Cirrus Logic Inc.

Sigmatel, Inc.

Freescale Semiconductor,inc.

Motorola Corporation

Other

Cirrus Logic International Semiconductors, Ltd.

Jon David Hendrix

Jeffrey Donald Alderson

Dayong Zhou

Yang Lu

Nitin Kwatra

Gautham Devendra Kamath

Ali Abdollahzadeh Milani

Antonio John Miller

Chin Huang Yong

Michael R May

John L Melanson

Emmanuel A Marchais

Junsong Li

Charles Eric Seaberg

Ning Li

Bryant Sorensen

Thomas Glen Ragan

Shahram Tadayon

Raghu G Raj

Roy Scott Kaller

Aaron Treptow

Siddharth Maru

Eric Lindemann

Jie Su

Thomas Ivan Harvey

Dana John Taipale

Vitaliy Sapozhnykov

Pablo Peso Parada

K Joshua Bodon

Brian Thornock

Marco A Janko

Robert Luke

Ryan A Hellman

Anthony John Shilton

Rahul Gawde

Josh Sanz-Robinson

Tom Harvey

Viral Parikh

Bradley A Banks

Robert George Kratsas

Jens-Peter B Axelsson

Sang-Ik Terry Cho

Sam Waters

Glen Ragan

Nafiseh Erfanian Saeedi

Noel Preecs

Bryant Tran

Nicholas Joseph

Robert G Kratsas

Milani Ali Abdollahzadeh

A classification system for classifying sensor samples in a sensor system, the sensor system comprising N force sensors each configured to output a sensor signal, where N≥1, each sensor sample comprising N sample values from the N sensor signals, respectively, the classification system comprising: a classifier configured, for each of a series of candidate sensor samples, to perform a classification operation based on the N sample values concerned and generate a classification result which labels the candidate sensor sample as indicative of a defined target event, thereby generating a series of classification results corresponding to the series of candidate sensor samples, respectively; a determiner configured to output at least one event determination based on the series of classification results; and a controller configured to control the classifier and/or the determiner based on one or more controller input signals.

Force sensor sample classification

A method may include selecting, based on a condition of an electromagnetic load, a selected measurement technique from a plurality of impedance measurement techniques for measuring an impedance of the electromagnetic load and performing the selected measurement technique to generate an estimate of the impedance of the electromagnetic load.

Methods and systems for estimating coil impedance of an electromagnetic transducer

A method may include receiving, by a transducer driving system, a first signal for driving an amplifier that drives an electromagnetic load and receiving, by the transducer driving system, a second signal driven by the amplifier in order to control a feedback loop of the transducer driving system. The method may also include detecting unexpected spectral content in the second signal, declaring an indicator event based on the detected unexpected spectral content, determining whether the indicator event occurs in an undesired pattern, and in response to the indicator event occurring in the undesired pattern, modifying a behavior of the transducer driving system.

Methods and systems for detecting and managing unexpected spectral content in an amplifier system

In accordance with embodiments of the present disclosure, a method of driving a playback waveform to an electromagnetic actuator by a transducer driving system may include operating the transducer driving system in a first mode wherein the electromagnetic actuator is driven with the playback waveform in a closed loop to form a closed-loop voltage drive system that includes a negative impedance, operating the transducer driving system in a second mode wherein the electromechanical actuator is driven with the playback waveform in an open loop, and operating a mode switch for transitioning the transducer driving system to operate between the first mode and the second mode.

Methods and systems for managing mixed mode electromechanical actuator drive

A method may include receiving a user trigger signal indicating a user desire to update characteristics of an adaptive filter, receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer, wherein the transducer reproduces 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, implementing the adaptive filter having a response that generates the anti-noise signal to reduce the presence of the ambient audio sounds in the error microphone signal, determining an acoustic coupling of the transducer to an error microphone for producing the error microphone signal, and responsive to a change in the acoustic coupling, prompting a user to assert the user trigger signal to indicate user desire to update characteristics of the adaptive filter.

On-demand adaptive active noise cancellation system

An integrated circuit for implementing at least a portion of a personal audio device may include an output for providing an output signal to a transducer, wherein the output signal includes a pilot signal, a microphone input for receiving a microphone signal from a microphone indicative of an output of the transducer, and a processing circuit. The processing circuit may be configured to implement a pilot signal control to apply an adjustment to the pilot signal as necessary to maintain the pilot signal at a substantially constant magnitude regardless of proximity of the transducer to a pinna and implement a proximity determination block configured to determine proximity of the transducer to the pinna based on the adjustment.

Pinna proximity detection

On-demand adaptive active noise cancellation

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.

Mic covering detection in personal audio devices

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.

Systems and methods for providing adaptive playback equalization in an audio device

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.

Feedback howl management in adaptive noise cancellation system

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.

Systems and methods for multi-mode adaptive noise cancellation for audio headsets

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.

Systems and methods for selectively enabling and disabling adaptation of an adaptive noise cancellation system

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.

Systems and methods for distributed adaptive noise cancellation

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. The adaptive filter may have a response that generates the antinoise signal from the reference microphone signal to reduce the presence of the ambient audio sounds at the acoustic output, wherein the response of the adaptive filter is shaped in conformity with the reference microphone signal and the error microphone signal by adapting the response of the adaptive filter to minimize the ambient audio sounds in the error microphone signal, wherein the antinoise signal is combined with at least the first frequency range content source audio signal.

Systems and methods for adaptive active noise cancellation for multiple-driver personal audio device

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.

Low-latency multi-driver adaptive noise canceling (ANC) system for a personal audio device

Growing community of inventors

Wimberly, TX, United States of America

Jon David Hendrix