Voice activity detection method and device

Abstract

A method and a circuit arrangement for automatic voice activity detection on the basis of the wavelet transformation. A voice activity detection circuit or module ( ) is used to control a speech encoder ( ) and a speech decoder ( ), as well as a background noise encoder ( ) and a background noise decoder ( ) in order to perform source-controlled reduction of the mean transmission rate. After segmenting a speech signal, a wavelet transformation is computed for each frame, from which a set of parameters is determined, from which in turn a set of binary decision variables is calculated with the help of fixed thresholds in an arithmetic circuit ( ). The decision variables control a decision logic circuit ( ), whose result, after time smoothing in a time smoothing circuit ( ), provides the statement “speech present/no speech” for each frame. The circuit itself includes segmenting circuit ( ), a wavelet transformation circuit ( ), an arithmetic circuit for the energy values ( ), a pause detection circuit ( ), a circuit for detecting stationary states ( ), a first and a second background detector ( ), a downstream decision logic ( ), and the circuit ( ) for time smoothing, which provides the desired statement at its output ( ).