Patent ID: 9318094
Filing Date: 2016-04-19
CPC Classification: G10K,H04R

Claim Text:
1. A personal audio device, comprising: a personal audio device housing; a transducer mounted on the housing for reproducing an audio signal including both source audio 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 mounted on the housing for providing a reference microphone signal indicative of the ambient audio sounds; an error microphone mounted on the 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; a processing circuit that implements an adaptive filter having a response that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener, wherein the processing circuit implements a coefficient control block that shapes the response of the adaptive filter in conformity with the error microphone signal and the reference microphone signal by adapting the response of the adaptive filter to minimize the ambient audio sounds at the error microphone, wherein a first sample rate of the adaptive filter is substantially higher than a second sample rate at which the coefficient control block operates, wherein the source audio has a sample rate equal to or less than the second sample rate; an interpolator included in the processing circuit that converts the source audio to the first sample rate; and a combiner included in the processing circuit that combines the anti-noise signal and an output of the interpolator to generate the audio signal at the first sample rate.