A study on an active noise control system using an adaptive exponential filter

Active noise control systems that have been studied previously require a replica of the cancellation path to obtain the updating weight values, because the signals for the operation cannot be observed. In this paper we propose a structure and an adaptive algorithm for the active noise control system using an adaptive exponential filter that does not require any replica. The adaptive algorithm is based on the steepest descent method that can be easily realized and the updating weight value of the adaptive exponential filter is the correlation of the observable output signal of the adaptive system and the estimation error. The other adaptive filters are composed of the linear transversal system. It is proven that the transfer function after converging completely corresponds to the transfer function of the noise and the cancellation path under a certain condition. Finally, the convergence performance of the estimation accuracy and the tracking performance with respect to rapid changes of the noise and the cancellation paths are verified by computer simulation. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(1): 53–59, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10256