Hi, i'm trying to analyze the phase of a signal in order to resynthesize it. I want to
fill the fft buffer in a zero-phase way in order to collect the correct phase information. The
problem is that the phase result is incorrect.
Here there is an example of the script that i use

f0=120.3;
fase0=0.3;
Fs=44100;
durata=0.04; %sec
N=round(durata*Fs/2)*2+1;
t=[0:N-1]/Fs;
t=t';
A=3;
x=A.*cos(2*pi*f0*t+fase0);

%calcolo spettro
M=2^16;
w = blackman(N);
xw=x.*w;

%riempimento buffer a fase zero
xzp = [xw((N-1)/2+1:N); zeros(M-N,1); xw(1:(N-1)/2)];
%calcolo fft
X = fft(xzp);
%normalizzazione
X=X./ (N*(sum(w)/length(w)));

fase=angle(X);

Anyone can help me to solve this problem?