which actually does the time scaling

    

    % One compute the actual pulsations, and shift them. The tricky part 

    % is here...

    

    omega = mod( (Phia2-Phia1)-2*pi*([0:Nfft-1].')/Nfft * La + pi, 2*pi) - pi;

    omega = 2 * pi * ([0:Nfft-1].') / Nfft + omega / La;

    Phis2 = Phis1 + lss_frame*omega;

 

    % The new phases values  :

    

    Phis1 = Phis2;

    Phia1 = Phia2;

    

    %===========================================================

    %  Synthetise the frame, thanks to the 

    % computed phase and amplitude spectrum :

    % ( classic synthesis part of a phase vocoder )

    

    tfs = Xi.*exp(j*Phis2);

    Xr  = real(ifft(tfs)).*h;

    

    % overlapp-add the synthetised frame Xr 

    

    S((loop-1)*lss_frame+1 : (loop-1) * lss_frame + Nfft) ...

      = S((loop-1) * lss_frame + 1loop-1) * lss_frame + Nfft) + Xr;