Abstract: A simplified algorithm for digital signal interpolation and a novel architecture to implement the algorithm in an integrated circuit (“IC”) with significant space constraints are presented. According to embodiments of the present invention, the interpolator is divided into two parts. The first part of the interpolator increases the sample rate by a factor of two and smoothes the signal using a half-band Infinite Impulse Response (“IIR”) filter. The second part of the interpolator increases the sample rate of the signal by a factor of thirty-two using a zero-order-hold (“ZOH”) circuit. In one embodiment, the half-band IIR filter is implemented using an all-pass lattice structure to minimize quantization effects. The lattice coefficients are chosen such that the structure can achieve all filter design requirements, yet is capable of being implemented with a small number of shifters and adders, and no multipliers.

Abstract: A system for detecting a low battery power condition and providing an audible warning of such a condition to a user of an electronic device such as a hearing aid is disclosed. In one embodiment, the battery output voltage is monitored and compared to a first threshold voltage at specified sampling intervals. When a battery output voltage measurement below the first threshold voltage is detected, this measurement is verified by a rule specifying that a low battery condition is not deemed to exist unless a predetermined percentage of voltage measurements within a predetermined time interval indicate that the battery output voltage is below the first threshold voltage. If the low battery condition is verified, an audible warning is generated, which is repeated at specified warning intervals. This audible warning affords an opportunity to the user for replacing the batteries in the device before loss of operation or degraded sound quality are experienced.

Abstract: A hearing aid retention and extraction device comprises a retention ring having an outer bonding surface and an inner grasping surface, and an elongate member extending from the retention ring. The retention and extraction device can be incorporated into a hearing device tip and allows both a hearing device and the hearing device tip to be simultaneously removed from an ear canal. When a user pulls on the elongate member, the retention ring cinches around the hearing device and prevents it from becoming separated from the hearing device tip. The cinching action of the retention ring also holds the hearing device in place within the ear canal.

Abstract: In a serial interface for a programmable hearing aid, no address is provided for the data transferred to or read from the hearing aid, rather, for each instruction, the number of data words being transferred pursuant to each instruction and the beginning word are known in the controlled device. In the serial interface, the data is clocked into and out of the hearing aid on a serial data pin by a serial clock. Because no addresses are sent along with the data to the controlled device, the amount of data transferred to the hearing aid is significantly reduced, and no circuitry is required to save the address.

Abstract: A method for fitting a hearing compensation device comprises selecting a plurality of loudness levels for a plurality of frequencies and comparing each loudness level for each frequency for perceived sameness. The loudness levels may then be adjusted as needed to achieve perceived sameness across the frequency spectrum. A gain curve for each frequency is calculated from the selected plurality of loudness levels.

Abstract: A hearing aid retention and extraction device comprises a retention ring having an outer bonding surface and an inner grasping surface, and an elongate member extending from the retention ring. The retention and extraction device can be incorporated into a hearing device tip and allows both a hearing device and the hearing device tip to be simultaneously removed from an ear canal. When a user pulls on the elongate member, the retention ring cinches around the hearing device and prevents it from becoming separated from the hearing device tip. The cinching action of the retention ring also holds the hearing device in place within the ear canal.

Abstract: A hybrid loop filter includes an integrator having an input and an output wherein the output forms an output of the hybrid loop filter, a plurality of transconductance amplifiers having an input and an output wherein each output of the plurality of transconductance amplifiers is coupled to the input of the integrator, a switched capacitor low pass chain having an input and a plurality of branches wherein each of the plurality of branches is coupled to the input of a separate one of said plurality of transconductance amplifiers, and a feedthrough branch having an input and an output wherein the input is coupled to the input of the switched capacitor low pass chain to form an input of said hybrid loop filter, and the output is coupled to the input of a separate one of the plurality of transconductance amplifiers.

Abstract: A self-cleaning cerumen guard includes a thermally activated element. The cerumen guard is mounted on the distal end of a hearing device adjacent to a sound port. The thermally activated element is oriented in a manner which causes it to retract when heated to a first temperature range and extend when cooled to a second temperature range, such that, upon removal of the hearing device from an ear canal, the self-cleaning cerumen guard will automatically remove any accumulated debris from the sound port.

Abstract: A cerumen barrier removable from a retaining ring in a hearing aid shell comprises an endcap disposed in the retaining ring, wherein the endcap has a sound passage with a first opening and a second opening, and the first opening is positioned above a sound tube and the second opening is covered by an oleophobic and hydrophobic screen.

Abstract: A movable cover that pivots over a receiver port in the hearing aid shell forms a cerumen barrier. Alternatively, the cerumen barrier includes both a movable cover that pivots over a receiver port in the hearing aid shell and a deformable grommet and membrane assembly that is disposed over the receiver port.

Abstract: A hearing compensation system for the hearing impaired comprises an input transducer for converting acoustical information at an input to electrical signals at an output, an output transducer for converting electrical signals at an input to acoustical information at an output, a plurality of bandpass filters, each bandpass filter having an input connected to the output of said input transducer, a plurality of AGC circuits, each individual AGC circuit associated with a different one of the bandpass filters and having an input connected to the output of its associated bandpass filter and an output connected to the input of the output transducer. The bandpass filters and AGC circuits may be divided into two processing channels, one for low frequencies and one for high frequencies and may drive separate audio transducers, one configured for maximum efficiency at low frequencies and one configured for maximum efficiency at high frequencies.

Abstract: A hearing compensation system comprises an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof, a differential analog-to-digital converter sampling the electrical signals output from the input transducer at an input thereof and outputting differential signal samples at an output thereof, a digital signal processing circuit having an input connected to the output of the differential analog-to-digital converter and operating on the differential signal samples to form processed differential signal samples at an output thereof, and an output transducer for converting electrical signals at an input thereof to acoustical information at an output thereof, the processed differential signal samples coupled to the input of the output transducer.

Abstract: An analog-to-digital converter comprises a modulator connected to an analog input signal, a decimator connected to the output of the modulator, a normalizer connected to the output of the modulator and forming a digital output signal, and a programmable gain control circuit connected to the output of the normalizer and providing feedback gain control to the modulator and the decimator.

Abstract: In a double-sided pulse width modulator, an amplifier has a first input connected to a first reference potential, a second input, and an output. A first bank of storage elements have a first terminal connected to the second input of the amplifier, and a second terminal. A first bank of switches have an output terminal connected to a second terminal of the storage elements, an input terminal, and a control terminal connectable by a timing gate to an output of the modulator and a polarity control bit for a first value to be input into the input terminals. A feedback storage element is connected in parallel with a first timing switch between the second input of the amplifier and the output of the amplifier. A comparator has a first input connected to a second reference potential, a second input, a timing enable input, and an output. A second bank of storage elements have a first terminal connected to the second input of the comparator, and a second terminal.