典型环节的时域响应的实验报告

subplot(2,2,3); stem(T,xn); ylabel('x(n)'); xlabel('n');

xrtt=[];

for m=0:length(xn)-1 t1=-1:0.01:4;

xrtm=xn(m+1)*sin(pi*(t1-m/fs)*fs+eps)./(pi*(t1-m/fs)*fs+eps); xrtt=[xrtt;xrtm]; end

xrt=sum(xrtt); subplot(2,2,4); plot(t1,xrt); ylabel('xr(t)'); xlabel('t'); figure

t = 0:0.001:4; xt=cos(4*pi*t); subplot(2,2,1); plot(t,xt); ylabel('x(t)'); xlabel('t'); fs = 3; T = 0:1/fs:1; xn=cos(4*pi*T); subplot(2,2,2); t1 = -4:0.001:4;

ht = sin(pi*t1*fs+eps)./(pi*t1*fs+eps); plot(t1,ht); ylabel('hr(t)'); xlabel('t'); subplot(2,2,3); stem(T,xn); ylabel('x(n)'); xlabel('n');

xrtt=[];

for m=0:length(xn)-1 t1=-1:0.01:4;

xrtm=xn(m+1)*sin(pi*(t1-m/fs)*fs+eps)./(pi*(t1-m/fs)*fs+eps); xrtt=[xrtt;xrtm]; end

xrt=sum(xrtt); subplot(2,2,4); plot(t1,xrt); ylabel('xr(t)'); xlabel('t');

10.50-0.5-110.5hr(t)0012t34-0.5-4x(t)-20t2410.521x(n)0-0.5-1xr(t)00.5n10-1-2-20t24

10.50-0.5-110.5hr(t)0012t34-0.5-4x(t)-20t2410.521x(n)0-0.5-1xr(t)000.5n1-1-20t24

5、已知序列x[k]={1,3,2,-5;k=0,1,2,3}分别取N=2,4,8对其频谱进行抽样，再有频域抽样点恢复时域序列，观察时域序列的混叠。

x=[1,3,2,-5]; n=0:3; N1 = 2; N2 = 4; N3 = 8; L=4; N = 256;

omega = [0:N-1]*2*pi/N;

Xk = 1 + 3*exp(-j*omega) + 2*exp(-j*2*omega) -5*exp(-j*3*omega); plot(omega./pi,abs(Xk)); omega1 = [0:N1-1]*2*pi/N1;

Xk1 = 1 + 3*exp(-j*omega1) + 2*exp(-j*2*omega1) - 5*exp(-j*3*omega1); figure

xr1=real(ifft(Xk1)); stem(xr1);

omega2 = [0:N2-1]*2*pi/N2;

Xk2 = 1 + 3*exp(-j*omega2) + 2*exp(-j*2*omega2) - 5*exp(-j*3*omega2); figure

xr2=real(ifft(Xk2)); stem(xr2);

omega3 = [0:N3-1]*2*pi/N3;

Xk3= 1 + 3*exp(-j*omega3) + 2*exp(-j*2*omega3) - 5*exp(-j*3*omega3); figure

xr3=real(ifft(Xk3)); stem(xr3);

98765432100.20.40.60.811.2Omega/PI1.41.61.82