An improved active noise control system without secondary path model

Most active noise control algorithms require the identification of the secondary path model. This will give rise to increased complexity and other potential problems in the real system. In this paper, we proposed an improved ANC algorithm requiring no secondary path model by introducing a phase compensating mechanism based on the strict positive real (SPR)property of the filtered-x LMS algorithm. Compared with the existing methods, our algorithm can automatically find the right phase compensating amount of secondary path and will always converge regardless of the frequency of reference signal.