Patent ID: 8311842

Claim:
A method for expanding a bandwidth of an input narrowband voice signal, the method comprising the steps of: analyzing the narrowband voice signal separately for each frame, and calculating a Degree of Voicing (DV) included in the narrowband voice signal and a Degree of Stationary (DS) concerning time-varying characteristic for the narrowband voice signal depending on the analysis; calculating a Degree of Difficulty of Bandwidth Expansion (DDBWE) of the narrowband voice signal by using a product of DV, a product of DS and a α which is a weighting parameter for adjusting a ratio of DV and DS; and controlling bandwidth expansion adaptively according to DDBWE, wherein DDBWE is defined as a value obtained by subtracting from ‘1’, a sum of the product of DV and α and the product of DS and a value obtained by subtracting α from 1, where α has a value between ‘0’ and ‘1’.