Acoustic echo cancellation using subband technique for teleconferencing applications

In acoustic echo cancellation, the conventional adaptive FIR filter can have many taps, resulting in a large computational complexity and slow convergence of the algorithm. Multi-rate techniques can be used to overcome these disadvantages by adapting several shorter filters in subbands at a reduced rate. However, the down sampling process introduces aliased version of the original signals, especially when signals are critically down sampled. In this paper, the nonoverlapping filter banks with decimated auxiliary subbands are employed to alleviate distortion due to aliasing and spectral gaps, while a low computational load is maintained.