James Newton

Magnetically controllable hearing aid

An apparatus for controlling an adjustable operational parameter of a hearing aid by the use of an external magnetic actuator held in proximity with the hearing aid. The hearing aid has a microphone for generating signals, hearing aid circuitry for processing the signals, an output transducer for transforming the processed signals to a user compatible form, and a single magnetic switch, such as a reed switch, connected to the hearing aid circuitry. The magnetic switch controls the hearing aid circuitry to adjust an adjustable operational parameter, such as volume. In one embodiment the adjustable operational parameter continues to adjust or cycle between a minimum and a maximum as long as the magnetic actuator is maintained in proximity with the magnetic switch. When the magnetic actuator is removed the adjustment ceases. The invention allows precise adjustment and control of an adjustable parameter with minimal effort and movement by the user. The hearing aid circuitry may include a memory to allow a desired setting of the adjustable operational parameter to be saved when the hearing aid is turned off.

Programmable multichannel hearing aid with adaptive filter

A hearing aid is programmable with dual-tone multiple-frequency signals, received through the hearing aid microphone, to adjust operating coefficients of signal conditioning circuitry in the aid. A DTMF receiver filters and detects DTMF tone pairs into digital words provided to a controller for decoding, some of the digital words representing programming instructions and others representing data. In accordance with the instructions, the controller conveys the data to memory operatively associated with a plurality of control ports to the signal conditioning circuitry, with operating coefficients of the conditioning circuitry determined by the contents of the memory.

A Single-chip Hearing Aid With One Volt Switched Capacitor Filters

An integrated circuit has been designed and fabricated in BiCMOS technology which contains three switchedcapacitor fourth-order filters and one continuous-time fourth-order filter, as well as all other circuitry needed for a modern hearing aid. The circuit operates from a single hearing aid battery and functions down to 1.1 Volt, while the switched-capacitor filters are designed to allow power supplies as low as 1.0 Volt.

Strategies for Enhancing the Consonant to Vowel Intensity Ratio With In the Ear Hearing Aids

Numerous investigators have suggested that increasing the consonant to vowel intensity ratio (CVR) may improve speech intelligibility. This investigation was designed to determine the extent to which analog circuits. small enough to fit into in the ear hearing aids, can increase the CVR, and whether CVR enhancement is of benefit to hearing-impaired listeners. Real ear CVRs, calculated from real ear recordings of nonsense syllables, were obtained from eight hearing-impaired listeners. Recordings from each listener were obtained through each of four hearing aid circuits: (1) an adaptive high-pass filter; (2) a faster acting adaptive high-pass filter; (3) the fast-acting adaptive high-pass filter with expansion; and (4) an infinite amplitude clipper. The amount of CVR enhancement was compared to performance of the subjects with a NST speech recognition task. Subjects also ranked the four circuits for amount of consonant emphasis provided. Results indicated that the four hearing aid circuits increased the real ear CVR by 4 to 6 dB, relative to unaided. Aided CVR varied, however, across circuits and between fricative and stop consonants. Performance on the NST recognition task was generally consistent with the amount of CVR increase provided. Rank ordering for consonant emphasis was consistent with aided CVR for stop consonants, but not for fricatives.

Modeling a vented push‐pull hearing‐aid fitting in situ as a feedback control system

For the investigation of acoustic feedback encountered with push‐pull amplification for in‐the‐ear hearing aids, a simulated fitting was considered a feedback control system to include the acoustic leakage from the hearing‐aid receiver traveling back to the microphone. A Gennum WS531 amplifier was connected to an earmold shell made for the right ear of KEMAR. This shell contained a Knowles EK 3024 microphone, a Knowles BK1613 receiver, and a 0.09‐in.‐diam by 0.8‐in.‐long vent hole. Transfer function magnitude and phase were obtained for the microphone, amplifier, receiver, for the open loop while breaking the signal path between microphone and amplifier, and for the closed loop, all with maximum gain before onset of oscillation. The acoustic feedback transfer function was determined by subtracting the forward loop transfer function from the closed loop transfer function. A circuit synthesis program was used to fit the transfer function measurement data into mathematical transfer function expressions. Comp...