Hearing Instrument Directional Processing with Limited Null Angle
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Solution Overview
Problem
Existing hearing instruments face challenges in achieving robust directional signal processing due to unequal signal levels in input transducers caused by shadowing effects, leading to incomplete interference suppression and signal fluctuations, particularly in specific angular ranges.
Innovation Solution
A method involving complex-valued superposition parameters adapted to form symmetrical or asymmetrical intermediate signals, followed by conversion into real-valued alternative parameters to limit the angle of minimum sensitivity, ensuring efficient suppression of interference within a predetermined angular range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a gain factor is applied to adjust the input signal level for complete attenuation of interference source, then the interference suppression is improved, but the desired signal exhibits strong fluctuations and the system becomes more complex
Solution Approach 1:
The patent changes the parameter representation from complex-valued superposition parameters to real-valued alternative parameters (amplitude and phase). This parameter transformation allows independent control of the interference suppression depth and the angle of minimum sensitivity, enabling stable suppression without causing signal fluctuations in the desired signal.
2Object-affected harmful factors
If complex-valued superposition parameters are used for directional signal processing, then the interference attenuation is improved, but the angular range control becomes difficult
Solution Approach 1:
The patent transforms the complex-valued superposition parameter into two real-valued alternative parameters: amplitude and phase. The phase parameter has a direct monotonic relationship with the angle of minimum sensitivity, enabling intuitive and precise control of the angular range. This parameter change makes it easy to limit the suppression to specific angular ranges while maintaining effective interference attenuation.
3Adaptability or versatility
If time-delayed superposition is used to form directional signals, then the directional processing capability is improved, but the robustness against unequal signal levels deteriorates
Solution Approach 1:
The patent introduces real-valued alternative parameters (amplitude and phase) that decouple the control of interference suppression from the signal level matching. This allows the system to maintain robust directional processing capability through time-delayed superposition while becoming insensitive to unequal signal levels caused by shadowing effects, thereby improving reliability.
Data Source
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AI summary
The invention describes a method for directional signal processing for a hearing instrument (1), wherein a first input signal (E1) and a second input signal (E2) of the hearing instrument (1) are generated from an ambient sound signal (4) by a first input converter (M1) and a second input converter (M2), respectively, wherein a first front intermediate signal (Z1v) and a first rear intermediate signal (Z1h) are each generated from the first input signal (E1) and the second input signal (E2), and wherein, in particular frequency band by frequency band, a first superposition (U1) of the first front intermediate signal (Z1v) and the first rear intermediate signal (Z1h) is formed by means of a complex-valued first superposition parameter (a1), and is adapted based on the first superposition parameter (a1). It is provided that a complex value (a1) resulting from said adaptation of the first superposition (U1) is used.0) of the first superposition parameter (a1) is converted into a first alternative parameter (ap1) and a second alternative parameter (ap2), wherein at least the second alternative parameter (ap2) has at least a semicircular monotonic relationship to an angle (θ) of minimum sensitivity of the first superposition (U1), wherein the angle (θ) of minimum sensitivity is limited to a predetermined angular range (Δθ) by means of a corresponding limitation of the second alternative parameter (ap2), and thereby a limited second alternative parameter (ap2') is formed, and wherein an output signal (out) is generated on the basis of the first alternative parameter (ap1) and the limited second alternative parameter (ap2') as well as on the basis of a superposition of the first input signal (E1) and the second input signal (E2).