How do we think about signal delay when the phase is nonlinear? Group delay ∠H(j0) When the signal is narrow-band and concentrated near wo, LH(w) linear with w near wo, then d∠H(j) instead ∠H(ju) reflects the time delay or frequencies " near Wo ∠H(j)≈LH(0)-r(u0)(u-w0)=0-r(uo): T(w)=ch(u))=Group Delay or w near wo H(ju)≈|H(juo)e t HHow do we think about signal delay when the phase is nonlinear? Group Delay φ