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Abstract

In this paper, an improved adaptive noise cancellation approach is proposed for voice communication signals. The method is based on using noise dependent affine projection algorithm ND-APA. A conditionally variable projection order affine projection algorithm APA is developed and tested. The order of the algorithm is changed according to the change in the characteristics of the noise. The eigenvalue spread of the noise autocorrelation matrix is used as a criterion for projection order change. The order of the algorithm is made to vary from 4 to 32 according the value of the spread which changes from less than 5 for white noise to more than 15 for colored noise. The proposed method showed a superior performance as compared to the classical APA, LMS and RLS noise cancelation methods. The technique presented here can be very useful in removing environmental noise in fixed and mobile communication.

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