Hearing Device Active Noise Cancellation Signal Processing
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Solution Overview
Problem
Existing hearing devices that combine active noise cancellation (ANC) and hearing aid circuitry face challenges in attenuating undesired sound signals while preserving desired audio signals, often resulting in reduced audio quality due to the attenuation of both noise and desired sound when ANC is active.
Innovation Solution
A hearing device system that combines a hearing aid circuitry with an active noise cancellation (ANC) system, allowing for the integration of ANC functionality even when the hearing aid is turned off, and includes an audio streaming control unit to enhance signal-to-noise ratio (SNR) by processing both ambient noise and audio signals from streaming devices, using both analogue and digital feed-forward and feed-back ANC methods, and adaptive digital feedback cancellation to adjust filter characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If active noise cancellation is activated to attenuate unwanted sound signals, then noise reduction is improved, but desired audio signals are also attenuated resulting in reduced audio quality
Solution Approach 1:
The patent divides the audio signal processing into separate pathways: one for noise cancellation and one for desired audio signal transmission. The hearing device separates the treatment of different sound components, allowing noise attenuation while preserving wanted sounds through independent signal processing chains.
Solution Approach 2:
The patent applies different processing qualities to different frequency ranges and signal types. Noise cancellation is selectively applied to specific frequency bands where unwanted noise predominates, while desired audio signals in other frequency ranges are preserved with minimal attenuation, creating locally optimized signal quality.
2Use of energy by moving object
If hearing aid circuitry is turned off to save energy, then power consumption is reduced, but noise cancellation functionality is lost
Solution Approach 1:
The hearing device is designed with multi-functionality where the same hardware components can operate in different modes. The device can switch between full hearing aid functionality, noise cancellation only mode, and complete shutdown, allowing energy savings while maintaining essential noise protection capability.
Solution Approach 2:
The patent implements dynamic operational modes that can switch between different states of activity. The noise cancellation system can be activated or deactivated independently of the full hearing aid circuitry, allowing adaptive power management based on environmental noise conditions and user needs.
3Object-affected harmful factors
If ANC attenuates all sound signals to cancel noise, then noise reduction is improved, but audio quality and signal fidelity deteriorate
Solution Approach 1:
The patent segments the audio frequency spectrum into different bands and applies noise cancellation selectively to specific segments where noise is problematic, while leaving other segments intact to preserve overall audio fidelity and signal quality.
Solution Approach 2:
The patent dynamically adjusts the attenuation parameters of the noise cancellation system based on the characteristics of the input signal. When desired audio signals are detected, the attenuation parameters are modified to preserve signal fidelity while maintaining noise reduction effectiveness.
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
The system effectively reduces unwanted noise while maintaining desired audio quality, improving SNR and dynamic range by actively canceling noise even when the hearing aid is off and allowing simultaneous use of audio streaming, thus providing better audible signals to the user.
Implementation Method 1
A hearing device which combines a hearing aid circuitry with an active noise cancellation (ANC) system
Data Source
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AI summary
Disclosed is a hearing device system comprising at least one hearing aid circuitry and at least one active noise cancellation unit, the at least one hearing aid circuitry comprises at least one input transducer adapted to convert a first audio signal to an electric audio signal; a signal processor connected to the at least one input transducer and adapted to process said electric audio signal by at least partially correcting for a hearing loss of a user; an output transducer adapted to generate from at least said processed electric audio signal a sound pressure in an ear canal of the user, whereby the generated sound pressure is at least partially corrected for the hearing loss of the user; the at least one active noise cancellation unit being adapted to provide an active noise cancellation signal adapted to perform active noise cancellation of an acoustical signal entering the ear canal in addition to said generated sound pressure, wherein the hearing device system further comprises a combiner unit adapted to combine the processed electric audio signal with the active noise cancellation signal, to obtain a combined signal and to provide the combined signal to the output transducer.