Automatic tap-length adjustment of adaptive filter for feedback attenuation in hearing aids. (15th January 2020)

• Record Type: Journal Article
• Authors: Kar, Asutosh; Anand, Ankita; Swamy, M.N.S.
• Is Part Of: Applied acoustics. Volume 158(2020)
• Publication Date: 2020-01-15
• Subjects: Feedback cancellation -- Adaptive filters -- Tap length -- Convergence -- Mean square error; Acoustical engineering -- Periodicals; Periodicals; 620.2
• DOI: 10.1016/j.apacoust.2019.107043
• Languages: English
• ISSNs: 0003-682X

Abstract

Abstract: In this paper, a tap-length-adaptation algorithm is proposed for adaptive feedback cancellation (AFC) in the adaptive filter used in digital hearing aids. The existing state-of-the-art feedback cancellers use a fixed-length adaptive filter, which might over-model or under-model the feedback path. To overcome the issue of selecting a fixed arbitrary tap-length value, a unique automatic tap-length-variation algorithm is proposed for the adaptive filter. A key tap-length-update parameter, which ensures a balance between the deviation between steady-state and optimal values of the tap length and influences the convergence speed of the tap-length adaptation, has also been made adaptive for efficient feedback path estimation. A detailed mathematical performance-analysis of the proposed algorithm at steady state is performed. Computer simulations verify that the derived expressions predict the proposed algorithm's improved performance over that of the existing algorithms.