Cirrus Logic Inc.

Freescale Semiconductor,inc.

Microsoft Technology Licensing, LLC

Alcatel Lucent

Motorola Corporation

Lucent Technologies Inc.

Alcatel-lucent USA Inc.

Freescale Semiconductors Inc.

Cirrus Logic International Semiconductor Limited

Jie Su

Rong Hu

Roberto Napoli

Yigang Cai

Antonio John Miller

Jason William Lawrence

Firas Azrai

Roger David Serwy

Harsha Rao

Jian Wang

Anthony Stephen Doy

Carl Lennart Ståhl

Vadim A Konradi

Min Chu

Wenli Zhu

Teemu Ramo

Stefan Williams

Samuel Oyetunji

Qinghong He

Ke Pei

John L Melanson

Jeffrey Donald Alderson

Jon David Hendrix

Junsong Li

Jeffrey Allen May

Ali Abdollahzadeh Milani

Charles Eric Seaberg

Ning Li

Sheng Chen

John Brian Reid

Jay Z Zhao

Khosrow Lashkari

Kaichow Lau

Ya Wu

Yui-Luen J Ho

Yong Wang

Ziad Hatab

Ling Jiang

Waleed Eshmawy

Judith A Stafford

Sunil Thadani

Jungsong Li

Chao Liang Zhang

Zheng Yan

Hezi Zhu

Chaoliang Zhang

Vadim Konradi

Carl Lennart STÅHL

An integrated haptic system may include a digital signal processor and an amplifier communicatively coupled to the digital signal processor and integrated with the digital signal processor into the integrated haptic system. The digital signal processor may be configured to receive a force sensor signal indicative of a force applied to a force sensor and generate a haptic playback signal responsive to the force. The amplifier may be configured to amplify the haptic playback signal and drive a vibrational actuator communicatively coupled to the amplifier with the haptic playback signal as amplified by the amplifier.

Integrated haptic system

A method for processing audio data for output to a transducer may include receiving an audio signal, filtering the audio signal with a fixed filter having fixed filter coefficients to generate a filtered audio signal, and outputting the filtered audio signal to the transducer. The fixed filter coefficients of the fixed filter may be tuned by using a psychoacoustic model of the transducer to determine audibility masking thresholds for a plurality of frequency sub-bands, allocating compensation coefficients to the plurality of frequency sub-bands, and fitting the fixed filter coefficients with the compensation coefficients allocated to the plurality of sub-bands.

Psychoacoustics for improved audio reproduction, power reduction, and speaker protection

Embodiments described herein relate to methods and apparatus for driving a haptic transducer with a driving signal. The method comprises estimating, based on a current through the haptic transducer and a terminal voltage across the haptic transducer, a back electromotive force, EMF, voltage representative of a velocity of a mass in the haptic transducer; comparing a phase of a voltage signal derived from the terminal voltage with a phase of the estimated back EMF voltage; and based on the comparison, adjusting a frequency or a phase of an output signal, wherein the driving signal is derived from the output signal, such that a frequency of the driving signal converges to a resonant frequency of the haptic transducer.

Methods and apparatus for driving a transducer

A method for quantifying fidelity of a haptic signal may include receiving a response signal indicative of a vibrational response of a vibrational transducer to a haptic playback waveform driven to the vibrational transducer, perceptually filtering the response signal to obtain human haptic-perceptible components of the response signal, and quantifying fidelity of the haptic playback waveform based on at least one quantitative characteristic of the human haptic-perceptible components of the response signal.

Vibro-haptic design and automatic evaluation of haptic stimuli

A method for compensating for a change in back electric motive force in a transducer in a device, wherein the transducer is driven by an output signal output by an amplifier, and a back volume of the transducer is formed by an enclosure within the device. The method comprises: receiving an input signal; determining, based on a characteristic of the transducer that the transducer has moved from an equilibrium position within the device; and based on the determination, adjusting a gain applied to the input signal by the amplifier to generate the output signal.

Audio distortion compensation

This application describes methods and apparatus for loudspeaker protection. A loudspeaker protection system () is described having a first frequency band-splitter () for splitting an input audio signal (Vin) into a plurality of audio signals (v, v. . . , vn) in different respective frequency bands (&#x3c9;. . . , &#x3c9;n). A first gain block () is configured to apply a respective frequency band gain (g, g. . . , g) to each of the audio signals in the different respective frequency bands and a gain controller () is provided for controlling the respective band gains. A displacement modeller () determines a plurality of displacement signals (x, x. . . , xn) based on the input audio signal (Vin) and a displacement model () where each displacement signal corresponds to a modelled cone displacement for the loudspeaker for one of said different respective frequency bands. The gain controller () is configured to control the respective frequency band gains based on the plurality of displacement signals.

Loudspeaker protection

This application describes methods and apparatus for loudspeaker protection. A loudspeaker protection system () is described having a first frequency band-splitter () for splitting an input audio signal (Vin) into a plurality of audio signals (v, v. . . ,vn) in different respective frequency bands (&#x3c9;. . . &#x3c9;&#x3b7;). A first gain block () is configured to apply a respective frequency band gain (gt, gt. . . ,gt) to each of the audio signals in the different respective frequency bands and a gain controller () is provided for controlling the respective band gains. A thermal controller () determines, for each of a plurality of the different respective frequency bands, a power dissipation for the loudspeaker in that frequency band and also determines a respective thermal gain setting based on the determined power dissipation for that frequency band. The gain controller is configured to control the respective frequency band gains based on the thermal gain settings.

A speaker model may implement a direct voltage-to-excursion model in an adaptive filter for modeling the speaker without developing a first electrical-only model and then converting the model to a mechanical model. The voltage-to-excursion model may allow for modeling of different kinds of speakers, such as sealed, ported, or vented speakers. A transfer function may be developed in the adaptive filter for the voltage-to-excursion model, and that transfer function re-used for prediction of excursion values based on an audio signal. Speaker protection may be performed to take steps to prevent speaker damage when a predicted excursion value exceeds safe limits. The voltage-to-excursion model may operate in displacement or displacement-related domains (e.g., velocity and back emf).

Speaker adaptation with voltage-to-excursion conversion

The reliability and resilience of a speaker in a portable device may be improved by enabling the device to determine a status of an enclosure of a transducer. The impedance profiles of transducers vary depending on the enclosure status, whether the enclosure is leaky, ported, or sealed. Determination of parameters related to an impedance of a transducer may aid in a determination of the status of the enclosure. Once an enclosure status is determined, that information may be used to determine an excursion model for the transducer. Adapting the excursion model or other audio processing parameters can improve protection and performance of the transducer.

Speaker enclosure status

A predictive brownout prevention system may be configured to prevent brownout of an audio output signal. Particularly, the brownout prevention system may be configured to receive information indicative of adaptive estimates of power supply conditions, wherein the information indicative of adaptive estimates of the power supply conditions comprises information regarding a voltage component and a resistive component received from an adaptive battery model of a battery for providing electrical energy to a power supply for generating the power supply voltage and adapt the adaptive battery model based on a monitored battery voltage output by the battery and loading events of the signal path and excluding loading events of components other than the signal path which are powered from the battery.

Method for limiting amplifier input current to avoid low voltage conditions

Commands for modifying audio playback, such as to mute and unmute or pause and play audio, may be input to a mobile device by a user through interacting with the speaker in the device. The user input may be facilitated by monitoring a characteristic of the speaker and identifying signatures in the changing characteristics of the speaker that correspond with predetermined user activities. For example, a resonance frequency of the speaker may be monitored for a change resulting from a user placing a hand to cover the speaker output. When the resonance frequency change is detected, the audio playback may be muted. The speaker may continue to be monitored for a change indicating removal of the user's hand, and then audio playback may be unmuted.

User input through transducer

In accordance with embodiments of the present disclosure, a method may include using an adaptive filter system to estimate a response of an electrical characteristic of a loudspeaker based on an error between a first electrical parameter of the loudspeaker and a second electrical parameter of the loudspeaker and adding a non-zero delay to the first electrical parameter relative to the second electrical parameter prior to calculation of the error such that the adaptive filter system captures a truncated non-causality of the electrical characteristic.

Systems and methods for loudspeaker electrical identification with truncated non-causality

In accordance with embodiments of the present disclosure, a controller configured to be coupled to an audio transducer, may be further configured to receive an audio input signal, calculate a displacement compensation signal in a displacement domain of the audio transducer based on the audio input signal, convert the displacement compensation signal from the displacement domain into a voltage compensation signal in a voltage domain, and apply the voltage compensation signal to the audio input signal, or a derivative thereof, to minimize overexcursion of the audio transducer.

Speaker protection from overexcursion

In accordance with embodiments of the present disclosure, a system may include a controller configured to be coupled to an audio speaker, wherein the controller receives an output signal indicative of a physical quantity associated with the audio speaker, compares the output signal to an audio input signal to determine if differences between the output signal and the audio input signal are present indicating at least one of distortion of the output signal, non-linearities of the audio speaker, and overexcursion of the audio speaker, and controls an audio signal communicated from the controller to the audio speaker and based on the audio input signal responsive to determining that differences between the output signal and the audio input signal are present indicating at least one of distortion of the output signal, non-linearities of the audio speaker, and overexcursion of the audio speaker.

Speaker protection based on output signal analysis

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Austin, TX, United States of America

Jie Su