| 摘要 |
<p>To achieve an improved convergence behaviour for, e.g., echo cancellation there is provided a digital adaptive filter comprising a filter coefficient update means (52; 78) to successively update filter coefficience in accordance with an input signal (x), an estimated power (PI) of the input signal, and an error signal between the input signal filtered in the digital adaptive filter and the input signal propagated along an external path (16) being modelled by the digital adaptive filter. Here, an input signal power estimation means (50, 84-92) is adapted to perform recursive smoothing for an increasing input power and a decreasing input power in an asymmetric fashion with different smoothing factors. In case the estimation is carried out in the frequency domain the step size for the update of filter coefficients may be adapted frequency band selectively.</p> |
