信号及系统 MATLAB 实验 课后习题答案.docVIP

3-1 a=[1,1,1]; b=[1,1]; sys=tf(b,a); t=[0:0.01:10]; figure; subplot(2,2,1); step(sys); subplot(2,2,2); x_step=zeros(size(t)); x_step(t0)=1; x_step(t==0)=1/2; lsim(sys,x_step,t); subplot(2,2,3); impulse(sys,t); title(Impulse Response); xlabel(Time(sec)); ylabel(Amplitude); subplot(2,2,4); x_delta=zeros(size(t)); x_delta(t==0)=100; [y1,t]=lsim(sys,x_delta,t); y2=y1; plot(t,y2); title(Impulse Response); xlabel(Time(sec)); ylabel(Amplitude); 3-2 函数int1如下： function [F,tF]=int1(f,tf,a) T=tf(2)-tf(1); F=zeros(size(tf)); tF=zeros(size(tf)); tF=tf; for n=1:length(tf)-1; F(n+1)=F(n)+T*f(n); end 验证如下： t=[-1:0.01:4]; e=zeros(size(t)); e=(t-1/2t1); [z,zz]=int1(e,t,-1); figure; plot(zz,z); 4-1 T1=1; N1=10000; t1=linspace(0,T1-T1/N1,N1); f1=1-2*t1; OMG=32*pi; K1=100; omg=linspace(-OMG/2,OMG/2-OMG/K1,K1); X1=T1/N1*exp(-j*kron(omg,t1.))*f1; fs1=OMG/2/pi/K1*exp(j*kron(t1,omg.))*X1; T2=5; N2=10000; t2=linspace(0,T2-T2/N2,N2); fs2=0*t2; f2=sawtooth(t2*2*pi,0); X2=T2/N2*exp(-j*kron(omg,t2.))*f2;