信号与系统_MATLAB_实验_课后习题答案

1、精选文档第三章练习题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(t>0)=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、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');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+

3、1)=F(n)+T*f(n); end 验证如下：t=-1:0.01:4; e=zeros(size(t); e=(t>-1/2&t<1);z,zz=intl(e,t,-1);figure;plot(zz,z);第四章练习题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*ex

4、p(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; fs2=fs2+OMG/2/pi/K1*exp(j*kron(t2,omg.')*X2; figure; subplot(2,2,1);plot(omg,abs(X1),'r'); xlabel('Frequency'),ylabel('Amplitude&#

5、39;)title('单个锯齿周期幅频特性曲线');subplot(2,2,2); plot(t1,fs1,'r'); xlabel('Time'),ylabel('Amplitude')title('Function after recovered');subplot(2,2,3);plot(omg,abs(X2),'r'); xlabel('Frequency'),ylabel('Amplitude')title('五个锯齿周期幅频特性曲线');s

6、ubplot(2,2,4);plot(t2,fs2,'r'); xlabel('Time'),ylabel('Function after recovered')title('Function after recovered'); 2、fsana函数如下：function F=fsana(t,f,N);omg1=2*pi/(max(t)-min(t); k=-N:N'F=1/length(t)*exp(-j*kron(k*omg1,t.')*f;fssyn函数如下：function f=fssyn(F,t)omg1

7、=2*pi/(max(t)-min(t);N=floor(length(F)/2);k=-N:N;f=exp(j*kron(t,k*omg1)*F;验证如下:clcclearclose allT1=1; N1=256; t=linspace(0,T1-T1/N1,N1)' f=1-2*t; subplot(3,1,1); plot(t,f);title('验证原函数')N=25;F1=fsana(t,f,N); subplot(3,1,2);stem(abs(F1),'s');title('前N项傅立叶级数系数幅度曲线')f2=fssyn

8、(F1,t) ;subplot(3,1,3); plot(t,f2);xlabel('times'),ylabel('Amplitude');title('傅立叶逆变换后时域函数'); 第五章练习题1、(a) Residue计算a1=1,5,6;b1=4,5;r1,p1,k1=residue(b1,a1);t=0:0.01:10;e1=zeros(size(t);for n=1:size(r1);e1=e1+r1(n)*exp(p1(n)*t);end;figure;subplot(1,2,1);plot(t,e1);title('res

9、idue计算');xlabel('t/s');ylabel('u/v');lism仿真sys1=tf(4,5,1,5,6);t=0:0.01:10;delta=zeros(size(t);delta(t=0)=100;h1=lsim(sys1,delta,t);subplot(1,2,2);plot(t,h1);title('lism仿真');xlabel('t/s');ylabel('u/v');Residue计算和lism仿真结果相同（b）Residue计算t=0,0.01,10;delta=zeros

10、(size(t);delta(t=0)=100;e2=sin(t);figure;subplot(2,1,1);plot(t,e2);title('residue计算');xlabel('t/s');ylabel('u/v'); lism仿真sys1=tf(1,0,2,1,0,1);t=0:0.01:10;delta=zeros(size(t);delta(t=0)=100;h2=lism(sys1,delta,t);subplot(2,1,2);plot(h,t2);axis(0,10,-1,1);title('lism仿真')

11、;xlabel('t/s');ylabel('u/v');Residue计算和lism仿真结果相同2、S=isstable(sys)函数：Function s=isstable(sys);X=ploe(sys);S=1;For n=1:Size(x) If x(n)>0 S=0;break; End;End; 稳定系统：Sys=tf(1,1,2);S=isstable(sys);S= 1不稳定系统：Sys=tf(1,1,-2);S=isstable(sys);S= 0第七章练习题1、a=1,0.5,-0.2,-0.1;b=1,-0.3;n=0:10'hi,t=impz(b,a,n);subplot(1,2,1);stem(n,hi);u=(n>=0);hn=filter(b,a,u);subplot(1,2,2);stem(n,hn);2、n