Wireless active noise control results

Abstract

Active Noise Control (ANC) is used in controlling low frequency noise where passive control is ineffective. Most (ANC) systems use physical cables to connect various parts of the system for operation. This can be bulky and prohibitive especially for systems with many channels. This paper presents the results obtained from a study of wireless ANC in which two transceivers are used in an existing ANC system that uses the FX-LMS adaptive feedforward algorithm. An experimental setup of a single-channel ANC system in a small enclosed room was utilized, where a single frequency noise was controlled using the wireless system. It was found that the wireless system gave comparable results to the wired system and that the time delay error in the transceivers affects both the attenuation of noise and convergence time of the wireless system. The effect of an error microphone moving at a constant velocity to simulate a person moving inside the room was also studied. The results show that wireless ANC is still possible for speeds up to 2.5 m/s. However, the cabled system performs slightly better than the wireless one. This may be attributed to the error present during wireless transmission of the signals during the modelling and control stages.