SINGLE CHANNEL SYSTEM FOR ADAPTIVE POWER MINIMIZATION

摘要

Global active noise reduction in the low frequency band can be achieved by minimization of sound power. The total power radiated by a pair of sound sources is minimal, if they are in or out of phase and the power output of one source is exactly zero. This phenomenon is used by a single channel system consisting of one accelerometer, one pressure sensor and a loudspeaker to minimize the radiated power of a tonal noise source. The acceleration of its surface is applied as reference signal for an adaptive feed forward algorithm. The intensity based control method as well as the application on piston sources are discussed. The results show that the radiated sound power can be reduced by more than 10 dB.