Hearing Aid Phase Inversion for Signal-to-Noise Ratio
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Solution Overview
Problem
Composite hearing aid systems face challenges in enhancing the signal-to-noise ratio (SNR) when using wireless receivers, particularly in environments with multiple sound sources, as they often fail to effectively differentiate between desired and unwanted sounds, leading to reduced speech intelligibility for hearing-impaired individuals.
Innovation Solution
A hearing aid system with processors in both ears that can invert the phase of signals from electronic receivers, allowing for improved SNR by presenting desired signals in a dichotic, antiphasic condition while noise is presented in a diotic, homophasic condition, thereby enhancing speech intelligibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireless receivers are used in composite hearing aid systems, then signal-to-noise ratio is improved for distant sound sources, but ability to pick up wanted sounds from other directions is reduced
Solution Approach 1:
The hearing aid system is divided into multiple independent input channels: a first input for receiving a first audio signal (e.g., from a microphone) and a second input for receiving a second audio signal (e.g., from a wireless receiver). Each input can be independently processed and weighted, allowing the system to selectively enhance distant sound sources while maintaining awareness of nearby sounds through the first input channel.
2Measurement precision
If phase inversion is applied to one of the two hearing aids, then signal-to-noise ratio is enhanced through binaural masking level difference, but system complexity increases
Solution Approach 1:
The system dynamically adjusts the phase relationship between the two hearing aids based on the acoustic environment. A processor analyzes the audio signals and automatically inverts the phase of the second hearing aid when beneficial for separating desired sound sources from masking noise, and restores normal phase relationships when not needed, thus providing adaptive SNR enhancement without permanent complexity increase.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a significant improvement in SNR performance, achieving an additional 4-5 dB to 8-9 dB improvement over existing systems, allowing hearing-impaired individuals to better distinguish speech from noise in noisy environments.
Implementation Method 1
means for inverting the phase of the signal received by one of the first or second electronic receivers as compared to the phase of the other one of the first or second electronic receivers
Implementation Method 2
The hearing aid system interfaces with existing hearing aids using the 'T' facility... The system comprises a microphone, an FM radio transmitter connected to the microphone, a receiver unit for receiving a signal from the transmitter unit
Data Source
AI summary
A composite hearing aid system comprises two hearing aids (11, 31) with respective microphones (12, 32) and electronic receivers (17, 37), a microphone (42) and a transmitter (41) adapted to transmit the signal from the microphone (42) to the electronic receivers. At least one of the hearing aids (11, 31) comprises means for inverting the phase of the signal received by the electronic receivers (17, 37). When the phase of the received signal is inverted in one of the hearing aids (11, 31), a release from masking is obtained, and the perceived signal-to-noise ratio is improved. The invention provides a composite hearing aid system, a hearing aid and a method for processing audio signals.