Group Delay
Definition
The frequency-dependent time delay experienced by the envelope of a narrowband spectral component when propagated through a linear time-invariant network, defined as τg(ω) = −dφ(ω)/dω where φ(ω) is the network phase response; units: seconds. Group delay quantifies how phase varies with angular frequency and predicts time-domain dispersion and pulse distortion for band-limited signals.