feedback(P*C,1)

I have seen in some places the feedback function is called in the way "feedback(C*P,1)".

P = 1/(s^2 + 10*s + 20);

Kp = 300;

Kd = 10;

C = pid(Kp,0,Kd)

T = feedback(C*P,1)

t = 0:0.01:2;

step(T,t)

After searching for in the documentation,

sys = feedback(sys1,sys2)

sys = feedback(sys1,sys2,feedin,feedout)

sys = feedback(sys1,sys2,'name')

sys = feedback(___,sign)

I could not find a match.

could someone explain how feedback(C*P,1) is interpreted here?

Answer 1

[Xudong Sun]

It seems 1 mean identity here?