Linear, Time-Invariant, Causality, Stability 線性、非時變、因果性、穩定性

linear system 線性系統
time-invariant system 非時變系統
causality 因果性
stability 穩定性

For stability,
bounded-input bounded-output (BIBO) 有界輸入有界輸出

unit circle 單位圓
region of convergence 收斂域

When the ROC of z-transform X(z) includes the unit circle, x[n] is:

stable 穩定
absolutely summable 絕對可加