ADAPTIVE FILTER INCLUDING CONTROLLED TAP COEFFICIENT LEAKAGE

In adaptive filters, under certain incoming signal conditions the tap coefficients tend to drift toward relatively large values. This condition has been countered by introducing so-called leakage into the tap coefficients which tends to drive them toward zero. Introduction of leakage is desirable under certain incoming signal conditions and not others. Indeed, during intervals that partial band energy, e.g., single frequency tones, multifrequency tones and the like, is incoming to the filter there is a need to introduce a relatively large leakage value into the tap coefficients. However, during intervals that whole band energy, e.g., speech or noise, is incoming to the filter no leak is desired or needed. This is realized by detecting intervals when partial band energy is incoming to the filter and controllably increasing the leakage value during those intervals.