Abstract: The present disclosure discloses an audio playback apparatus having noise-canceling mechanism that includes a sound receiving circuit, a storage circuit, a filter control circuit, a filter circuit and an audio playback circuit. The sound receiving circuit receives received audio signal including noise. The storage circuit stores filter parameters. The filter control circuit includes a noise estimation circuit, a noise distribution determination circuit and a parameter generation circuit. The noise estimation circuit receives the received audio signal and calculates a stationary noise power spectrum density of the noise such that the noise distribution determination circuit determines a noise spectrum distribution accordingly. The parameter generation circuit analyses the noise spectrum distribution and retrieves a group of selected filter parameters accordingly. The filter circuit filters the received sound signal according to the group of selected filter parameters to generate an anti-noise audio signal.

Abstract: A hearing device comprises an ITE-part adapted for being located at or in an ear canal of the user comprising a housing comprising a seal towards walls or the ear canal, the ITE part comprising at least two microphones located outside the seal and facing the environment, and at least one microphone located inside the seal and facing the ear drum. The hearing device may comprise a beamformer filter connected to said at least three microphones comprising a first beamformer for spatial filtering said sound in the environment based on input signals from said at least two microphones facing the environment, and a second beamformer for spatial filtering sound reflected from the ear drum based on said at least one electric input signal from said at least one microphone facing the ear drum and at least one of said input signals from said at least two microphones facing the environment.

Abstract: Various implementations include systems for processing inner microphone audio signals. In particular implementations, a system includes an external microphone configured to be acoustically coupled to an environment outside an ear canal of a user; an inner microphone configured to be acoustically coupled to an environment inside the ear canal of the user; and an adaptive noise cancelation system configured to process an internal signal captured by the inner microphone and generate a noise reduced internal signal, wherein the noise reduced internal signal is adaptively generated in response to an external signal captured by the external microphone.

Abstract: An embodiment for creating a virtual ambient workstation is provided. The embodiment may include receiving a request to reserve an ambient space for a determined time period. The embodiment may also include identifying one or more workstations that are occupied by one or more other individuals. The embodiment may further include identifying combined vocal-fold sound patterns provided to a cognitive system based on the identified one or more workstations occupied by the one or more other individuals. The embodiment may also include evaluating data obtained from the one or more workstations and the combined vocal-fold sound patterns. The embodiment may further include generating an ambient noise remediation sound using an acoustic beam system. The embodiment may also include training the cognitive system. The embodiment may further include determining whether a level of ambient sound is sufficient and providing feedback to the cognitive system through machine learning.

Abstract: A noise cancellation filter structure for a noise cancellation enabled audio device, in particular headphone, comprises a noise input for receiving a noise signal and a filter output for providing a filter output signal. A first noise filter produces a first filter signal by filtering the noise signal and a second noise filter produces a second filter signal by filtering the noise signal. The second noise filter has a frequency response with a non-minimum-phase, in particular maximum-phase. A combiner is configured to provide the filter output signal based on a linear combination of the first filter signal and the second filter signal.

Abstract: An audio system for a headset includes a plurality of speakers and an audio controller. The plurality of speakers may be in a dipole configuration that cancel sound leakage into a local area of the headset. The controller filters audio content presented by the plurality of speakers to further mitigate leakage of audio content into the local area. The audio determines sound filters based on environmental conditions, such as ambient noise levels, as well as based on the audio content being presented.

Abstract: Active noise-cancelling (ANC) headphones in the form of a part of a headset or as in-ear headphones that reduce acoustic adaptation by providing an electrodynamic speaker in a housing with ventilation openings and an acoustically permeable front panel. These components form a module that can be integrated into ANC headphones, permitting its installation in different headphones without customization. The module reacts to a reduction of the impermeability situation in such a manner, that an impedance change of the speaker takes place below 100 Hz. For example, a microphone and electronics with a feedback filter for active noise cancellation can be provided that form a secondary route between speaker and microphone. In a further development, an evaluation unit is provided which detects and evaluates a change in the impedance of the speaker and adapts the feedback loop.

Abstract: Herein provided is a signal processing device for use in an aircraft engine with a variable geometry mechanism (VGM) and associated systems and methods. The signal processing device comprises a processing unit and a non-transitory computer-readable memory communicatively coupled to the processing unit. The memory has stored thereon computer-readable program instructions executable by the processing unit for: obtaining a VGM position request signal; determining whether a variation of the VGM position request signal is within a predetermined range; when the variation of the VGM position request signal is within the predetermined range: filtering the VGM position request signal to reduce a level of noise in the VGM position request signal; and transmitting the filtered VGM position request signal; and when the variation of the VGM position request signal is not within the predetermined range, transmitting a processed signal, based on the VGM position request signal.

Abstract: The invention provides a method and apparatus for filtering a temporal signal. A target magnitude frequency response HT(f) is specified (101,201) of frequency f in terms of a column vector l of K weights lk where log HT(f)=lTW(f) and W(f) is a column vector of K magnitude basis functions Wk(f). A constrained frequency response Hc(f) is computed (102,214) defined by log Hc(f)=gTV(f) , where V(f) is a column vector of N constrained basis functions Vn(f) for which each exp gnVn(f) satisfies a constraint preserved by concatenation, and g is a column vector of N coefficients satisfying a matching criterion between lTW(f) and gTV(f). An input temporal signal is received (103,212) and filtered (104,210) with the constrained frequency response Hc(f) to form a filtered temporal signal; and the filtered temporal signal is output (105,211).

Abstract: A system and method includes an audio device, such as an earbud or headphones, that includes one or more loudspeakers for outputting audio. The audio device further in includes one or more microphones that are positioned near an ear of a user. An acoustic barrier may be formed between a surface of the device and the ear of the user; properties of this barrier may, however, vary from user to user. The system determines these properties on a per-user basis and compensates for any differences therein.

Abstract: A headset system comprises: a headset comprising at least one microphone and at least one speaker and configured to transmit and receive sound; a wire system coupled to the headset and comprising a wire; and a control unit coupled to the wire system and configured to: receive from the wire a combined signal comprising a first signal and a second signal, determine that the first signal is a spurious signal, and detect a failure of the wire system based on the determining.

Abstract: An adaptive active noise cancellation apparatus performs a filtering operation in a first digital domain and performs adaptation of the filtering operation in a second digital domain.

Abstract: Adaptive noise cancellation systems and methods include a reference sensor to sense environmental noise and generate a corresponding reference signal, an error sensor to sense noise in a noise cancellation zone and generate a corresponding error signal, a noise cancellation path including a noise cancellation filter and a variable gain component, the noise cancellation path receiving the reference signal and generating an anti-noise signal to cancel noise at an eardrum reference point, and an adaptation module to receive the reference signal and the error signal and adaptively adjust weights of the noise cancellation filter and/or the variable gain component. An adaptive gain control block updates the variable gain component. Inputs to the adaptive gain control block are conditioned using programmable filters to protect against low frequency transients and/or high frequency distractors in the environmental noise. The programmable filters are tuned to optimize cancellation at an eardrum reference point.

Abstract: An improved method for configuring an audio reproduction device for detecting sound and providing different output audio signals in a plurality of rooms where at least two wireless microphones connect via a local network to an audio streaming server. Each of the wireless microphones detects room information indicating the room in which it is located, and transmits it to the server, together with an input audio signal. The server compiles at least two different output audio signals according to the respective room information from the input audio signals, and assigns each to a room. The output audio signals are provided via the local network in the rooms such that each of the output audio signals may be received in all rooms, and may be replayed only in the room to which it has been assigned. Each wireless microphone may be used in each of the rooms.

Abstract: Systems and methods are provided for modifying an audio signal using custom psychoacoustic models. A user's hearing profile is first obtained. Subsequently, an audio processing function is parameterized so as to optimize the user's perceptually relevant information. The method for calculating the user's perceptually relevant information comprises first processing audio signal samples using the parameterized processing function and then transforming samples of the processed audio signals into the frequency domain. Next, masking and hearing thresholds are obtained from the user's hearing profile and applied to the transformed audio sample, wherein the user's perceived data is calculated. Once perceptually relevant information is optimized, the resulting parameters are transferred to the audio processing function and an output audio signal is processed.

Abstract: A control device (DC) is fitted to a vehicle (VA) which can be driven by a driver during a manual driving phase and which comprises a passenger compartment (H) fitted with a loudspeaker (HP) capable of diffusing sound signals and an assistance device (DA) for driving said vehicle in a totally autonomous manner during an autonomous driving phase. This device (DC) comprises acquisition means (MA) for recording first sound signals present in the external environment of the vehicle (VA), and control means (MC) for generating, during an autonomous driving phase, second sound signals in phase opposition to the first recorded sound signals, in order to supply same to the loudspeaker (HP) so that the transmission of said signals induces cancellation of the first sound signals in the passenger compartment (H).

Abstract: A configuration is implemented via a processor to receive a request to perform a service. Further, the configuration selects a human representative from a plurality of human representatives associated with a communication center based on a computing device associated with the human representative indicating that the human representative is online and available to perform the service. In addition, the configuration routes the request to the computing device associated with the human representative. The configuration also monitors activity of the human representative at the computing device associated with the human representative. Further, the configuration determines that the activity of the human representative is inconsistent with the human representative being available to perform the service. Finally, the configuration reroutes the request to a different computing device associated with a different human representative.

Abstract: An unmanned aerial vehicle (UAV) with audio filtering components includes a background noise-producing component, a background microphone, and a noise emitter. The background noise-producing component is configured to produce a background noise. The background microphone is positioned within a proximity sufficiently close to collect interfering noise from the background noise producing component. The background microphone is configured to collect audio data including the background noise. The noise emitter is disposed within a proximity sufficiently close to the background noise-producing component to reduce the interfering noise. The noise emitter is configured to emit an audio signal having a reverse phase of the audio data collected by the background microphone.

Abstract: Certain implementations of the disclosed technology may include systems and methods for extending a frequency response of a transducer. A method is provided that can include receiving a measurement signal from a transducer, wherein the measurement signal includes distortion due to a resonant frequency of the transducer. The method includes applying a complementary filter to the measurement signal to produce a compensated signal, wherein applying the complementary filter reduces the distortion to less than about +/?1 dB for frequencies ranging from about zero to about 60% or greater of the resonant frequency. The method further includes outputting the compensated signal.

Abstract: A system includes an audio broadcast device, headphones and an interface device. The audio broadcast device may be configured to generate a plurality of audio tracks. The headphones may be configured to perform noise cancellation of ambient audio, decode one of the plurality of audio tracks selected by a user and playback a personalized audio track in response to the selected audio track and user settings. The interface device may be configured to receive the user settings and enable the user to select one of the audio tracks. The headphones may receive the selected audio track from the audio broadcast device in response to the selection using the interface. The user settings may be applied to the selected audio track to generate the personalized audio track.

Abstract: Active noise reduction (ANR) headphones and associated methods are provided. The ANR headphones may include a memory to store a plurality of profiles each including controller information and acoustic parameters in addition to a profile selection routine executable by a processor of the ANR headphone. The profile selection routine may be configured to identify acoustic characteristics of a subject wearing the ANR headphone, compare the acoustic characteristics of the subject with the acoustic parameters of the plurality of profiles, select a profile from the plurality of profiles based on the comparison between the acoustic characteristics of the subject with the acoustic parameters of the selected profile, and provide the controller information of the selected profile to a noise reduction circuit of the ANR headphone.

Abstract: A sound playback device and a method for masking interference sound through a noise masking signal thereof are disclosed. The method comprises the steps of: playing an audio signal as a noise masking signal; receiving an ambient sound; analyzing whether the ambient sound has an interference sound in N different frequency bands; if so, finding at least one interference sound frequency band and a time period, and the interference sound conforms to the condition that an instant sound entropy value is greater than a dynamic sound average entropy value, wherein the instant sound entropy value is the calculated sound entropy value in a current sampling time; the dynamic sound average entropy value is an average entropy value of the sum of the previous instant sound entropy values; and increasing an energy of the noise masking signal in the interference sound frequency band and the time period.

Abstract: A noise reduction device includes a second corrector that generates a correction signal by correcting an output signal or a standard signal by a predetermined parameter and adds the generated correction signal to an error signal, to generate a corrected error signal approximating the error signal to an error signal indicating a residual sound occurring in a sound reception location.

Abstract: The technology described in this document can be embodied in a method that includes receiving an input signal representing audio captured by a microphone of an active noise reduction (ANR) headphone, and processing, by a first compensator, a first frequency range of the input signal to generate a first signal for an acoustic transducer of the ANR headphone. The method also includes processing, by a second compensator disposed in parallel to the first compensator, a second frequency range of the input signal to generate a second signal for the acoustic transducer. The first frequency range includes frequencies higher than the frequencies in the second frequency range. The method also includes detecting, by one or more processing devices, that the second signal satisfies a threshold condition, and attenuating the second signal responsive to determining that the second signal satisfies the threshold condition.

Abstract: Systems, methods, and devices for intelligent speech recognition and processing are disclosed. According to one embodiment, a method for improving intelligibility of a speech signal may include (1) at least one processor receiving an incoming speech signal comprising a plurality of sound elements; (2) the at least one processor recognizing a sound element in the incoming speech signal to improve the intelligibility thereof; (3) the at least one processor processing the sound element by at least one of modifying and replacing the sound element; and (4) the at least one processor outputting the processed speech signal comprising the processed sound element.

Abstract: A sound pickup device includes a plurality of microphones, and at least one processor configured to implement stored instructions and execute a plurality of tasks, including: a first gain controlling task controlling a gain of each of the plurality of microphones, an adding task adding a sound signal to be output from the first gain controlling task with a predetermined gain, a second gain controlling task controlling a gain of the sound signal to be output from the adding task; and a gain setting task setting each gain of the first gain controlling task based on gain setting in the second gain controlling task.

Abstract: A polymorphic playback system in which one or more parameters of a signal path of the polymorphic playback system are varied based on one or more characteristics of a playback signal processed by the signal path may include a control subsystem configured to detect an out-of-band noise profile of the playback signal and set one or more playback signal magnitude thresholds for switching between polymorphic modes of the polymorphic playback system based on the out-of-band noise profile, wherein the polymorphic modes comprise at least a first polymorphic mode in which one or more first parameters are applied to the signal path and a second polymorphic mode in which one or more second parameters are applied to the signal path.

Abstract: The present application describes techniques for noise control which utilize a feedback control unit comprising a filter, derived from one or more predetermined filter candidates, for reducing or cancelling a feedback component of a noise control signal.

Abstract: The handling of disturbances to audio signals may be improved with an adaptive noise cancellation (ANC) system that performs frequency-domain adaption. The ANC systems may be configured to determine if a disturbance is present at a first frequency in the second input signal received from the reference microphone. The ANC systems may update an algorithm of an adaptive filter based, at least in part, on the first input signal, the second input signal, and a feedback signal that is based on an output of the adaptive filter by changing parameters of the algorithm such that the adaptive filter adapts around the first frequency differently than other frequencies when the disturbance is present.

Abstract: A personal audio device, such as a wireless telephone, includes noise canceling 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 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. The anti-noise signal is adaptively generated to minimize the ambient audio sounds at the error microphone. A processing circuit that performs the adaptive noise canceling (ANC) function also filters one or both of the reference and/or error microphone signals, to bias the adaptation of the adaptive filter in one or more frequency regions to alter a degree of the minimization of the ambient audio sounds at the error microphone.

Abstract: A noise-cancelling headphone is provided that avoids an influence of the wind and prevents degradation in the sound quality of the reproduced sound output from a driver unit. The noise-cancelling headphone includes an ear piece including a housing unit having an interior and an exterior, a driver unit attached to the housing unit, and a microphone collecting external sounds at the exterior of the housing unit. The housing unit includes an accommodating portion accommodating the microphone and a sound collecting hole establishing the communication between the accommodating portion and the exterior of the housing unit. The accommodating portion is disposed in an upper portion of the housing unit of the noise-cancelling headphone when worn by the user. The sound collecting hole is open toward the upper side of the housing unit of the noise-cancelling headphone when worn by the user.

Abstract: Differing from conventionally-used exhaust pipe utilizing discontinuous section area(s) and sound-absorbing material(s) to abate the noise produced by an engine, the present invention provides a waste air exhausting device consisting of: a housing, a supporting plate disposed in the housing, a miniature microphone disposed at the end of the housing, and a loudspeaker disposed on the supporting plate. Therefore, according to the noise produced by the engine, a noise controller system coupling to the miniature microphone and the loudspeaker is able to produce an anti-noise signal through the loudspeaker for abating the engine noise. On the other hand, the noise controller system can also produce an anti-noise signal having specific frequencies components according to the frequency of the engine noise and a reference signal, so as to modulate the frequency of the engine noise by broadcasting the anti-noise signal having the specific frequencies components in the housing through the loudspeaker.

Abstract: An audio control system of a vehicle includes a sound control module configured to determine N magnitudes for outputting a predetermined engine sound at N frequencies, respectively, where N is an integer greater than one. A magnitude adjustment module is configured to determine at least one N magnitude adjustment values for the N frequencies, respectively, based on at least one of: an intake air temperature; and an exhaust temperature. The sound control module is further configured to determine N adjusted magnitudes for the predetermined engine sound at the N frequencies based on: the N magnitudes for the N frequencies, respectively; and the N magnitude adjustment values for the N frequencies, respectively. An audio driver module is configured to apply power to at least one speaker of the vehicle and output the predetermined engine sound at the N frequencies and the N adjusted magnitudes for the N frequencies, respectively.

Abstract: Digital signal processing techniques for automatically reducing audible noise from a sound recording that contains speech. A noise suppression system uses two types of noise estimators, including a more aggressive one and less aggressive one. Decisions are made on how to select or combine their outputs into a usable noise estimate in a different speech and noise conditions. A 2-channel noise estimator is described. Other embodiments are also described and claimed.

Abstract: A multichannel acoustic system (MAS) comprises an arrangement of microphones and loudspeakers and a multichannel acoustic processor (MAP) to together enhance conversational speech between two or more persons in a shared acoustic space such as an automobile. The enhancements are achieved by receiving sound signals substantially originating from relatively near sound sources; filtering the sound signals to cancel at least one echo signal detected for at least one microphone from among the plurality of microphones; filtering the sound signals received by the plurality of microphones to cancel at least one feedback signal detected for at least one microphone from among the plurality of microphones; and reproducing the filtered sound signals for each microphone from among the plurality of microphones on a subset of loudspeakers corresponding that are relatively far from the source microphone.

Abstract: Systems, apparatuses and methods for integrating adaptive noise cancellation (ANC) with communication features in an enclosure, such as an incubator, bed, and the like. Utilizing one or more error and reference microphones, a controller for a noise cancellation portion reduces noise within a quiet area of the enclosure. Voice communications are provided to allow external voice signals to be transmitted to the enclosure with minimized interference with noise processing. Vocal communications from within the enclosure may be processed to determine certain characteristics/features of the vocal communications. Using these characteristics, certain emotive and/or physiological states may be identified.

Abstract: In accordance with systems and methods of this disclosure, a method may include generating a feedforward anti-noise signal component from a result of measuring with the reference microphone countering the effects of ambient audio sounds at an acoustic output of a transducer by filtering an output of the reference microphone, adaptively generating a feedback anti-noise signal component from a result of measuring with an error microphone for countering the effects of ambient audio sounds at the acoustic output of the transducer by adapting a response of a feedback adaptive filter that filters a synthesized reference feedback to minimize the ambient audio sounds in the error microphone signal, wherein the synthesized reference feedback is based on a difference between the error microphone signal and the feedback anti-noise signal component.

Abstract: In accordance with methods and systems of the present disclosure, a processing circuit may implement a feedback filter having a response that generates a feedback anti-noise signal component from a playback corrected error, the playback corrected error based on a difference between an error microphone signal and a secondary path estimate, and wherein the anti-noise signal comprises at least the feedback anti-noise signal component, a secondary path estimate filter configured to model an electro-acoustic path of the source audio signal and have a response that generates a secondary path estimate from the source audio signal, and a secondary coefficient control block that shapes the response of the secondary path estimate adaptive filter in conformity with a source audio signal and the playback corrected error by adapting the response of the secondary path estimate adaptive filter to minimize the playback corrected error.

Abstract: An audio beamformer receives signals from microphones of an array and processes the signals to produce a directional audio signal that emphasizes sound from a selected direction. The beamformer is implemented using weights or other parameters that are calculated to account for effects upon the received audio signals by the surfaces upon which the microphones are positioned.

Abstract: Noises that are to be emitted by an aerial vehicle during operations may be predicted using one or more machine learning systems, algorithms or techniques. Anti-noises having equal or similar intensities and equal but out-of-phase frequencies may be identified and generated based on the predicted noises, thereby reducing or eliminating the net effect of the noises. The machine learning systems, algorithms or techniques used to predict such noises may be trained using emitted sound pressure levels observed during prior operations of aerial vehicles, as well as environmental conditions, operational characteristics of the aerial vehicles or locations of the aerial vehicles during such prior operations. Anti-noises may be identified and generated based on an overall sound profile of the aerial vehicle, or on individual sounds emitted by the aerial vehicle by discrete sources.

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 cancellation 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.

Abstract: An active vibration or noise suppression system is provided that achieves fast convergence of vibration or noise. A sine wave control signal y(n) is constituted by frequency of a vibration or noise source, and an amplitude filter coefficient a(n) and a phase filter coefficient ?(n) as an adaptive filter coefficient. The sine wave control signal y(n) is expressed by a sine wave having an amplitude component and a phase component, and each of an amplitude update term ?a(n+1) and a phase update term ??(n+1) includes a sine wave or cosine wave term having an amplitude component and a phase component. The phase component of the sine wave control signal y(n) is multiplied by a coefficient other than 1, or the phase component of the sine wave or cosine wave term of each of the amplitude update term ?a(n+1) and the phase update term ??(n+1) is multiplied by a coefficient other than 1.

Abstract: An ultrasonic noise cancelation system can include a communication module configured to receive a noise signal detected by a noise detection module, the noise signal representing a noise sound in a listener environment; a noise cancelation module configured to invert the received noise signal thereby creating an inverse noise signal representing an inverse of the noise sound; and a modulator configured to modulate the inverse noise signal onto an ultrasonic carrier to generate an ultrasonic signal.

Abstract: Unlike sound based pressure waves that go everywhere, air turbulence caused by wind is usually a fairly local event. Therefore, in a system that utilizes two or more spatially separated microphones to pick up sound signals (e.g., speech), wind noise picked up by one of the microphones often will not be picked up (or at least not to the same extent) by the other microphone(s). Embodiments of methods and apparatuses that utilize this tact and others to effectively detect and suppress wind noise using multiple microphones that are spatially separated are described.

Abstract: In accordance with methods and systems of the present disclosure, a processing circuit may implement at least one of: a feedback filter having a response that generates at least a portion of an anti-noise component from a playback corrected error, the playback corrected error based on a difference between the error microphone signal and a secondary path estimate; and a feedforward filter having a response that generates at least a portion of the anti-noise signal from a reference microphone signal. The processing circuit may also implement a secondary path estimate filter configured to model an electro-acoustic path of a source audio signal and have a response that generates a secondary path estimate from the source audio signal and a secondary path estimate performance monitor for monitoring performance of the secondary path estimate filter in modeling the electro-acoustic path.

Abstract: From at least a first microphone, first microphone signals are received that represent first sound waves. From at least a second microphone, second microphone signals are received that represent second sound waves. In response to the first microphone signals, first noise in the first sound waves is estimated, and first cancellation signals are output for causing a speaker array to generate first additional sound waves via at least a first acoustic beam for cancelling at least some of the first noise. In response to the second microphone signals, second noise in the second sound waves is estimated, and second cancellation signals are output for causing the speaker array to generate second additional sound waves via at least a second acoustic beam for cancelling at least some of the second noise.

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.

Abstract: A full-duplex RF communication system and corresponding methods use digital adaptive filters for interference cancellation. As provided, the techniques allow full-duplex radio frequency communication without frequency-, time-, or code-division multiplexing and without the use of hardware RF cancellers. Such techniques may be useful for wireless communication, such as cellular communication, radio communication, broadcasting, short-range point-to-point communication, wireless sensor networks, and wireless computer networks.

Abstract: A canal phone incorporates a transducer within an isolation sound chamber for reproducing sound from an audio source, and a sound-transmission passageway, or ambient sound port, for allowing ambient sounds to enter the isolation sound chamber. The passageway has inner and outer apertures, one oriented towards the ambient noise environment outside of the listener's ear and the other oriented toward the isolated chamber formed by the space between a loudspeaker diaphragm within the canal phone and the tympanum of the listener's ear. The canal phone has a port blocking switch mechanism that selectively opens or closes the aperture of the passageway that is open to the ambient noise. This switch mechanism may also electrically disconnect the transducer and seal either the outer or the inner end of the passageway in different embodiments of the invention.

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.