Patent ID: 9659558
Date: 2017-05-23
CPC Classifications: G10K

Claim:
1. An apparatus for active noise cancellation, said apparatus comprising: a reference microphone configured to produce a reference microphone signal in response to a first acoustic signal; a first analog-to-digital converter (ADC) that is coupled to the reference microphone and configured to produce an output signal that is based on the reference microphone signal; an error microphone configured to produce an error microphone signal in response to a second acoustic signal; a second ADC that is coupled to the error microphone and configured to produce an output signal that is based on the error microphone signal; a processor (A) having a first input coupled to the first ADC, a second input coupled to the second ADC, and a third input configured to receive a desired sound signal at a first sampling rate and (B) configured to provide updates based on the first, second, and third inputs; and a digital filter that is coupled to the first ADC, arranged to receive the updates from the processor, and configured to filter a reference noise signal that is based on the output signal of the first ADC, at a second sampling rate that is higher than the first sampling rate, to produce an anti-noise signal.