Patent ID: 9325821
Filing Date: 2016-04-26
CPC Classification: G10K,H04M,H04R

Claim Text:
1. A wireless telephone, comprising: a housing; a transducer mounted on the housing for reproducing an audio signal including combined downlink audio and sidetone 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 near-speech microphone mounted on the housing for providing a near-speech microphone signal indicative of speech of the listener and the ambient audio sounds; and a processing circuit that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener in conformity with an error signal and the reference microphone signal, wherein the processing circuit generates sidetone from a portion of the near-speech microphone signal, wherein the processing circuit combines the downlink audio with the sidetone, wherein the processing circuit implements a secondary path adaptive filter having a secondary path response that shapes the combined downlink audio and sidetone and a combiner that removes an output of the secondary path adaptive filter from the error microphone signal to provide the error signal, wherein the secondary path adaptive filter is controlled by a secondary path coefficient controller that compares the error signal with the downlink audio and adapts to minimize components of the downlink audio present in the error signal but does not minimize components of the sidetone, so that the anti-noise signal is not affected by the ambient audio sounds present in the near-speech microphone signal.