clc
clear all

fpr = 1000;
N = 800;
dt = 1/fpr;
T = N * dt;
t =  dt * (0:N-1);
x = 1 * cos(2*pi*44.44*t)+0.0001 * cos(2* pi * 77.77 * t);% + cos(randn(1,N));
stem(x); pause;
w = chebwin(N, 120)';
stem(w); pause;
x = x.*w;
stem(x);
pause;
fl = 0:0.1:fpr;
for k=1:length(fl)
    X1(k) = sum(x.*exp(-j * 2 * pi * fl(k)*t))/N;
end
f1 = 1/(N*dt);
f2 = f1 * (0:N-1);
for k=1:length(f2)
    X2(k) = sum(x.*exp(-j * 2 * pi * f2(k) * t))/N;
end

plot(fl, abs(X1),  'b-', f2, abs(X2), 'ro'); pause;
plot(fl, 20*log10(abs(X1)), 'b-', f2, 20*log10(abs(X2)), 'ro');