G=tf(1,conv([1,0.1,5],[1,2,3,4]));
step(G);

t=0:.01:5; y=step(G,t); plot(t,y)

t=0:0.111:40; y=step(G,t); t1=0:0.2:40; y1=step(G,t1);
t2=0:0.4:40; y2=step(G,t2); t3=0:0.8:40; y3=step(G,t3);
t4=0:1.2:40; y4=step(G,t4);
plot(t,y,t1,y1,t2,y2,t3,y3,t4,y4)