Hybrid Active Noise Control System in Duct and Implementat ion

In active noise control(ANC),the FXLMS algorithm has been widely used f or its simplicity and low computational load.In feedforward ANC systems to funct ion efficiently,the primary signal must be highly correlated with the reference signal,However,in complex practical application this condition may not be met;in feedback ANC systems,the cancellation effect does not depend on the noise field coherence,but it is only efficient in narrowband,and may be unstable on some fr equencies.Hybrid ANC combine the feedforward and feedback ANC,it is more efficie nt than either the simple feedforward ANC or adaptive feedback ANC system alone. In this paper a realtime ANC system based TMS320C30 controller is proposed,and several realtime ANC experiments were done on a fanduct system,the results show that hybrid FXLMS ANC can gain more ideal effect.