语音伪装课程设计代码，求助

本人matlab初学者一名，老师上课布置了语音伪装的课程设计任务，有一段参考代码，看不懂，想请各位大神指教一下，分析一下中间最主要的循环的作用是什么
function Y=voice(x,f,fs);
f=round(f*fs);
d=resample(x,f,fs);
W=400;
Wov=W/2;
Kmax=W*2;
Wsim=Wov;
xdecim=8;
kdecim=2; X=d';
F=f/fs;
Ss =W-Wov;
xpts = size(X,2);
ypts = round(xpts / F);
Y = zeros(1, ypts);
xfwin = (1:Wov)/(Wov+1);
ovix = (1-Wov):0; newix = 1:(W-Wov);
simix = (1:xdecim:Wsim) - Wsim;
padX = [zeros(1, Wsim), X, zeros(1,Kmax+W-Wov)];
Y(1:Wsim) = X(1:Wsim); lastxpos = 0; km = 0;
for ypos = Wsim:Ss:(ypts-W);
xpos = round(F * ypos);
kmpred = km + (xpos - lastxpos);
lastxpos = xpos;
if (kmpred <= Kmax)
km = kmpred;
else
ysim = Y(ypos + simix);
rxy = zeros(1, Kmax+1);
rxx = zeros(1, Kmax+1);
Kmin = 0;
for k = Kmin:kdecim:Kmax;
xsim = padX(Wsim + xpos + k + simix);
rxx(k+1) = norm(xsim);
rxy(k+1) = (ysim * xsim');
end
Rxy = (rxx ~= 0).*rxy./(rxx+(rxx==0));
km = min(find(Rxy == max(Rxy))-1);
end
xabs = xpos+km;
Y(ypos+ovix) = ((1-xfwin).*Y(ypos+ovix)) + (xfwin.*padX(Wsim+xabs+ovix));
Y(ypos+newix) = padX(Wsim+xabs+newix);
end
end