Transfer Functions, Poles and Response — Cheat sheet

Choose “Save as PDF” in the print dialog.
On this page

Core rule

G(s)=Y(s)/U(s)with zero initial conditions.G(s)=Y(s)/U(s)\quad\text{with zero initial conditions}.

Watch for

Frequency response uses G(iω)G(i\omega) after stable transients have decayed. A pole-zero cancellation can hide an unstable internal mode, so transfer behavior alone should not be treated as a complete state-stability proof.