MATLAB--Test060901

N=4096;
FS=2000;
DT=1/FS;
t=0:DT:N*DT-DT;
f=0:FS/N:FS-FS/N
a1=1;a2=0.5;a3=2;
f1=50;f2=100;f3=300;
x=a1*sin(2*pi*f1*t)+a2*sin(2*pi*f2*t)+a3*sin(2*pi*f3*t)
z=fft(x,N)
AX=abs(z*2/N);
plot(f,AX)