Model

ACF

PACF

MA(q)

Cuts off after lag q

Infinite exponential decay and/or damped sinusoid—tailing off

AR(p)

Infinite exponential decay and/or damped sinusoid—tailing off

Finite-cuts off after lag p

ARMA(p,q)

Infinite exponential decay and/or damped sinusoid—tailing off

Infinite exponential decay and/or damped sinusoid—tailing off