ANC algorithms that do not require identifying the secondary path

Most available control algorithms for active noise control (ANC) require identification of the secondary path. This estimation not only increases the control system complexity, but it can add to the residual noise power and even cause the adaptive system to diverge when the identification is not sufficiently close to the real system. We use a geometrical analysis of the filtered-x LMS algorithm to introduce a new ANC algorithm for a single frequency and narrowband noise where no identification of the secondary path is required. We then extend our new ANC algorithm without secondary path identification to the active control of broadband noise through the use of a sub-band ANC implementation. When compared to other available control algorithms requiring no secondary path identification, our method possesses a simple structure, good performance, and a reasonable convergence rate. Simulation results confirm the effectiveness of our proposed algorithms.