Obtaining a desired non-zero phase shift using forward-backward filtering

摘要

Forward and backward filters in cascade establish a specified phase shift in audio or video signals. The backward filter applies its filtering in a backward direction to impart a phase shift to its backward-filtered output that is a function of frequency. The forward filter applies its filtering in a forward direction to impart a phase shift to its forward-filtered output that has the specified phase shift relative the phase shift of the backward filter. Preferably, the two filters are recursive and are applied to signals that represent overlapping segments of the audio or video information. The overlap interval is used for filter initialization.