系统结构图如下图所示，试求其闭环传递函数。(matlab7.1)

s=tf('s');
G1=30/s^2/(01s+1);
H=4s;
G1H=feedback(G1,H)
feedback(50G1H,1)

结果
Transfer function:
1500
----------------------------
01 s^3 + s^2 + 120 s + 1500

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