試題詳解

複選題
8. Which of the following statements regarding system robustness are true?
(A) A closed-loop system must beco ome unstable when the transmission lag is large enough.
(B) A closed-loop system must be stable when both gain margin and phase margin are positive.
(C) The gain margin is always ininite for second-order systers.
(D) It is possible to have infinite phase margin.
(E) Reduction of gain increases the gain margin without sacrifcing the steady-state error.