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An acoustic echo canceller using lapped orthogonal transform

In the teleconference system or the hands-free telephone, the speech broadcasted from the loudspeaker can be transformed back to the talker as a far-end talker-echo. The far-end talker-echo can be eliminated by an acoustic echo canceller. An acoustic echo canceller based on the lapped orthogonal transform (LOT) using discrete Walsh-Hadamard transform (DWHT) as the building block for the fast algorithm is presented. The new structure can provide better ERLE and tracking capability than the structure using the LOT presented by Malver (1992). The computation complexity of the new structure is much lower than the orthogonal transform LMS structure.