METHOD AND APPARATUS FOR FEEDBACK CANCELLATION IN THE PRESENCE OF TONAL SIGNALS

摘要

A system and technique for feedback cancellation. An off-line feedback estimation filter is adaptive in response to an error signal. An on-line feedback cancellation filter produces a feedback cancellation signal. The on-line feedback cancellation filter is updated by deriving on-line filter taps from taps of the off-line filter, with the update occurring when a tonality measure determined from the off-line filter taps meets a pre-defined criterion. The tonality measure may include reference to non-causal filter taps.