A Computation Saving Echo Canceller For A Wide Band Audio Signal

Abstract: A wide band echo canceller (EC2) comprising:  means (SP1) for splitting a signal (TXi) transmitted from a near end terminal to a far end terminal into a sub sampled signal (TH) corresponding to a higher frequency sub band of the signal (TXi) transmitted to the far end terminal and a sub sampled signal (TL) corresponding to a lower frequency sub band of the signal (TXi) transmitted to the far end terminal  means (SP2) for splitting a signal (RXi) received from a far end terminal into a sub sampled signal (RH) corresponding to a higher frequency sub band of the signal (RXi) received from the far end terminal and a sub sampled signal (RL) corresponding to a lower frequency sub band of the signal (RXi) received from the far end terminal  a first adaptive filter (AL) for filtering the sub sampled signal (TL) corresponding to the lower frequency sub band  a second adaptive filter (AH) for filtering the sub sampled signal (TH) corresponding to the higher frequency sub band  subtracting means (SL SH) controlling the adaptive filters (AL AH)  means (MX) for mixing two process corrected signals (CRL  CRH ) and up sampling the resulting signal  control means (CTR STL STH) that control the adaptation of the first adaptive filter (AL) and the adaptation of the second adaptive filter (HL) so that these two adaptations are never simultaneous.

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