Comparison of Virtual Sensing Techniques for Broadband Feedforward Active Noise Control

摘要

Active noise control (ANC) is one of noise reduction techniques based on the acoustic wave superposition. When an anti-noise wave with the same amplitude and opposite phase of the noise wave is generated from the secondary source, the sound pressure level of the unwanted acoustic noise can be reduced at the desired location, where an error microphone is placed to monitor the error signal and make the whole system a closed-loop control problem. The virtual sensing (VS) techniques are developed for the situation when the error microphone cannot be placed at the desired location due to the application constraint or physical limitation. In this paper, we compare two virtual sensing techniques for reducing the broadband noise. They are the remote microphone (RM) method and the auxiliary filter based virtual sensing (AF-VS) method. The former estimates the transfer function from an error microphone location to the desired location, which has been validated to reduce the narrowband noise effectively. The latter preserves the information about the optimal noise control filter that can achieve the maximum noise reduction at the desired location. The experiment results demonstrate that the AF - VS method has more superior advantages for broadband noise reduction at the desired location than the RM method and has no limitations on the geometrical relationship between the error microphone location and the desired location