Abstract: To enhance performance of traditional filters, an improved filter is proposed using orthonormal basis functions. The mathematical orthonormal function is introduced into the structure of filter. Prior information of the system is obtained by mapping the system model to orthonormal basis function. This is different from the present filters. Comparison between traditional filters and the orthogonal filter is made. Computation formulations of the new algorithm are given. Results of numerical simulation and the practical application to aircraft cabin noise rejection indicate that the new filter algorithm has fast convergence and high stability with small number of tap-weight.

Key words: adaptive filtering, orthonormal functions, filter structure, filtering algorithm, aircraft cabin