exprience2_2.m

matlab exprience,M文件,实验代码

t=0:0.05:10-0.05; %0.05s means fs=20Hz
xn=exp(-t);
L_100=100;
L_20=20;
L_N=200;
N=200;
for i=1:L_100;
    x_L_100(i)=xn(i);
end
for i=1:L_20;
    x_L_20(i)=xn(i);
end
x_L_100_pro=[x_L_100 zeros(1,N-L_100)]; %consequence add zeros to 200
x_L_20_pro=[x_L_20 zeros(1,N-L_20)];
n=[0:1:N-1];
k=[0:1:N-1];
WN=exp(-j*2*pi/N);
nk=n'*k;
WNnk=WN.^nk;
Xk_L_100=x_L_100_pro*WNnk;
Xk_L_20=x_L_20_pro*WNnk;
Xk=xn*WNnk;
subplot(311)
stem(Xk_L_100)
title('L=100 point spectrum')
subplot(312)
stem(Xk_L_20)
title('L=20 point spectrum')
subplot(313)
stem(Xk)
title('original signal spectrum')