| 摘要 |
Method and devices for generating background noise in a telecommunication system comprising the steps of dividing the input signal into frames, computing the coefficients for an inverse filter A(z) for the present frame, wherein A(z) is the z-transform of the inverse filter, and computing auto correlation functions from original candidate vectors and an output signal after the inverse filter and applying a distance measure between transformed candidate vectors and a transformed output signal from an inverse filter. A best candidate vector is selected by means of a distance measure in the ACF domain in order to provide a good match in the autocorrelation domain. The method improves the perceived quality of regenerated background noise, for instance such as a reduction of swirling and fluttering noise caused by a limited set of spectral shapes caused by quantization of the signal spectrum. The cost for said improvement in extra bits sent is very moderate. |
