Adaptive active noise control schemes in time-domain and transform-domains

A general structure of adaptive active noise control systems is investigated to propose stability-assured adaptive algorithms to update parameters of an adaptive feedforward controller. In order to deal with a general case where all of the sound transmission channel dynamics are uncertainly changeable, which cannot be solved by conventional approaches, a new fully adaptive algorithm is also presented on a basis of robust stabilization by a fixed feedback controller and the strictly positive real property of a newly given error system. The proposed adaptive algorithms can be implemented by not only the time-domain approaches, but also a frequency-domain approach using an adaptive frequency sampling filter and a wavelet transform domain approach using an adaptive wavelet packet filter bank. Comparison of the three proposed approaches is given through numerical simulations and experiments.