Laplace Transform & System Stability

Oppenheim & Willsky — Continuous-Time Systems

System Preset

Pole 1 (Manual)

Zero

Input & Stability

STABLE — Poles in LHP
σmax (dominant)
Natural freq ωn
Damping ζ
Laplace Transform
H(s) = N(s)/D(s)

BIBO Stability:
ROC includes jω-axis
⇔ all poles in LHP (σ < 0)

2nd Order System:
H(s) = ωn²/(s²+2ζωns+ωn²)
ζ < 1: underdamped
ζ = 1: critically damped
ζ > 1: overdamped