ダクト両端部の同時アクティブ消音

Abstract

This paper presents a method for simultaneous active noise control of both ends of a duct. So far many papers on active noise control have been published. Most of them，however，treat the problem of noise reduction in one side of the duct. This paper discusses a method for simultaneous active noise control of both ends of a duct using single microphone placed near to the noise source and two set s of control speakers placed near to the both ends of the duct. First， based on the expression of the sound in the duct obtained as a sum of sound waves propagated from the noise source， control speakers and reflections from the ends， a control law for noise ecancelation at the both ends is derived. Then， the control law is approximated to implement real time control in the form of the IIR digital filter. Finally， experiment is conductedto confirm the validity of the presented active noise control method.