Cirrus Logic Inc.

Amazon Technologies, Inc.

Cirrus Logic International Semiconductor Limited

Rong Hu

Jie Su

Harsha Rao

Carl Lennart Ståhl

Roberto Napoli

Vadim A Konradi

Anthony Stephen Doy

Jason William Lawrence

Teemu Ramo

Firas Azrai

Roger David Serwy

Stefan Williams

Carlo Murgia

Amit Singh Chhetri

Marco A Janko

Pradeep Kumar Govindaraju

Kyle Wilkinson

Mrudula V Athi

Zheng Yan

Biqing Wu

Phil Hetherington

Vadim Konradi

Carl Lennart STÅHL

A system configured to improve audio processing by performing dereverberation and noise reduction during a communication session. In some examples, the system may include a deep neural network (DNN) configured to perform speech enhancement, which is located after an Acoustic Echo Cancellation (AEC) component. For example, the DNN may process isolated audio data output by the AEC component to jointly mitigate additive noise and reverberation. In other examples, the system may include a DNN configured to perform acoustic interference cancellation, which may jointly mitigate additive noise, reverberation, and residual echo, removing the need to perform residual echo suppression processing. The DNN is configured to process complex-valued spectrograms corresponding to the isolated audio data and/or estimated echo data generated by the AEC component.

Dereverberation and noise reduction

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 system that performs automatic gain control (AGC) using different decay rates. The system may select a slow decay rate to track a loudness level within speech (e.g., within an utterance), improving audio quality and maintaining dynamic range for an individual voice, while selecting a fast decay rate to track the loudness level after a gap of silence (e.g., no voice activity detected for a duration of time) or during large level changes (e.g., actual speech loudness is lower than estimated speech loudness for a duration of time). This improves an accuracy of the loudness estimate and therefore a responsiveness of the automatic gain control, resulting in an improved user experience.

Responsive automatic gain control

According to embodiments described herein, there are provided methods and apparatus for providing a driving signal to a transducer, wherein the driving signal is output by an amplifier. A method comprises receiving an indication of a voltage and a current of the driving signal; based on an electrical model of the transducer and the voltage and the current of the driving signal, estimating an estimated electrical response of the transducer representative of movement of a mass in the transducer; comparing the estimated electrical response to a desired electrical response; and controlling the driving signal based on the comparison.

Methods and apparatus for driving a transducer

Embodiments described herein provide methods and apparatus for outputting a haptic signal to a haptic transducer. A method comprises storing a representation of a part of the haptic signal comprising a first information point indicating a first amplitude and at least one first frequency of the part of the haptic signal at a first time, wherein the representation is associated with a user experience; responsive to receiving an indication of occurrence of the user experience, determining the haptic signal based on the first information point such that the part of the haptic signal has the first amplitude and the at least one first frequency at the first time. The method may further comprise outputting the haptic signal to the haptic transducer.

Methods and apparatus for outputting a haptic signal to a haptic transducer

A method may include generating an electrical drive waveform associated with a target actuator by stretching or compressing a reference drive waveform associated with a reference actuator in a time domain of the reference drive waveform in accordance with a time adjustment factor, wherein the time adjustment factor is determined based on a difference between a resonant frequency of the target actuator and a resonant frequency of the reference actuator. The same or another method may include generating an electrical drive waveform associated with a target actuator by increasing or decreasing an amplitude of a reference drive waveform associated with a reference actuator in accordance with an amplitude adjustment factor, wherein the amplitude adjustment factor is determined based on a difference between a resonant frequency of the target actuator and a resonant frequency of the reference actuator.

Drive waveform adjustments to compensate for transducer resonant frequency

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.

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

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.

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;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.

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

Speaker protection may be based on multiple speaker models with oversight logic that controls the speaker protection based on the multiple speaker models. At least one of the speaker models may be based on a speaker excursion determined from feedback information from the speaker, such as a current or voltage measured at the speaker. Excursion based on the speaker feedback may be used to determine an error in an excursion prediction made from the audio signal. The excursion prediction may then be compensated for that error. In some embodiments, a direct displacement estimate of excursion generated from speaker monitor signals is used to correct a fixed excursion model applied to an input audio signal.

Speaker protection excursion oversight

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.

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Austin, TX, United States of America

Rong Hu