Topic: Control Systems
System has some poles lying on imaginary axis is
- A. Unconditionally stable
- B. Conditionally stable
- C. Unstable
- D. Marginally stable
Answer: D. Marginally stable
Explanation: If a system has non-repeated poles lying on the imaginary axis (and no poles in the right half of the s-plane), its impulse response contains oscillatory terms of constant amplitude, making the system marginally stable.