clear;close;
N=50;psi_deg=30;
k=1:N;f=0.1;theta=30;A_x=sin(theta*pi/180);A_y=cos(theta*pi/180);
psi_x=fix(rand(size(k))*psi_deg)*pi/180;
psi_y=fix(rand(size(k))*psi_deg)*pi/180;
x=A_x*cos(2*pi*f*k+psi_x);
y=A_y*cos(2*pi*f*k+psi_y);
subplot(211);
plot(x,y,'-');grid;title('A');xlabel('Analog');

u=ones(size(x));
A(:,1)=x';A(:,2)=u';
p=inv(A'*A)*A'*y';
X=linspace(min(x),max(x),100);
Y=p(1)*X+p(2);
subplot(212);
plot(x,y,'o',X,Y);grid on;title('B');xlabel('Digital');