Abstract: A method is described herein comprising one or more applications running on at least one processor of a mobile device for providing receiving a mono audio file, receiving a stereo audio file, applying digital signal processing to the mono audio file, wherein the signal processing converts the mono audio file into a processed format suitable for transmission using a first communications protocols, synchronizing transmission of the mono audio file and the stereo audio file, transmitting the mono audio file to at least one remote sensor in the processed format using the first communications protocol, and transmitting the stereo audio file through an audio output of the mobile device using a second communications protocol.

Abstract: A method and a device for equalizing audio signals, where the method includes: obtaining an audio signal (S401); acquiring an echo estimate that is caused by a sound reflection off one or more objects (S403); acquiring correction data based on the audio signal and the echo estimate (S405); and equalizing the audio signal based on the correction data (S407). 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.

Abstract: A method and a device for equalizing audio signals, where the method includes: obtaining an audio signal (S401); acquiring an echo estimate that is caused by a sound reflection off one or more objects (S403); acquiring correction data based on the audio signal and the echo estimate (S405); and equalizing the audio signal based on the correction data (S407). 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.

Abstract: An audio system includes a loudspeaker, a first microphone, an echo canceller, and a second microphone within the loudspeaker enclosure coupled to the loudspeaker. The first microphone provides an environmental acoustic signal to the echo canceller. The second microphone can be a high acoustic overload microphone and be placed in a back cavity of the speaker enclosure. A speaker signal is used to drive the loudspeaker, which may produce non-linear distortions in the acoustic output. The second microphone senses a signal that includes both the linear and non-linear distortions. This sensed signal is used to remove both the linear and the non-linear distortions from the environmental acoustic signal picked up from the first microphone and processed by the echo canceller.

Abstract: 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.

Abstract: 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.

Abstract: A dual backplate microphone is provided that utilizes either an electret condenser or a MEMS condenser configuration and in which an op-amp IC is electrically connected to both backplates and the conductive layer of the diaphragm.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The invention concerns digital processing of analog signals in a telephone set. A signal path runs between a telephone line and the handset of the telephone. A digital signal processor is interconnected within this signal path, together with appropriate analog-to-digital, and digital-to-analog, converters. This approach allows digital processing of the information carried by the signal path. The digital processing facilitates, for example, (1) a high degree of separation of the handset's microphone signal from the received signal, and (2) independent control of volumes of the received signal and sidetone.

Abstract: In an embodiment of the invention, a speaker/microphone peripheral includes a digital-signal-processor (DSP) based acoustic echo canceler and supports a plurality of modes of operation. One mode is a video/telecommunications mode. In this mode, when headphones are inserted or removed, the acoustic echo canceler is reset.