Patents by Inventor Jeffrey Alderson

Jeffrey Alderson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9324311
    Abstract: An adaptive noise canceling (ANC) circuit adaptively generates an anti-noise signal from that is injected into the speaker or other transducer output to cause cancellation of ambient audio sounds. At least one microphone provides an error signal indicative of the noise cancellation at the transducer, and the coefficients of the adaptive filter are adapted to minimize the error signal. In order to prevent improper adaptation or instabilities in one or both of the adaptive filters, spikes are detected in the error signal by comparing the error signal to a threshold ambient noise average. Therefore, if the magnitude of the coefficient error is greater than a threshold value for an update, the update is skipped. Alternatively the step size of the updates may be reduced.
    Type: Grant
    Filed: March 14, 2014
    Date of Patent: April 26, 2016
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Ali Abdollahzadeh Milani, Jeffrey Alderson, Gautham Devendra Kamath, Yang Lu
  • Patent number: 9318094
    Abstract: A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal that measures the ambient audio and an error microphone signal that measures the output of an output transducer plus any ambient audio at that location and injects the anti-noise signal at the transducer output to cause cancellation of ambient audio sounds. A processing circuit uses the reference and error microphone to generate the anti-noise signal, which can be generated by an adaptive filter operating at a multiple of the ANC coefficient update rate. Downlink audio can be combined with the high data rate anti-noise signal by interpolation. High-pass filters in the control paths reduce DC offset in the ANC circuits, and ANC coefficient adaptation can be halted when downlink audio is not detected.
    Type: Grant
    Filed: March 7, 2012
    Date of Patent: April 19, 2016
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Jon D. Hendrix, Gautham Devendra Kamath, Nitin Kwatra, Ali Abdollahzadeh Milani, Jeffrey Alderson
  • Patent number: 9318090
    Abstract: An adaptive noise canceling (ANC) circuit adaptively generates an anti-noise signal from a reference microphone signal that is injected into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone proximate the speaker provides an error signal. A secondary path estimating adaptive filter estimates the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Tones in the source audio, such as remote ringtones, present in downlink audio during initiation of a telephone call, are detected by a tone detector using accumulated tone persistence and non-silence hangover counting, and adaptation of the secondary path estimating adaptive filter is halted to prevent adapting to the tones. Adaptation of the adaptive filters is then sequenced so any disruption of the secondary path adaptive filter response is removed before allowing the anti-noise generating filter to adapt.
    Type: Grant
    Filed: December 28, 2012
    Date of Patent: April 19, 2016
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Dayong Zhou, Yang Lu, Jon D. Hendrix, Jeffrey Alderson, Antonio John Miller, Chin Yong, Gautham Devendra Kamath
  • Patent number: 9319781
    Abstract: A personal audio device, such as a wireless telephone, includes noise canceling circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone may also be provided proximate the speaker to measure the output of the transducer in order to control the adaptation of the anti-noise signal and to estimate an electro-acoustical path from the noise canceling circuit through the transducer. A processing circuit that performs the adaptive noise canceling (ANC) function also detects frequency-dependent characteristics in and/or direction of the ambient sounds and alters adaptation of the noise canceling circuit in response to the detection.
    Type: Grant
    Filed: March 4, 2013
    Date of Patent: April 19, 2016
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Jeffrey Alderson, Jon D. Hendrix, Dayong Zhou
  • Publication number: 20160063988
    Abstract: A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate the speaker to measure the ambient sounds and transducer output near the transducer, thus providing an indication of the effectiveness of the noise canceling. A processing circuit uses the reference and/or error microphone, optionally along with a microphone provided for capturing near-end speech, to determine whether the ANC circuit is incorrectly adapting or may incorrectly adapt to the instant acoustic environment and/or whether the anti-noise signal may be incorrect and/or disruptive and then take action in the processing circuit to prevent or remedy such conditions.
    Type: Application
    Filed: August 31, 2015
    Publication date: March 3, 2016
    Inventors: Jon D. Hendrix, Ali Abdollahzadeh Milani, Nitin Kwatra, Dayong Zhou, Yang Lu, Jeffrey Alderson
  • Patent number: 9230532
    Abstract: A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from an output of a microphone that measures ambient audio. The anti-noise signal is combined with source audio to provide an output for a speaker. The anti-noise signal causes cancellation of ambient audio sounds that appear at the microphone. A processing circuit estimates a level of background noise from the microphone output and sets a power conservation mode of the personal audio device in response to detecting that the background noise level is lower than a predetermined threshold.
    Type: Grant
    Filed: March 12, 2013
    Date of Patent: January 5, 2016
    Assignee: Cirrus, Logic Inc.
    Inventors: Yang Lu, Dayong Zhou, Jon D. Hendrix, Jeffrey Alderson
  • Patent number: 9226068
    Abstract: A personal audio device including earspeakers, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each earspeaker from at least one microphone signal that measures the ambient audio, and the anti-noise signals are combined with source audio to provide outputs for the earspeakers. The anti-noise signals cause cancellation of ambient audio sounds at the respective earspeakers. A processing circuit uses the microphone signal(s) to generate the anti-noise signals, which can be generated by adaptive filters. The processing circuit controls adaptation of the adaptive filters such that when the processing circuit detects that either of the earspeakers are off-ear, a gain applied to the anti-noise signals is reduced.
    Type: Grant
    Filed: March 12, 2015
    Date of Patent: December 29, 2015
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Jon D. Hendrix, Jeffrey Alderson
  • Patent number: 9208771
    Abstract: An adaptive noise canceller adapts a secondary path modeling response using ambient noise, rather than using another noise source or source audio as a training source. Anti-noise generated from a reference microphone signal using a first adaptive filter is used as the training signal for training the secondary path response. Ambient noise at the error microphone is removed from an error microphone signal, so that only anti-noise remains. A primary path modeling adaptive filter is used to modify the reference microphone signal to generate a source of ambient noise that is correlated with the ambient noise present at the error microphone, which is then subtracted from the error microphone signal to generate the error signal. The primary path modeling adaptive filter is previously adapted by minimizing components of the error microphone signal appearing in an output of the primary path adaptive filter while the anti-noise signal is muted.
    Type: Grant
    Filed: October 25, 2013
    Date of Patent: December 8, 2015
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Dayong Zhou, Yang Lu, Jon D. Hendrix, Jeffrey Alderson
  • Publication number: 20150269926
    Abstract: A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate to the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. A level of the source audio with respect to the ambient audio is determined to determine whether the system may generate erroneous anti-noise and/or become unstable.
    Type: Application
    Filed: June 9, 2015
    Publication date: September 24, 2015
    Inventors: Jeffrey Alderson, Jon D. Hendrix, Dayong Zhou, Antonio John Miller, Chin Yong, Gautham Devendra Kamath
  • Patent number: 9142205
    Abstract: A personal audio device, such as a headphone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal that measures the ambient audio, and the anti-noise signal is combined with source audio to provide an output for a speaker. The anti-noise signal causes cancellation of ambient audio sounds that appear at the reference microphone. A processing circuit uses the reference microphone to generate the anti-noise signal, which can be generated by an adaptive filter. The processing circuit also models an acoustic leakage path from the transducer to the reference microphone and removes elements of the source audio appearing at the reference microphone signal due to the acoustic output of the speaker. Another adaptive filter can be used to model the acoustic leakage path.
    Type: Grant
    Filed: December 3, 2012
    Date of Patent: September 22, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: Jeffrey Alderson, Jon D. Hendrix
  • Patent number: 9142207
    Abstract: A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate the speaker to measure the ambient sounds and transducer output near the transducer, thus providing an indication of the effectiveness of the noise canceling. A processing circuit uses the reference and/or error microphone, optionally along with a microphone provided for capturing near-end speech, to determine whether the ANC circuit is incorrectly adapting or may incorrectly adapt to the instant acoustic environment and/or whether the anti-noise signal may be incorrect and/or disruptive and then take action in the processing circuit to prevent or remedy such conditions.
    Type: Grant
    Filed: December 1, 2011
    Date of Patent: September 22, 2015
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Jon D. Hendrix, Ali Abdollahzadeh Milani, Nitin Kwatra, Dayong Zhou, Yang Lu, Jeffrey Alderson
  • Patent number: 9123321
    Abstract: A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate to the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Adaptation of adaptive filters is sequenced so that update of their coefficients does not cause instability or error in the update. A level of the source audio with respect to the ambient audio can be determined to determine whether the system may generate erroneous anti-noise and/or become unstable.
    Type: Grant
    Filed: December 27, 2012
    Date of Patent: September 1, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: Jeffrey Alderson, Jon D. Hendrix, Dayong Zhou, Antonio John Miller, Chin Yong, Gautham Devendra Kamath
  • Patent number: 9106989
    Abstract: Techniques for estimating adaptive noise canceling (ANC) performance in a personal audio device, such as a wireless telephone, provide robustness of operation by triggering corrective action when ANC performance is low, and/or by saving a state of the ANC system when ANC performance is high. An anti-noise signal is generated from a reference microphone signal and is provided to an output transducer along with program audio. A measure of ANC gain is determined by computing a ratio of a first indication of magnitude of an error microphone signal that provides a measure of the ambient sounds and program audio heard by the listener including the effects of the anti-noise, to a second indication of magnitude of the error microphone signal without the effects of the anti-noise. The ratio can be determined for different frequency bands in order to determine whether particular adaptive filters are trained properly.
    Type: Grant
    Filed: September 17, 2013
    Date of Patent: August 11, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: Ning Li, Antonio John Miller, Jon D. Hendrix, Jie Su, Jeffrey Alderson, Ali Abdollahzadeh Milani
  • Patent number: 9094744
    Abstract: A close talk detection method and system is provided for active noise cancellation system on a cellular telephone or the like, based on two properly located microphones. Given the location of the microphones and the way people use the phone, the power ratio (difference) at the two microphones implies the location of the speaker within a given range. The improved close-talk detector is not affected by power levels or SNR of non-close-talk ambient disturbances. Power levels of both a voice and a reference microphone are measured and the ratio r of these power levels is determined. If the ratio r is greater than a predetermined threshold (e.g., 7 dB), then close talk is occurring. If the ratio r is less than the predetermined threshold, then the signal is determined to be loud ambient noise or some other non-close-talking signal and noise cancellation processing is not affected.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: July 28, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: Yang Lu, Dayong Zhou, Jon D. Hendrix, Jeffrey Alderson
  • Patent number: 9082387
    Abstract: A personal audio device, such as a wireless telephone, generates an anti-noise signal from an error microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. The error microphone is also provided proximate the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Noise bursts are injected intermittently and the adaptation of the secondary path estimating adaptive filter controlled, so that the secondary path estimate can be maintained irrespective of the presence and amplitude of the source audio.
    Type: Grant
    Filed: December 20, 2012
    Date of Patent: July 14, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: Jon D. Hendrix, Jeffrey Alderson, Antonio John Miller, Yang Lu
  • Patent number: 9076427
    Abstract: A personal audio device, such as a wireless telephone, generates an anti-noise signal from a microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. The microphone measures the ambient environment, but also contains a component due to the transducer acoustic output. An adaptive filter is used to estimate the electro-acoustical path from the noise-canceling circuit through the transducer to the at least one microphone so that source audio can be removed from the microphone signal. A determination of the relative amount of the ambient sounds present in the microphone signal versus the amount of the transducer output of the source audio present in the microphone signal is made to determine whether to update the adaptive response.
    Type: Grant
    Filed: March 7, 2013
    Date of Patent: July 7, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: Jeffrey Alderson, Jon D. Hendrix, Yang Lu
  • Publication number: 20150189434
    Abstract: A personal audio device including earspeakers, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each earspeaker from at least one microphone signal that measures the ambient audio, and the anti-noise signals are combined with source audio to provide outputs for the earspeakers. The anti-noise signals cause cancellation of ambient audio sounds at the respective earspeakers. A processing circuit uses the microphone signal(s) to generate the anti-noise signals, which can be generated by adaptive filters. The processing circuit controls adaptation of the adaptive filters such that when the processing circuit detects that either of the earspeakers are off-ear, a gain applied to the anti-noise signals is reduced.
    Type: Application
    Filed: March 12, 2015
    Publication date: July 2, 2015
    Inventors: Jon D. Hendrix, Jeffrey Alderson
  • Patent number: 9014387
    Abstract: A personal audio device including earspeakers, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each earspeaker from at least one microphone signal that measures the ambient audio, and the anti-noise signals are combined with source audio to provide outputs for the earspeakers. The anti-noise signals cause cancellation of ambient audio sounds at the respective earspeakers. A processing circuit uses the microphone signal(s) to generate the anti-noise signals, which can be generated by adaptive filters. The processing circuit controls adaptation of the adaptive filters such that when an event requiring action on the adaptation of one of the adaptive filters is detected, action is taken on the other one of the adaptive filters. Another feature of the ANC system uses microphone signals provided at both of the earspeakers to perform processing on a voice microphone signal that receives speech of the user.
    Type: Grant
    Filed: March 12, 2013
    Date of Patent: April 21, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: Jon D. Hendrix, Jeffrey Alderson
  • Publication number: 20150104032
    Abstract: A personal audio device, such as a wireless telephone, includes noise canceling circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone may also be provided proximate the speaker to estimate an electro-acoustical path from the noise canceling circuit through the transducer. A processing circuit uses the reference and/or error microphone, optionally along with a microphone provided for capturing near-end speech, to determine whether one of the reference or error microphones is obstructed by comparing their received signal content and takes action to avoid generation of erroneous anti-noise.
    Type: Application
    Filed: December 22, 2014
    Publication date: April 16, 2015
    Inventors: Nitin Kwatra, Jeffrey Alderson, Jon D. Hendrix
  • Patent number: 8958571
    Abstract: A personal audio device, such as a wireless telephone, includes noise canceling circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone may also be provided proximate the speaker to estimate an electro-acoustical path from the noise canceling circuit through the transducer. A processing circuit uses the reference and/or error microphone, optionally along with a microphone provided for capturing near-end speech, to determine whether one of the reference or error microphones is obstructed by comparing their received signal content and takes action to avoid generation of erroneous anti-noise.
    Type: Grant
    Filed: September 30, 2011
    Date of Patent: February 17, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: Nitin Kwatra, Jeffrey Alderson, Jon D. Hendrix