武汉理工大学信号与系统实验答案.docVIP

1-1-1 clear close all dt=0.01;( dt=0.2;) t=-2:dt:2; x=sin(2*pi*t); plot(t,x) title(sinusoidal singnalx(t)) xlabel(Time t(sec)) 1-2 t=-5:0.001:5; x=exp(-0.5*t).*u(t); y=exp(-0.5*(1.5*t+3)).*u(1.5*t+3); subplot(211) plot(t,x) title(x(t)) subplot(212) plot(t,y) title(y(t)=x(1,5*t+3)) 1-3 clear; close all; t0=0;t1=3.5;dt=0.001; t=t0:dt:t1; x1=u(t)-u(t-2); x2=u(t-1)-u(t-3); y=dt*conv(x1,x2); subplot(221) plot(t,x1) grid on title(Signal x1(t)) axis([t0,t1,0,1.5]) subplot(222) plot(t,x2) grid on title(signal x2(t)) axis([t0,t1,0,1.5]) subplot(212) t=t0:dt:2*t1; plot(t,y) grid on title(The convolution of x1(t) and x2(t)) axis([2*t0,2*t1,0,2.5]) xlabel(Time t(sec)) + 2-1 clear close all num=input(Type in the right coeffcient vector of differential equation:); den=input(Type in the left coefficient vector of differential equation:); t=0:0.01:10; x=input(Type in the expression of the input signal x(t):); lsim(num,den,x,t) 运行过程： Type in the right coeffcient vector of differential equation:8 Type in the left coefficient vector of differential equation:[1,3,2] Type in the expression of the input signal x(t):(exp(-2*t)-exp(-3*t)).*u(t) 3-1 clear close all T=2; dt=0.00001; t=-2:dt:2; x1=(u(t+1)-u(t-1-dt)).*abs(t); x=0; for m=-1:1 x=x+u(t-m*T)-u(t-1-m*T-dt); end w0=2*pi/T; N=10; L=2*N+1; for k=-N:N; ak(N+1+k)=(1/T)*x1*exp(-j*k*w0*t)*dt; end phi=angle(ak); 运行结果： ak = Columns 1 through 6 0.0000 - 0.0000i -0.0025 - 0.0000i 0.0000 + 0.0000i -0.0041 + 0.0000i 0.0000 + 0.0000i -0.0081 - 0.0000i Columns 7 through 12 0.0000 - 0.0000i -0.0225 + 0.0000i 0.0000 - 0.0000i -0.2026 + 0.0000i 0.5000 -0.2026 - 0.0000i Columns 13 through 18 0.0000 + 0.0000i -0.0225 - 0.0000i 0.0000 + 0.0000i -0.0081 + 0.0000i 0.0000 - 0.0000i -0.0041 - 0.0000i Columns 19 through 21 0.0000 - 0.0000i -0.0025 + 0.0000i 0.0000 + 0.0000i 3-2 b=input(b=); a=input(a=); [H,w]=freqs(b,a); Hm=abs(H); phai=angle(H); hr=real(H); Hi=imag(H)