On Adaptive Feedback Active Noise Control Systems With Online Adaptation of Secondary Path Estimation Filter

This paper focuses on identifying the secondary path (SP) in feedback active noise control (FBANC) systems during online operation. In FBANC, it's not feasible to install a reference microphone for capturing the reference signal needed for the (adaptive) active noise control (ANC) filter. Consequently, an appropriate reference signal is required to be electronically generated, necessitating an accurate estimation of the SP. The accuracy of SP estimation (SPE) directly impacts the stability and noise reduction capabilities of ANC systems. Building upon prior work that utilized two adaptive filters; one for ANC and another for SPE; this paper presents a method with a similar structure. The key idea in this paper is to tailor a generalized sigmoid function for developing a variable step-size (VSS)-based adaptive algorithm for (adaptive) ANC filter. The proposed method exhibits improved noise reduction performance as well as good SPE performance, as evidenced by the detailed numerical results provided in the paper.