Patent ID: 11942068
Assignee: AIROHA TECHNOLOGY CORP.
Field: Other consumer goods (Other fields)
Classification: CPC G | IPC G

Claim 0:
1. An adaptive active noise control (ANC) system comprising:
an ANC circuit, arranged to generate an anti-noise signal for noise reduction, wherein the ANC circuit comprises at least one adaptive filter; and
a control circuit, arranged to receive a first input signal derived from a reference signal output by a reference microphone that picks up ambient noise, receive a second input signal derived from an error signal output by an error microphone that picks up remnant noise resulting from the noise reduction, and perform a transfer function variation detection based on the first input signal and the second input signal to control the at least one adaptive filter, wherein the transfer function variation detection is arranged to detect transfer function variation of a path between the first input signal and the second input signal, and the control circuit comprises:
a detection circuit, arranged to deal with the transfer function variation detection, wherein the detection circuit comprises:
a transfer function estimation circuit, arranged to estimate a previous transfer function of the path between the first input signal and the second input signal and a current transfer function of the path between the first input signal and the second input signal;
a path change degree evaluation circuit, arranged to determine a path change degree value according to difference between the previous transfer function and the current transfer function; and
a comparison circuit, arranged to compare the path change degree value with a pre-defined threshold to generate a comparison result, set a flag signal according the comparison result, and output the flag signal to the at least one adaptive filter;

wherein the at least one adaptive filter is controlled by the flag signal.