Binaural Hearing Aid Feedback Suppression With Synchronized Probe Noise
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Solution Overview
Problem
Existing binaural hearing aid systems face challenges in achieving effective adaptive feedback cancellation due to biased estimation of the feedback path, leading to reduced performance and potential howling, especially when the incoming signal is tonal, and current probe noise techniques require low levels to be inaudible, resulting in longer adaptation times and larger variance.
Innovation Solution
A synchronized probe noise approach is implemented in binaural hearing aid systems, using synchronized probe noise generators and a masking model to generate diotic probe noise signals, ensuring high sound quality by optimizing noise levels and frequency shaping, and utilizing a synchronization controller for wireless or wired connection between hearing aids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adaptive feedback cancellation is used in binaural hearing aid systems, then feedback suppression is achieved, but biased estimation of the feedback path occurs leading to reduced performance and potential howling
Solution Approach 1:
The patent introduces an intermediary probe noise signal that is injected into the system to facilitate accurate estimation of the feedback path. This probe noise acts as a mediator between the feedback path and the estimator, enabling unbiased measurement of the feedback characteristics without being corrupted by the incoming speech signal or other disturbances.
Solution Approach 2:
The patent changes the parameters of the probe noise signal dynamically - adjusting its level, frequency content, and temporal characteristics based on the operating conditions. By modifying these parameters, the system optimizes the estimation accuracy across different scenarios while minimizing the impact on the user's auditory experience.
2Object-affected harmful factors
If probe noise techniques are used with low noise levels to be inaudible, then sound quality is maintained, but adaptation times increase and variance increases
Solution Approach 1:
The patent employs periodic injection of probe noise signals at optimized intervals and levels. By using periodic rather than continuous probe noise, the system achieves sufficient estimation accuracy during brief measurement windows while maintaining inaudibility during other periods, thus reducing overall adaptation time without compromising sound quality.
Solution Approach 2:
The system dynamically adjusts the probe noise characteristics (level, frequency, duration) based on real-time conditions such as ambient noise level, current gain settings, and estimated feedback path stability. This dynamic adaptation allows the system to use higher probe noise levels when conditions permit, thereby reducing adaptation time while maintaining inaudibility when necessary.
3Measurement precision
If synchronized probe noise is used in binaural systems, then unbiased feedback path estimation is achieved, but system complexity increases
Solution Approach 1:
The patent merges the probe noise generation and synchronization functions into the existing binaural hearing aid architecture by utilizing the wireless communication link already present for audio streaming and control. The synchronization mechanism leverages the existing timestamping and packet synchronization infrastructure, avoiding the need for separate dedicated synchronization hardware or protocols.
Data Source
AI summary
A binaural hearing aid system comprising a first hearing aid (200) and a second hearing aid, with improved adaptive feedback suppression based on probe noise signals and a method (300) of operating such a binaural hearing aid system.