Hearing Device Variable Frequency Shift Feedback Suppression
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Solution Overview
Problem
Hearing devices experience feedback whistling due to acoustic feedback, which is exacerbated in open settings and difficult to suppress effectively, especially when there is a high correlation between useful and feedback signals, leading to artifacts such as distortion and amplitude modulation, particularly with tonal signals like music.
Innovation Solution
A method and hearing device that implement a variable first frequency shift and a fixed second frequency shift in the receiver signal, along with an adaptive adaption speed for the feedback suppression filter, to minimize artifacts and stabilize feedback suppression, with the frequency shifts adjusted based on feedback intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency shift is applied to suppress feedback, then feedback suppression is improved, but audible artifacts and distortion increase
Solution Approach 1:
The patent applies dynamic frequency shifting where the frequency shift amount is continuously adjusted based on real-time feedback detection. The system transitions between different frequency shift values (first and second frequency shifts) depending on the feedback level, allowing optimal feedback suppression while minimizing artifacts through adaptive rather than static frequency modification
Solution Approach 2:
The patent changes the frequency parameter dynamically by applying different frequency shift amounts (first frequency shift for strong feedback, second frequency shift for weak feedback) based on the detected feedback level. This parameter adaptation allows the system to suppress feedback effectively while maintaining audio quality by using smaller frequency shifts when feedback is weak
2Reliability
If frequency shift is applied to suppress feedback, then feedback suppression is improved, but response speed and stability are compromised
Solution Approach 1:
The patent implements a feedback mechanism where the frequency shift is continuously adjusted based on real-time feedback detection. The detection unit monitors feedback levels and the frequency shifting unit responds by adjusting the frequency shift amount, creating a closed-loop system that achieves both rapid response and stable feedback suppression through continuous adaptation
3Reliability
If frequency shift is applied to suppress feedback, then feedback suppression is improved, but signal quality and naturalness deteriorate
Solution Approach 1:
The patent applies partial frequency shifting rather than complete frequency transformation. By using smaller frequency shift amounts (second frequency shift) when feedback is weak and only applying larger shifts (first frequency shift) when necessary, the system achieves sufficient feedback suppression while preserving signal quality and naturalness through minimal intervention
Data Source
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AI summary
The invention specifies a method for the operation of a hearing device (1) and a hearing device (1) with at least one receiver (4), which comprises a fixed second frequency shift (18) of an electrical receiver signal (12) supplying the receiver (4) or of a predefinable frequency range of the receiver signal (12) and a variable first frequency shift (19) of the receiver signal (12) or of a predefinable frequency range of the receiver signal (12). The first frequency shift (19) is changed depending on feedback occurring. The invention offers the advantage of a frequency shift, which effectively prevents feedback, wherein however artifacts of the frequency shift are minimized.