Abstract: Inductively coupled battery charging systems and methods are provided. Transmit circuitry can include a transmit coil operatively part of a transmit resonant circuit exhibiting resonance at a transmit resonant frequency and an unloaded Q value of at least about 20. Transmit coil can generate a magnetic field at about the transmit resonant frequency. Rechargeable battery assembly can include a receive coil configured to receive inductively coupled current, and circuitry configured to rectify the current and communicate charging power to a storage cell. Receive coil can be part of a receive resonant circuit that exhibits resonance at about the transmit resonant frequency. Transmit circuitry can be configured to regulate alternating current produced in the transmit coil based on current flowing in the transmit resonant circuit and/or maintain the magnetic field at about the transmit resonant frequency by maintaining about a ninety degree phase shift between a square wave input and output.

Abstract: Inductively coupled battery charging systems and methods are provided. Transmit circuitry can include a transmit coil operatively part of a transmit resonant circuit that exhibits resonance at a transmit resonant frequency and an unloaded Q value of at least about 20. Transmit coil can generate a magnetic field at about the transmit resonant frequency. Rechargeable battery assembly can include a receive coil configured to receive inductively coupled current, and circuitry configured to rectify the current and communicate charging power to a storage cell. Receive coil can be part of a receive resonant circuit that exhibits resonance at about the transmit resonant frequency and an unloaded Q value of at least about 10. Transmit circuitry can include multiple transmit coils and can selectively discontinue production of alternating current in the coils generating fields that are not most strongly coupled to the receive coil.

Abstract: Inductively coupled battery charging systems and methods are provided. Transmit circuitry can include a transmit coil operatively part of a transmit resonant circuit that exhibits resonance at a transmit resonant frequency and an unloaded Q value of at least about 20. Transmit coil can generate a magnetic field at about the transmit resonant frequency. Rechargeable battery assembly can include a receive coil configured to receive inductively coupled current, and circuitry configured to rectify the current and communicate charging power to a storage cell. Receive coil can be part of a receive resonant circuit that exhibits resonance at about the transmit resonant frequency. Transmit circuitry can be configured to detect the rechargeable battery assembly by monitoring a load on the transmit coil.

Abstract: Rechargeable battery assemblies and methods of constructing rechargeable battery assemblies are provided. Rechargeable battery assemblies can include a storage cell and receive circuitry comprising a receive coil operatively connected to receive control circuitry, the receive coil configured to receive inductively coupled current, the receive control circuitry configured to rectify the current and communicate charging power to the storage cell, the coil wound around a shield/core comprising magnetically permeable material, and the shield/core disposed around the storage cell.

Abstract: Systems and methods for maintaining a drive signal to a resonant circuit at a resonant frequency are provided. A system for maintaining a drive signal to a resonant circuit at a resonant frequency can include: an oscillator configured to provide an output to a phase comparator and a drive circuit, the drive circuit configured to provide a drive signal to a resonant circuit; a phase detector configured to receive a filtered version of the drive signal from the resonant circuit and provide a phase-indicating signal to the phase comparator; and the phase comparator, wherein the phase comparator is configured to provide a signal based on the phase difference between the oscillator output and the phase-indicating signal, wherein the signal from the phase comparator is used to control the frequency of the oscillator such that the phase difference converges to a fixed value.

Abstract: Certain embodiments of the present invention provide a system and method for predicting long-term exposure to a hazardous environment based on a user-controllable measurement interval of short duration. In an embodiment, the system includes an electronic circuit for receiving one or more signals representative of the level of a hazard in an environment using one or more of a hazard level sensor and a direct input jack. The system further includes a processor within the electronic circuit for determining an accumulated dose over a user-controllable measurement interval. In addition, the processor predicts hazardous exposure for a user-settable extended period greater than the user-controllable measurement interval and based on the accumulated dose. The dosimeter also includes a user-operable switch within the electronic circuit and in communication with the processor for controlling the user-controllable measurement interval to be less than a nominal measurement interval.

Abstract: A noise dosimeter with capability to rapidly predict noise exposure over an extended time period based on a measurement of short duration. Either an acoustic or an electrical earphone adapter provides a convenient means to connect the noise dosimeter to an external sound source. A direct input jack operable to receive at least one audio signal provides a signal to an RMS detector, which provides a DC signal to a two-stage amplifier circuit. The outputs of the amplifiers are provided to a processor having multiple A/D channels. The processor calculates accumulated noise doses and drives a display, which in one embodiment includes a panel of light-emitting diodes. In one embodiment, the dosimeter includes functionality for control of external devices such as sound boards.

Abstract: Certain embodiments of the invention may be found in an ultra low power dosimeter assembly. The ultra low power dosimeter assembly may comprise a low power voltage source and a table circuit. The table circuit may be adapted to convert an input voltage to a second voltage level. The second voltage level may correspond to noise dose. The ultra low power dosimeter assembly may also comprise a switch adapted to trigger a control circuit. The control circuit may provide progressive attenuation of an output signal as the second voltage level increases. In certain embodiments, the control circuit may also be adapted to send one or more warning signals to a user of the ultra low power dosimeter. The one or more warning signals may be sent when the control circuit determines the second voltage level has reached one or more pre-determined threshold voltage levels.

Abstract: A microphone capsule for an in-the-ear hearing aid is disclosed. The capsule can include a top plate having first and second spaced openings defining front and rear sound inlets, and a directional microphone cartridge enclosing a diaphragm. The diaphragm is oriented generally perpendicular to the top plate and divides the directional microphone cartridge housing into a front chamber and a rear chamber. A front sound passage communicates between the front sound inlet and the front chamber, and a rear sound passage communicates between the rear sound inlet and the rear chamber. Front and rear acoustic damping resistors having selected resistance values are associated with the front and rear sound passages. The acoustic resistor pair provides a selected time delay, such as about 4 microseconds, between the front and rear sound passages. The use of two acoustic resistors instead of one levels the frequency response, compared to the frequency response provided by a rear acoustic damping resistor alone.

Abstract: A noise dosimeter with capability to rapidly predict noise exposure over an extended time period based on a measurement of short duration. Either an acoustic or an electrical earphone adapter provides a convenient means to connect the noise dosimeter to an external sound source. A direct input jack operable to receive at least one audio signal provides a signal to an RMS detector, which provides a DC signal to a two-stage amplifier circuit. The outputs of the amplifiers are provided to a processor having multiple A/D channels. The processor calculates accumulated noise doses and drives a display, which in one embodiment includes a panel of light-emitting diodes. In one embodiment, the dosimeter includes functionality for control of external devices such as sound boards.

Abstract: Certain embodiments of the invention may be found in an ultra low power dosimeter assembly. The ultra low power dosimeter assembly may include a low power voltage source and a table circuit. The table circuit may be adapted to convert an input voltage to a second voltage level. The second voltage level may correspond to noise dose. The ultra low power dosimeter assembly may also include a switch adapted to trigger a control circuit. The control circuit may provide progressive attenuation of an output signal as the second voltage level increases. In certain embodiments, the control circuit may also be adapted to send one or more warning signals to a user of the ultra low power dosimeter. The one or more warning signals may be sent when the control circuit determines the second voltage level has reached one or more pre-determined threshold voltage levels.

Abstract: Certain embodiments of the invention may be found in a push-in eartip assembly. The push-in eartip assembly may include a mushroom-shaped foam tip. The push-in eartip assembly may also include a hollow tube extending through the center of the mushroom-shaped foam tip. An inner diameter of the hollow tube may be constant and an outer diameter of the hollow tube may be tapered. In certain embodiments, the push-in eartip assembly may further include an adhesive for bonding the mushroom-shaped foam tip to an outer surface of the hollow tube. In certain embodiments, the hollow tube may extend through a center hole in the mushroom-shaped foam tip that extends from the top to the base of the mushroom-shaped foam tip.

Abstract: A directional microphone assembly for a hearing aid, and methods of assembling a directional microphone, are provided. The hearing aid has one or more microphone cartridge(s), and first and second sound passages. Inlets to the sound passages, or the sound passages themselves, are spaced apart such that the shortest distance between them is less than or approximately equal to the length of the microphone cartridge(s). A sound duct and at least one surface of a microphone cartridge may form each sound passage, where the sound duct is mounted with the microphone cartridge. Alternatively, each sound duct may be formed as an integral part of a microphone cartridge.

Abstract: A directional microphone array system generally for hearing aid applications is disclosed. The system may employ a broadside or an endfire array of microphones. In either case, the signals generated by the microphone are added using a plurality of summation points that are connected together via a single signal wire or channel. In the case of the endfire array, all but one of the signals is delayed so that the summation of the signals are in phase. The summation of the signals is then used to generate an output signal for a speaker of a hearing aid or the like.

Abstract: A method and system for providing low-noise, high-fidelity wireless Bluetooth earphones with control operation either at the earphone or the player that operate to control the volume and other functionality from either location in a seamless manner and provide probe volume control display regardless of which location is used.

Abstract: The present invention relates to systems and methods for protecting acoustic devices. In particular embodiments, barriers are useful for preventing a variety of solid, liquid, and vapor contaminants from modifiying or damaging the performance of acoustic transducers, while at the same time providing essentially an acoustically transparent passage of sound.

Abstract: Systems and methods for wireless communication can include a first unit configured to synchronously transmit a first digital audio packet redundantly in at least a first dedicated slot and a second dedicated slot over a time period, and a second unit configured to receive wireless transmissions from the first unit. In certain embodiments, the second unit does not listen for a transmission in the second dedicated slot if the first digital audio packet is received in the first dedicated slot. In certain embodiments, the units are encoded with a group code that identifies group members, such that the units only receive data packets transmitted by group members with the same group code.

Abstract: A programmable digital hearing aid circuit and method for operating and programming same are disclosed. The device provides a flexible means to compensate for undesirable frequency response distortion normally due to the electro-acoustical characteristics of the microphone, receiver, and sound coupling mechanisms employed in hearing aid design. Parameters of the programmable hearing aid circuit may also be set to tailor the hearing aid response characteristics for the frequency-dependent hearing loss of an individual hearing aid user. The device is intended to make available a significant improvement in audio fidelity to users of hearing aid devices.

Abstract: Certain embodiments of the present invention provide a system and method for predicting long-term exposure to a hazardous environment based on a user-controllable measurement interval of short duration. In an embodiment, the system includes an electronic circuit for receiving one or more signals representative of the level of a hazard in an environment using one or more of a hazard level sensor and a direct input jack. The system further includes a processor within the electronic circuit for determining an accumulated dose over a user-controllable measurement interval. In addition, the processor predicts hazardous exposure for a user-settable extended period greater than the user-controllable measurement interval and based on the accumulated dose. The dosimeter also includes a user-operable switch within the electronic circuit and in communication with the processor for controlling the user-controllable measurement interval to be less than a nominal measurement interval.

Abstract: A hearing aid apparatus is disclosed that employs both an omnidirectional microphone and at least one directional microphone of at least the first order. The electrical signals output from the directional microphone are supplied to an equalization amplifier which at least partially equalizes the amplitude of the low frequency electrical signal components of the electrical signal with the amplitude of the mid and high frequency electrical signal components of the electrical signals of the directional microphone. A switching circuit accepts the signals output from both the omnidirectional microphone and the directional microphone. The switching circuit connects the signal from the omnidirectional microphone to an input of a hearing aid amplifier when the switching circuit is in a first switching state, and connects the output of the equalization circuit to the hearing aid amplifier input when the switching circuit is in a second switching state.