Abstract: A noise source emits an acoustic noise wave with a noise frequency corresponding to an attribute of a control-status signal associated with the noise source. A method to reduce the noise comprises generating, based on the noise frequency corresponding to the attribute, an anti-noise signal having the noise frequency. The method further comprises phase-shifting the anti-noise signal to output a phase-shifted anti-noise signal that can be used to generate a noise-cancelling acoustic wave. The method can include aligning the first anti-noise signal to be in-phase with the acoustic noise wave. An anti-noise apparatus to implement the method includes an anti-noise generator, to generate the anti-noise signal, and a phase shifter to generate and output the phase-shifted anti-noise signal. The anti-noise apparatus can include a phase detector and phase alignment element to align the anti-noise signal to be in-phase with the acoustic noise wave.

Abstract: A noise source emits an acoustic noise wave with a noise frequency corresponding to an attribute of a control-status signal associated with the noise source. A method to reduce the noise comprises generating, based on the noise frequency corresponding to the attribute, an anti-noise signal having the noise frequency. The method further comprises phase-shifting the anti-noise signal to output a phase-shifted anti-noise signal that can be used to generate a noise-cancelling acoustic wave. The method can include aligning the first anti-noise signal to be in-phase with the acoustic noise wave. An anti-noise apparatus to implement the method includes an anti-noise generator, to generate the anti-noise signal, and a phase shifter to generate and output the phase-shifted anti-noise signal. The anti-noise apparatus can include a phase detector and phase alignment element to align the anti-noise signal to be in-phase with the acoustic noise wave.