Interpreting the Phase Response

• What does it mean to have a phase response of
  $$\Theta(\omega) = -\frac{\omega T}{2} = -\pi\frac{f}{f_s}, \qquad \vert f\vert\le f_s/2?$$

• We see, again but perhaps more clearly, that the phase response is linear in frequency.

• In general, to obtain the phase delay (time delay) in seconds, divide by $-\omega$:
  $$P(\omega) \triangleq -\frac{\Theta(\omega)}{\omega}$$   seconds$$.$$