Adaptive Feedback Gain Correction in Hearing Aids
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Solution Overview
Problem
Hearing aids face limitations in maximum stable gain due to feedback issues, leading to whistling and distortion, despite advanced adaptive digital feedback cancellation systems, which often result in residual errors causing inadequate gain or excessive amplification.
Innovation Solution
The implementation of an adaptive feedback gain correction method that monitors filter coefficients of the feedback cancellation filter to adjust the gain parameter of the signal processor, accounting for residual errors and maintaining stability by combining this information with prior knowledge of the maximum stable gain limit in each band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive digital feedback cancellation systems are used to suppress feedback, then feedback is reduced and additional gain is achievable, but residual errors remain causing inadequate gain or excessive amplification
Solution Approach 1:
The patent implements a gain correction unit that uses feedback from the adaptive feedback cancellation filter to continuously monitor and correct the gain parameter. The correction is based on the filter coefficients, creating a closed-loop system that adjusts gain dynamically to eliminate residual errors while maintaining feedback suppression.
Solution Approach 2:
The system uses its own internal feedback cancellation filter coefficients to automatically correct its gain parameter without external intervention. The gain correction unit monitors the filter coefficients and self-adjusts the gain to maintain optimal performance, making the system self-correcting.
2Power
If gain is increased to improve amplification, then hearing aid performance is enhanced, but whistling and oscillation occur due to feedback
Solution Approach 1:
The patent applies gain correction based on feedback cancellation filter coefficients before the feedback can cause whistling or oscillation. By monitoring the filter coefficients and adjusting gain proactively, the system prevents harmful oscillations before they occur, allowing higher safe gain levels.
Solution Approach 2:
The system uses feedback from the adaptive feedback cancellation filter to continuously monitor system stability and dynamically adjust the gain parameter. This closed-loop control allows the hearing aid to operate at higher gain levels while automatically preventing whistling and oscillation through real-time feedback correction.
Data Source
AI summary
A hearing aid includes a signal processor, a input transducer electrically connected to the signal processor, a receiver electrically connected to the signal processor, an adaptive feedback cancellation filter configured to suppress feedback from a signal path between the receiver and the input transducer, and a feedback gain correction unit configured for adjusting a gain parameter of the signal processor based at least in part on coefficients of the adaptive feedback cancellation filter. A method of adjusting a gain parameter of a signal processor of a hearing aid includes monitoring filter coefficients of a feedback cancellation filter of the hearing aid, and adjusting the gain parameter of the signal processor in dependence of the monitored filter coefficients.