21.510.50-0.5-1-1.5-2-2-1.5-1-0.500.511.52>> k=-6:5;
>> x=[-3,-2,3,1,-2,-3,-4,2,-1,4,1,-1]; >> stem(k,x)
43210-1-2-3-4-6-4-20246>> k=-2:9;
>> x=[-3,-2,3,1,-2,-3,-4,2,-1,4,1,-1]; >> stem(k,x)
43210-1-2-3-4-20246810>> k=-4:7;x=[-3,-2,3,1,-2,-3,-4,2,-1,4,1,-1]; >> xk=fliplr(x); >> k1=-fliplr(k); >>stem(k1,xk)
43210-1-2-3-4-8-6-4-2024
第三单元
1）>> ts=0;te=5;dt=0.01; >> sys=tf([2 1],[1 3 2]); >> t=ts:dt:te;
>> x=exp(-3*t).*(t>=0); >> y=lsim(sys,x,t); >> plot(t,y);
>> xlabel('Time(sec)') >> ylabel('y(t)')
0.30.250.20.15y(t)0.10.050-0.05012Time(sec)345
>> ts=0;te=5;dt=0.0001; >> sys=tf([2 1],[1 3 2]); >> t=ts:dt:te;
>> x=exp(-3*t).*(t>=0); >> y=lsim(sys,x,t); >> plot(t,y);
>> xlabel('Time(sec)') >> ylabel('y(t)')
0.30.250.20.15y(t)0.10.050-0.05012Time(sec)345
4）x=[0.85,0.53,0.21,0.67,0.84,0.12]; k1=-2:3;
h=[0.68,0.37,0.83,0.52,0.71]; k2=-1:3; y=conv(x,h);
k=(k1(1)+k2(1)):(k1(end)+k2(end)); stem(k,y);