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PHASE DELAY AND GROUP DELAY

The Fourier-domain ratio of a wave seen at B divided by a wave seen at A can be regarded as a filter. The propagation velocity is the distance from A to B divided by the delay. There are at least two ways to define the delay, however.

Phase delay
Group delay
Group delay as a function of the FT
Observation of dispersive waves
Group delay of all-pass filters

Stanford Exploration Project
10/21/1998