Hearing Device Feedback Detection Using Magnitude Phase Analysis
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Solution Overview
Problem
Modern hearing aids face challenges in effectively detecting and managing feedback, particularly in accurately estimating the open loop magnitude and phase functions, which are crucial for minimizing acoustic feedback and ensuring optimal performance.
Innovation Solution
The proposed method involves a hearing device with a magnitude and phase analysis unit that repeatedly determines the loop magnitude and phase of the electric input signal based on the feedback loop delay, using a frequency-dependent analysis to provide feedback detection signals and estimate the complex loop transfer function, allowing for adaptive feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional feedback detection methods are used in hearing aids, then the feedback control system can operate, but the accuracy of estimating open loop magnitude and phase functions is insufficient
Solution Approach 1:
The patent changes the parameters used for feedback detection from conventional methods to specifically measuring open loop magnitude and phase functions. By using magnitude measurement circuits and phase measurement circuits to directly measure these parameters, the system achieves more accurate feedback detection and improved reliability in feedback control performance.
2Measurement precision
If the feedback detection system measures multiple parameters (magnitude and phase), then the feedback estimation becomes more accurate, but the device complexity increases
Solution Approach 1:
The patent segments the feedback detection system into specialized functional modules: magnitude measurement circuits for measuring open loop magnitude, phase measurement circuits for measuring open loop phase, and a processor for combining these measurements. This segmentation allows each module to focus on a specific measurement task, improving overall estimation accuracy while organizing complexity into manageable, dedicated components.
Solution Approach 2:
The processor serves multiple functions by receiving both magnitude and phase measurements from separate circuits and combining them to estimate the complex loop transfer function. This multi-functionality reduces the need for separate dedicated processing units for each measurement type, thereby managing device complexity while maintaining high measurement precision.
3Reliability
If the feedback control system operates continuously to minimize acoustic feedback, then feedback performance is maintained, but the processing requirements and energy consumption increase
Solution Approach 1:
The patent replaces complex continuous signal processing with dedicated measurement circuits that directly measure magnitude and phase parameters. By using specialized hardware circuits instead of continuous computational processing, the system maintains reliable feedback suppression while significantly reducing processing requirements and energy consumption.
Data Source
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AI summary
A hearing device, e.g. a hearing aid, comprises a forward path for processing an electric signal representing sound including a) an input unit for receiving or providing an electric input signal representing sound, b) a signal processing unit, c) an output transducer for generating stimuli perceivable as sound to a user, d) a feedback detection unit configured to detect feedback or evaluate a risk of feedback via an acoustic or mechanical or electrical feedback path from said output transducer to said input unit and comprising d1) a magnitude and phase analysis unit for repeatedly determining magnitude, Mag, and phase, Phase, and loop phase difference, LpPhaseDiff, of said electric input signal and optionally further parameters based thereon, and d2) a feedback conditions and detection unit configured to check criteria for magnitude and phase feedback condition, respectively, based on said values, and to provide a feedback detection signal indicative of feedback or a risk of feedback.