Model | ACF | PACF |
AR(p) | exponential or sinusoidal decay to zero | spikes cut off to zero after lag p |
MA(q) | spikes cut off to zero after lag q | exponential or sinusoidal decay to zero |
ARMA(p, q) | exponential or sinusoidal decay to zero after lag q | exponential or sinusoidal decay to zero after lag p |