Lucent Technologies Inc.

Harman International Industries, Inc.

Mwm Acoustics, LLC

At+t Corp.

Other

At&t Bell Laboratories

At&t Information Systems Inc.

Mwm Mobile Products, LLC

Alan Dean Michel

John C Baumhauer, Jr

Jeffrey Phillip McAteer

Christopher Todd Welsh

Larry Allen Marcus

Medford Alan Dyer

Joshua R Barber

Joshua James Barr

Marc Reese

Wayne Allen Weise

Fengyuan Li

Kevin D Willis

James Edward West

Robert E Reinke

David A Brown

Christopher T Welsh

Jason Muhu Chen

Shengbo Li

Po-Hsun Sung

David L Rowley

Eric Williams

Ronald J Kern

William V Powell, Jr

Randal D Wood

Kevin Shank

Simon Liu

Michael Thomas Frank

Larry A Marcus

Brian Adair

A method and a device for equalizing audio signals, where the method includes: obtaining an audio signal (S); acquiring an echo estimate that is caused by a sound reflection off one or more objects (S); acquiring correction data based on the audio signal and the echo estimate (S); and equalizing the audio signal based on the correction data (S). Accordingly, by virtue of the method and the device for equalizing audio signals, equalization can be performed automatically in real time to match an audio signal to a desired reference frequency response with consideration of spatial acoustics, such as indirect echoes.

Method and device for equalizing audio signals

In at least one embodiment, a micro-electro-mechanical systems (MEMS) microphone assembly is provided. The assembly includes an enclosure, a MEMS transducer, and a plurality of substrate layers. The single MEMS transducer is positioned within the enclosure. The plurality of substrate layers support the single MEMS transducer. The plurality of substrate layers define a first transmission mechanism to enable a first side of the single MEMS transducer to receive an audio input signal and a second transmission mechanism to enable a second side of the single MEMS transducer to receive the audio input signal.

Gradient micro-electro-mechanical systems (MEMS) microphone

A transducer assembly utilizing at least two MEMS transducers is provided, the transducer assembly preferably defining either an omnidirectional or directional microphone. In addition to at least first and second MEMS transducers, the assembly includes a signal processing circuit electrically connected to the MEMS transducers, a plurality of terminal pads electrically connected to the signal processing circuit, and a transducer enclosure housing the first and second MEMS transducers. The MEMS transducers may be electrically connected to the signal processing circuit using either wire bonds or a flip-chip design. The signal processing circuit may be comprised of either a discrete circuit or an integrated circuit. The first and second MEMS transducers may be electrically connected in series or in parallel to the signal processing circuit. The first and second MEMS transducers may be acoustically coupled in series or in parallel.

Dual cell MEMS assembly

A passive sound pressure level (SPL) limiter is provided that can be used with audio sources of varying drive levels and headphones or earphones of varying sensitivity. The SPL limiter includes a control circuit and left and right channel limiting circuits, each of which includes a pair of FETS. The SPL limiter may include a balancing circuit that separates the control signal output by the control circuit into left and right channel control signals. The SPL limiter may also include a microphone, for example integrated into an earpiece cable.

Passive sound pressure level limiter with balancing circuit

A passive sound pressure level (SPL) limiter is provided that can be used with audio sources of varying drive levels and headsets, earbuds, etc. of varying sensitivity. The SPL limiter includes a control circuit that includes a rectifier and, in most configurations, a step-up transformer. The SPL limiter also includes a limiting circuit that utilizes a transistor to shunt current from the audio source in proportion to a control signal output by the control circuit. The control circuit may further include a low pass filter, for example an RC filter, and one or more fast limit diode paths. The limiting circuit may further include a feedback network to increase the linear behavior of the limiting circuit.

Passive sound pressure level limiter

A surface mountable package for use with an audio transducer is provided. In addition to the audio transducer, the surface mountable package includes a substrate, a cover, and a transducer support frame mounted within, and attached to, the substrate and cover. The support frame includes one or more cavities that, in combination with the audio transducer, substrate and cover, define the front and rear acoustic cavity volumes.

Transducer package with interior support frame

An omnidirectional electret condenser microphone element with improved low frequency background ambient acoustical noise rejection is provided. The omnidirectional electret condenser microphone element includes a plurality of passageways in acoustic series that couple at least one acoustic aperture of the microphone element to an acoustic cavity formed within the microphone element. At least one of said plurality of passageways is of a predefined size that is determined to provide the desired response roll-off within a predefined frequency range. In at least one preferred configuration, the roll-off resulting from the plurality of passageways is greater than 2.0 dB between 300 and 100 Hz. In at least one alternate preferred configuration, the roll-off resulting from the plurality of passageways is greater than 3.0 dB between 300 and 100 Hz.

Controlled leakage omnidirectional electret condenser microphone element

A surface mountable transducer package is provided, the design of which allows a thin package profile to be achieved. An encapsulation layer bonds to a surface of each of the terminal pads and encapsulates a portion of the transducer and at least a portion of the signal processing IC.

Transducer package with transducer die unsupported by a substrate

A transducer package fabrication process is provided, the completed transducer package achieving a thin package profile. The fabrication process utilizes an encapsulation material to eliminate the need for a transducer support substrate, the encapsulation material isolating the terminal pads from one another while holding the transducer and signal processing IC in position.

Method for fabricating a transducer package with the transducer die unsupported by a substrate

A system and method for RF immunity of an electret condenser microphone. In one embodiment, the microphone comprises a printed wire board, an amplifier, a capacitor. The amplifier and the capacitor are mounted on the printed wire board such that longitudinal axis, i.e., the axis defined by the line between the output pin and the ground pin, of the capacitor is perpendicular to the longitudinal axis of the amplifier. According to one embodiment of the method of the present invention, an electret condenser microphone according to the present invention is provided, and current is provided to the capacitor to result in the creation of a magnetic field about the longitudinal axis of the capacitor. The magnetic field created is positioned such that it does not significantly contribute to the generation of RF current in the amplifier.

System and method for RF immunity of electret condenser microphone

The microphone system for communication devices that comprises an electric circuit comprising two microphone elements connected to a signal flow processor. This processor uses a digital signal processor or comparable analog circuitry to provide a particular electrical time delay (&#x3c4;) to one of the microphone elements (nearest the ear or loudspeaker) and a compatible amplitude gain (Gm) to the other microphone element (nearest the user's mouth) in order to substantially reduce the external acoustic coupling and echo of communication devices in the receive and doubletalk state. Further, this processing system allows the microphone system to reduce the pickup of ambient noise in the send and idle state, while still being sensitive to the user's speech.

Microphone system for communication devices

A telephone handset that includes both a speaker and a secondary flux coil is provided. The secondary flux coil provides improved inductive coupling between the handset and a hearing aid. Due to the wiring configuration of the handset, the speaker and the secondary flux coil can be independently filtered, thus providing means for independently optimizing the performance of both the speaker and the secondary flux coil. Suitable filters include both passive circuits and digital signal processors.

Telephone handset coupling system

A direction finder arrangement advantageously employs a plurality of transducers to derive a plurality of predetermined polar directivity patterns each of which has a predetermined spatial orientation pointing in a predetermined fixed direction relative to each of the other polar directivity patterns. The polar directivity patterns detect a plurality of amplitude values of a propagating wave approaching at different angles relative to the plurality of spatially oriented polar directivity patterns. Then, the detected wave amplitude values are processed to determine an estimate of a direction toward the source of the arriving wave. More specifically, the detected amplitude values are processed to obtain an estimate of the directional orientation of a hypothetical polar directivity pattern pointing toward the source of the arriving wave.

Direction finder

A system and method for echo cancellation in a communication system having a digital echo canceller and an analog echo canceller for analog reduction of cross coupling echo components in an analog output signal when in analog form before digital processing by the digital echo canceller. An analog cancellation signal is generated which is substantially the same as the acoustic coupling echo component in the analog output signal before digital processing by the digital echo canceller. The analog echo cancellation signal is combined with the analog output signal to reduce the cross coupling echo component before digital processing by the digital echo canceller.

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Fishers, IN, United States of America

Alan Dean Michel