| 摘要 |
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 (5) is used to control a speech encoder (9) and a speech decoder (22), as well as a background noise encoder (10) and a background noise decoder (23) 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 (32). The decision variables control a decision logic circuit (42), whose result, after time smoothing in a time smoothing circuit (44), provides the statement "speech present/no speech" for each frame. The circuit itself includes segmenting circuit (28), a wavelet transformation circuit (30), an arithmetic circuit for the energy values (32), a pause detection circuit (34), a circuit for detecting stationary states (35), a first and a second background detector (36, 37), a downstream decision logic (42), and the circuit (44) for time smoothing, which provides the desired statement at its output (45).
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