CPC G10K 11/17817 (2018.01) [G10K 11/17854 (2018.01); G10K 11/17857 (2018.01); G10L 21/0208 (2013.01); G10L 25/84 (2013.01); H04R 1/406 (2013.01); H04R 3/005 (2013.01); G10L 2021/02082 (2013.01); H04R 2499/13 (2013.01)] | 14 Claims |
1. An active noise control system for reducing noise, the active noise control system comprising:
a first area microphone that is a microphone disposed in a first area;
a second area speaker that is a speaker disposed in a second area;
a second area microphone that is a microphone disposed in the second area;
an echo cancellation adaptive filter configured to receive an output of the first area microphone as an input;
an echo cancellation adder configured to add an output of the second area microphone and an output of the echo cancellation adaptive filter;
a secondary path reproduction filter configured to receive a noise signal representing noise and to share a filter coefficient with the echo cancellation adaptive filter;
a noise cancellation adaptive filter configured to receive the noise signal as an input; and
a noise cancellation adder configured to add the output of the first area microphone and an output of the noise cancellation adaptive filter and to output a resulting sum to the second area speaker;
wherein the echo cancellation adaptive filter is configured to update a filter coefficient such that an output of the echo cancellation adder is regarded as an error and the error is minimized; and
wherein the noise cancellation adaptive filter is configured to update the filter coefficient by a Filtered-X LMS algorithm in which the output of the second area microphone is regarded as an error and an output of the secondary path reproduction filter is regarded as a reference signal.
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