exprience2_1.m

matlab exprience,M文件,实验代码

t=0:0.001:0.2;  %dt=0.001s so the fs=1000Hz
xt=sin(2*pi*50*t)+sin(2*pi*120*t);
subplot(411)
plot(t,xt)
title('origin sinal')
K=0.2/0.001+1;
noise=randn(1,K);
xn=xt+noise;
subplot(412)
plot(t,xn)
title('sinal added gass noise')
N=1024;
n=0:N-1;
xnt=sin(2*pi*50*0.001*n)+sin(2*pi*120*0.001*n);
nn=randn(1,N);
xnn=xnt+nn;
subplot(413)
stem(n,xnn);
title('1024 window')
k=0:N-1;
WN=exp(-j*2*pi/N);
nk=n'*k;
WNnk=WN.^nk;
Xk=xnn*WNnk;
subplot(414)
stem(k,abs(Xk))
title('DFT spectrum')