Patents by Inventor Jon D. Hendrix

Jon D. Hendrix 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: 10468048
    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: December 22, 2014
    Date of Patent: November 5, 2019
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Nitin Kwatra, Jeffrey Alderson, Jon D. Hendrix
  • Patent number: 10382864
    Abstract: In accordance with systems and methods of the present disclosure, a method may include receiving an error microphone signal indicative of an acoustic output of a transducer and ambient audio sounds at the acoustic output of the transducer. The method may also include generating an anti-noise signal to reduce the presence of the ambient audio sounds at the acoustic output of the transducer based at least on the error microphone signal. The method may further include generating an equalized source audio signal from a source audio signal by adapting, based at least on the error microphone signal, a response of the adaptive playback equalization system to minimize a difference between the source audio signal and the error microphone signal. The method may additionally include combining the anti-noise signal with the equalized source audio signal to generate an audio signal provided to the transducer.
    Type: Grant
    Filed: December 10, 2013
    Date of Patent: August 13, 2019
    Assignee: Cirrus Logic, Inc.
    Inventors: Jeffrey D. Alderson, Jon D. Hendrix
  • Patent number: 10290296
    Abstract: An integrated circuit may include an output for providing an output signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer, an ambient microphone input for receiving an ambient microphone signal indicative of the ambient audio sounds; an error microphone input for receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer; and a processing circuit that implements a feedback path having a feedback response that generates a feedback anti-noise signal from the error microphone signal, wherein a signal gain of the feedback path is a function of the ambient microphone signal, and wherein the anti-noise signal comprises at least the feedback anti-noise signal.
    Type: Grant
    Filed: October 28, 2016
    Date of Patent: May 14, 2019
    Assignee: Cirrus Logic, Inc.
    Inventors: Jon D. Hendrix, Jeffrey D. Alderson, Chin Huang Yong, Ryan A. Hellman
  • Patent number: 10206032
    Abstract: In accordance with the present disclosure, an integrated circuit for implementing at least a portion of a personal audio device may include an output and a processing circuit. The output may provide an output signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer. The processing circuit may implement an adaptive noise cancellation system that generates the anti-noise signal to reduce the presence of the ambient audio sounds heard by the listener by adapting, based on a presence of the source audio signal, a response of the adaptive noise cancellation system to minimize the ambient audio sounds at the acoustic output of the transducer, wherein the adaptive noise cancellation system is configured to adapt both in the presence and the absence of the source audio signal.
    Type: Grant
    Filed: August 8, 2013
    Date of Patent: February 12, 2019
    Assignee: Cirrus Logic, Inc.
    Inventors: Jeffrey D. Alderson, Jon D. Hendrix, Antonio J. Miller, Robert G. Kratsas, Jens-Peter B. Axelsson, Dayong Zhou, Yang Lu, Chin Huang Yong
  • Patent number: 10181315
    Abstract: In accordance with the present disclosure, an adaptive noise cancellation system may include a controller. The controller may be configured to determine a degree of convergence of an adaptive coefficient control block for controlling an adaptive response of the adaptive noise cancellation system. The controller may enable adaptation of the adaptive coefficient control block if the degree of convergence of the adaptive response is below a particular threshold and disable adaptation of the adaptive coefficient control block if the degree of convergence of the adaptive response is above a particular threshold, such that when the adaptive noise cancellation system is adequately converged, the adaptive noise cancellation system may conserve power by disabling one or more of its components.
    Type: Grant
    Filed: June 13, 2014
    Date of Patent: January 15, 2019
    Assignee: Cirrus Logic, Inc.
    Inventors: Jeffrey D. Alderson, Jon D. Hendrix, Dayong Zhou
  • Patent number: 10152960
    Abstract: An integrated circuit may include an output for providing a signal to a transducer 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 microphone input for receiving a microphone signal indicative of ambient sounds at the transducer, a link control input for receiving link control information of a communications link coupling the integrated circuit to the transducer and/or a microphone for generating the microphone signal, wherein the link control information includes a link quality metric of the communications link, and a processing circuit comprising a filter having a response that generates the anti-noise signal in conformity with the microphone signal to minimize the ambient sounds at the acoustic output of the transducer, wherein the processing circuit modifies generation of the anti-noise signal responsive to the link quality metric.
    Type: Grant
    Filed: February 25, 2016
    Date of Patent: December 11, 2018
    Assignee: Cirrus Logic, Inc.
    Inventors: Jon D. Hendrix, Nitin Kwatra, Jeffrey D. Alderson
  • Patent number: 10013966
    Abstract: In accordance with embodiments of the present disclosure, a processing circuit may implement an adaptive filter, a first signal injection portion which injects a first additional signal into a first frequency range content source audio signal, and a second signal injection portion which injects a second additional signal into a second frequency range content source audio signal, wherein the first additional signal and the second additional signal are substantially different.
    Type: Grant
    Filed: March 15, 2016
    Date of Patent: July 3, 2018
    Assignee: Cirrus Logic, Inc.
    Inventors: Nitin Kwatra, Jon D. Hendrix, John L. Melanson
  • Patent number: 9955250
    Abstract: A personal audio device including multiple output transducers for reproducing different frequency bands of a source audio signal, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each of the transducers from at least one microphone signal that measures the ambient audio to generate anti-noise signals. The anti-noise signals are generated by separate adaptive filters such that the anti-noise signals cause substantial cancelation of the ambient audio at their corresponding transducers. The use of separate adaptive filters provides low-latency operation, since a crossover is not needed to split the anti-noise into the appropriate frequency bands. The adaptive filters can be implemented or biased to generate anti-noise only in the frequency band corresponding to the particular adaptive filter. The anti-noise signals are combined with source audio of the appropriate frequency band to provide outputs for the corresponding transducers.
    Type: Grant
    Filed: July 6, 2016
    Date of Patent: April 24, 2018
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Jon D. Hendrix, Jeffrey Alderson, Ali Abdollahzadeh Milani, Dayong Zhou, Yang Lu
  • Patent number: 9812114
    Abstract: A method may include adaptively generating an anti-noise signal for countering the effects of ambient audio sounds at an acoustic output of the transducer by adapting a response of an adaptive filter that filters a reference microphone signal in conformity with an error microphone signal and the reference microphone signal to minimize the ambient audio sounds in the error microphone, generating a scaled anti-noise signal by applying a scaling factor to the anti-noise signal, further adjusting the response of the adaptive filter independent of a source audio signal by altering an input to the coefficient control block of the adaptive filter to compensate for the scaling factor, and combining the scaled anti-noise signal with the source audio signal to generate an audio signal provided to the transducer.
    Type: Grant
    Filed: March 2, 2016
    Date of Patent: November 7, 2017
    Assignee: Cirrus Logic, Inc.
    Inventors: Jeffrey D. Alderson, Jon D. Hendrix, Sang-Ik Terry Cho, Chin Huang Yong, John L. Melanson
  • Patent number: 9807503
    Abstract: In accordance with embodiments of the present disclosure, an adjustable equalization filter may have a response that generates an equalized source audio signal from a source audio signal to account for effects of changes in an electro-acoustical path of the source audio signal to a transducer. An equalizer coefficient control block may adapt the response of the adjustable equalization filter in response to changes in a response of a secondary path estimate filter for modeling the electro-acoustical path of a source audio signal through the transducer, wherein a response of the secondary path estimate filter is adapted in conformity with an error microphone signal indicative of the acoustic output of the transducer.
    Type: Grant
    Filed: September 21, 2016
    Date of Patent: October 31, 2017
    Assignee: Cirrus Logic, Inc.
    Inventors: Bryant E. Sorensen, Jon D. Hendrix, John L. Melanson
  • Patent number: 9773490
    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: Grant
    Filed: June 9, 2015
    Date of Patent: September 26, 2017
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Jeffrey Alderson, Jon D. Hendrix, Dayong Zhou, Antonio John Miller, Chin Yong, Gautham Devendra Kamath
  • Patent number: 9773493
    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: November 23, 2015
    Date of Patent: September 26, 2017
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Yang Lu, Dayong Zhou, Jon D. Hendrix, Jeffrey Alderson
  • Publication number: 20170270906
    Abstract: In accordance with embodiments of the present disclosure, a processing circuit may implement an adaptive filter, a first signal injection portion which injects a first additional signal into a first frequency range content source audio signal, and a second signal injection portion which injects a second additional signal into a second frequency range content source audio signal, wherein the first additional signal and the second additional signal are substantially different.
    Type: Application
    Filed: March 15, 2016
    Publication date: September 21, 2017
    Applicant: Cirrus Logic International Semiconductor Ltd.
    Inventors: Nitin Kwatra, Jon D. Hendrix, John L. Melanson
  • Publication number: 20170256248
    Abstract: A method may include adaptively generating an anti-noise signal for countering the effects of ambient audio sounds at an acoustic output of the transducer by adapting a response of an adaptive filter that filters a reference microphone signal in conformity with an error microphone signal and the reference microphone signal to minimize the ambient audio sounds in the error microphone, generating a scaled anti-noise signal by applying a scaling factor to the anti-noise signal, further adjusting the response of the adaptive filter independent of a source audio signal by altering an input to the coefficient control block of the adaptive filter to compensate for the scaling factor, and combining the scaled anti-noise signal with the source audio signal to generate an audio signal provided to the transducer.
    Type: Application
    Filed: March 2, 2016
    Publication date: September 7, 2017
    Applicant: Cirrus Logic International Semiconductor Ltd.
    Inventors: Jeffrey D. Alderson, Jon D. Hendrix, Sang-Ik Terry Cho, Chin Huang Yong, John L. Melanson
  • Patent number: 9721556
    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: March 15, 2016
    Date of Patent: August 1, 2017
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Dayong Zhou, Yang Lu, Jon D. Hendrix, Jeffrey Alderson, Antonio John Miller, Chin Yong, Gautham Devendra Kamath
  • Patent number: 9711130
    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: April 15, 2016
    Date of Patent: July 18, 2017
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Jon D. Hendrix, Gautham Devendra Kamath, Nitin Kwatra, Ali Abdollahzadeh Milani, Jeffrey Alderson
  • Publication number: 20170133000
    Abstract: An integrated circuit may include an output for providing an output signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer, an ambient microphone input for receiving an ambient microphone signal indicative of the ambient audio sounds; an error microphone input for receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer; and a processing circuit that implements a feedback path having a feedback response that generates a feedback anti-noise signal from the error microphone signal, wherein a signal gain of the feedback path is a function of the ambient microphone signal, and wherein the anti-noise signal comprises at least the feedback anti-noise signal.
    Type: Application
    Filed: October 28, 2016
    Publication date: May 11, 2017
    Applicant: Cirrus Logic International Semiconductor Ltd.
    Inventors: Jon D. HENDRIX, Jeffrey D. ALDERSON, Chin Huang YONG, Ryan A. HELLMAN
  • Patent number: 9633646
    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: August 31, 2015
    Date of Patent: April 25, 2017
    Assignee: CIRRUS LOGIC, INC
    Inventors: Jon D. Hendrix, Ali Abdollahzadeh Milani, Nitin Kwatra, Dayong Zhou, Yang Lu, Jeffrey Alderson
  • Publication number: 20170084263
    Abstract: An integrated circuit may include an output for providing a signal to a transducer 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 microphone input for receiving a microphone signal indicative of ambient sounds at the transducer, a link control input for receiving link control information of a communications link coupling the integrated circuit to the transducer and/or a microphone for generating the microphone signal, wherein the link control information includes a link quality metric of the communications link, and a processing circuit comprising a filter having a response that generates the anti-noise signal in conformity with the microphone signal to minimize the ambient sounds at the acoustic output of the transducer, wherein the processing circuit modifies generation of the anti-noise signal responsive to the link quality metric.
    Type: Application
    Filed: February 25, 2016
    Publication date: March 23, 2017
    Applicant: Cirrus Logic International Semiconductor Ltd.
    Inventors: Jon D. Hendrix, Nitin Kwatra, Jeffrey D. Alderson
  • Patent number: 9532139
    Abstract: A frequency domain method and system for online self-calibrating microphone frequency amplitude response based on noise floor (minima) tracking are disclosed. A cellular telephone or other system with dual microphones may self-calibrate itself on-the-fly. The system selects one of the microphones as a reference and calibrates the frequency response of the two microphones using the first microphone as a reference, so that they have a matched frequency amplitude response. To achieve this on-the-fly calibration, the system uses background noise for calibration purposes. The signal power spectra of the noise minima at the two microphones is used to calibrate the respective microphone frequency response. The system may then adapt the frequency amplitude responses of the two microphones so that the power spectral density from each microphone matches the other, and the system is then calibrated.
    Type: Grant
    Filed: December 20, 2012
    Date of Patent: December 27, 2016
    Assignee: Cirrus Logic, Inc.
    Inventors: Yang Lu, Dayong Zhou, Jon D. Hendrix, Jeffrey Alderson