Abstract:

The application of active noise control has been extended from single noise source, one-dimensional acoustical fields to complicated multiple noise source, three-dimensional acoustical fields. The application to a multiple noise source environment usually requires multiple reference sensors to generate a complete vector of reference signals. A widely adopted control configuration feeds each reference signal into a different control filter. This approach suffers from the problem of ill-conditioning when the reference signals are correlated. The problem of ill-conditioning results in slow convergence rate and high sensitivity to measurement error especially when the FXLMS algorithm is applied. A practical method is presented to pre-process the reference signals based on the Wiener filter theory and Gram-Schmidt orthogonalization which overcomes these problems. Simulations and experiments have been conducted to verify the issues associ-ated with multiple reference ANC when the signals are correlated. The results presented are consistent with the theoretical analysis. [Work supported by ONR.]