Hearing Instrument Probe-Stop Filtering for In-Ear Feedback Estimation

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Solution Overview

Problem

Existing methods for determining acoustic characteristics of hearing instruments, such as feedback path characteristics, disrupt normal operation and provide biased results due to correlation with external signals, necessitating improved open-loop identification techniques.

Innovation Solution

A method involving the emission of an acoustic probe signal, filtering to attenuate probe signal components, and analyzing the input audio signal to determine characteristics without disrupting normal operation, using a probe-stop filter to selectively attenuate probe signal components, allowing for high-quality, unbiased feedback path estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If open-loop measurements are performed to identify feedback path characteristics, then measurement precision is improved, but normal operation of the hearing instrument is disrupted

Engineering Contradiction:

Improvefeedback path identification precisionVSAvoidnormal operation continuity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent segments the audio signal processing into separate components: the probe signal path for measurement and the normal audio signal path for operation. By filtering out only the probe signal components from the microphone input while preserving other audio signals, the system performs measurements without disrupting normal hearing instrument function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a probe signal as an intermediary test signal that is emitted by the output transducer and selectively filtered from the microphone input. This intermediary signal enables feedback path identification without requiring interruption of normal operation, as it can be superimposed on and separated from the normal audio signal stream.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If probe signal emission is performed at higher levels for better signal-to-noise ratio, then measurement precision is improved, but user comfort deteriorates due to masking of environmental sounds

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidmasking of environmental sounds

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs dynamic adjustment of the probe signal level based on environmental conditions and user requirements. The system can adaptively control the probe signal amplitude to maintain adequate signal-to-noise ratio for measurement while preventing excessive levels that would mask environmental sounds, thus dynamically optimizing both measurement quality and user comfort.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If the hearing instrument is positioned in the ear canal for in situ measurements, then adaptability is improved, but measurement time increases due to fitting procedure requirements

Engineering Contradiction:

Improvein situ measurement capabilityVSAvoidfitting procedure time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent enables continuous feedback path identification during normal hearing instrument operation. By allowing probe signal emission and processing to occur concurrently with normal hearing aid function, the system eliminates the need for separate measurement sessions, thereby maintaining adaptability for in situ measurements while significantly reducing the time required for fitting procedures.

Inventive Principle:

Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate determination of hearing instrument characteristics without disturbing the user, reducing the risk of missing important environmental sounds during fitting sessions, and facilitating extended, low-level probe signal emission for precise feedback path estimation.

Implementation Method 1

emitting an acoustic probe signal by the output transducer

Methodology Applied

Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

filtering the received input audio signal to selectively attenuate one or more signal components corresponding to the acoustic probe signal

Methodology Applied

Scientific EffectFrequency selective filtering: Filter (electronic)

Data Source

PatentUS20260012735A1Determining an acoustic characteristic of a hearing instrument

Publication Date: 2026.01.08 GN HEARING AS

AI summary

A method for determining a characteristic of a hearing instrument is disclosed. The hearing instrument includes at least one input transducer operable to provide an input audio signal responsive to sensing sound in the environment of the hearing instrument, a signal processing unit and at least one output transducer. The method includes: emitting an acoustic probe signal by the output transducer, receiving an input audio signal from the microphone, analyzing the received input audio signal to determine the characteristic of the hearing instrument from an input transducer response to the emitted acoustic probe signal, wherein the method comprises filtering the received input audio signal to selectively attenuate one or more signal components corresponding to the acoustic probe signal and wherein emitting the acoustic probe signal comprises emitting a combined acoustic output signal comprising the acoustic probe signal and an acoustic hearing instrument signal obtained from the filtered input audio signal.