Patent ID: 11961503
Assignee: HARMAN BECKER AUTOMOTIVE SYSTEMS GMBH
Field: Other consumer goods (Other fields)
Classification: CPC G | IPC A  G

Claim 6:
7. An automatic noise control method comprising:
evaluating an amplitude of an acceleration acting on an acceleration sensor and generating a reference signal representative of the amplitude of the acceleration, the acceleration being representative of unwanted noise sound generated by a noise source;
filtering the reference signal with a noise control transfer function to generate an anti-noise signal;
converting with a loudspeaker the anti-noise signal into anti-noise sound;
receiving with a microphone the noise sound after being transferred via a primary path according to a primary path transfer function from the noise source to the microphone and the anti-noise sound after being transferred via a secondary path according to a secondary path transfer function from the loudspeaker to the microphone, and converting with the microphone a sum of the received noise sound and the received anti-noise sound into an error signal;
controlling the noise control transfer function based on the error signal from the microphone and the filtered reference signal or the unfiltered reference signal from the acceleration sensor so that the anti-noise sound after being transferred via the secondary path is the inverse of the noise sound after being transferred via the primary path;
applying via the filter controller to the noise control transfer function of the noise control filter a leakage based on the error signal from the microphone and the filtered reference signal or the unfiltered reference signal from the acceleration sensor;
filtering the filtered reference signal or the unfiltered reference signal from the acceleration sensor with a transfer function that is identical with the noise control transfer function of the noise control filter to generate an additional anti-noise signal;
subtracting the additional anti-noise signal provided by the additional noise control filter from the error signal provided by the microphone to generate an estimated disturbing signal, the estimated disturbing signal being an estimation of a disturbing sound, which is the noise sound after being transferred via the primary path from the noise source to the microphone; and
comparing the error signal with the estimated disturbing signal and controlling the filter controller to apply the leakage dependent on the comparison.