Time-varying allpass filters using spectral-shaped noise for signal decorrelation in stereophonic acoustic echo cancellation

A signal decorrelation technique is presented which aims at alleviating the non-uniqueness problem in stereophonic acoustic echo cancellation (SAEC) whilst minimising the degradation of stereo signal perception. The proposed technique is based on higher-order time-varying allpass filters (HO-TV-APFs) utilising spectral-shaped noise, together with the interpolation method. Two approaches for spectral-shaped random noises are introduced, while the test results on speech signals indicate improved performance in both objective and subjective manners.