Systems and methods for adaptive noise cancellation by biasing anti-noise level

摘要

A processing circuit may comprise an adaptive filter having a response generating an anti-noise signal from a reference microphone signal, a secondary path estimate filter modeling an electro-acoustic path of a source audio signal, a biasing portion that generates a scaled anti-noise signal by applying a scaling factor and the response of the secondary path estimate filter to the anti-noise signal, and a coefficient control block that shapes the response of the adaptive filter in conformity with the reference microphone signal and a modified playback corrected error signal by adapting the response of the adaptive filter to minimize ambient audio sounds in the error microphone signal, wherein the playback corrected error is based on a difference between the error microphone signal and the source audio signal and the modified playback corrected error signal is based on a difference between the playback corrected error signal and the scaled anti-noise signal.

主权项

1. A personal audio device comprising:
a personal audio device housing; a transducer coupled to the personal audio device housing for reproducing an audio signal including both a source audio signal for playback to a listener and an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the transducer; a reference microphone coupled to the personal audio device housing for providing a reference microphone signal indicative of the ambient audio sounds; an error microphone coupled to the personal audio device housing in proximity to the transducer for providing an error microphone signal indicative of the acoustic output of the transducer and the ambient audio sounds at the transducer; and a processing circuit comprising:
an adaptive filter having a response that generates an anti-noise signal from the reference microphone signal;a secondary path estimate filter configured to model an electro-acoustic path of the source audio signal and have a response that generates a secondary path estimate from the source audio signal;a biasing portion that generates a scaled anti-noise signal by applying a scaling factor and the response of the secondary path estimate filter to the anti-noise signal; anda coefficient control block that shapes the response of the adaptive filter in conformity with the reference microphone signal and a modified playback corrected error signal by adapting the response of the adaptive filter to minimize the ambient audio sounds in the error microphone signal, wherein a playback corrected error signal is based on a difference between the error microphone signal and the secondary path estimate and the modified playback corrected error signal is based on a difference between the playback corrected error signal and the scaled anti-noise signal.