Adaptive filter divergence control in echo cancelers by means of amplitude distribution evaluation with configurable hysteresis

摘要

A configurable adaptive filter that is used for echo cancellation is disclosed, which includes a method of detecting a voice or no-voice signal. The presence of a voice or no-voice signal is determined by calculating a histogram of signal amplitude value over a period of time. If this histogram has more than a predefined number of samples that are above a threshold then the signal is classified as no-voice or periodic otherwise the signal is classified as a voice signal. A variable maximum amplitude limit and lower amplitude thresholds are disclosed to detect a voice or no-voice from the histogram signal faster than traditional methods utilized in echo cancelers. A configurable hysteresis time is used to ensure the signal register primarily contains voice signal when the filter coefficients of the echo canceler are allowed to adapt.