Patent ID: 9224382
Filing Date: 2015-12-29
Classification: G10K,H03G,H04R

Abstract:
1. A method of generating a noise cancellation signal, the method comprising: generating an ambient noise signal, representing ambient noise; generating a noise cancellation signal, by applying the ambient noise signal to a feedforward filter, wherein the feedforward filter comprises a high-pass filter having an adjustable cut-off frequency, and by applying a controllable gain; applying the noise cancellation signal to a loudspeaker, to generate a sound to at least partially cancel the ambient noise; and generating an error signal, representing unwanted sound in the region of the loudspeaker, wherein the method further comprises: comparing a phase of the ambient noise signal to a phase of the error signal, and controlling said gain on the basis of a result of said comparison, and taking account of a phase shift introduced by said high-pass filter when performing said comparison.