% 自適應方向圖測試
clear;
close all
%----陣列參數-------------
M=10;
N=3;
snr=20;
L=100;
ddd=0.5;
signal_doa=[30 55 20];
%----產生數據-------------
signal_a=10^(snr/10);
S=randn(N,L)+i*randn(N,L);
noise=randn(M,L)+i*randn(M,L);
A=exp(i*2*pi*ddd*(0:M-1)'*sin(signal_doa*pi/180));
X=A*S*signal_a+noise;
%----應用算法計算權-------------
R=X*X'/L;
a0=exp(i*2*pi*ddd*(0:M-1)'*sin(-40*pi/180));
W=inv(R)*a0;
%----應用權得到方向圖-------------
ddoa=-90:90;
steer=exp(i*2*pi*ddd*(0:M-1)'*sin(ddoa*pi/180));
p=W'*steer;
p1=(hamming(M))'*steer;
p2=(chebwin(M,30))'*steer;
%----畫圖-------------
figure;hold on;grid on;box on
% plot(ddoa,20*log10(abs(p/max(abs(p)))));
plot(ddoa,20*log10(abs(p1/max(abs(p1)))),'r');
plot(ddoa,20*log10(abs(p2/max(abs(p2)))),'k');
% legend('自適應方向圖')
legend('海明窗','海寧窗')
axis([-90 90 -100 0])