Hearing Aid Telecoil Interference Mitigation via Signal Estimation
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Solution Overview
Problem
Hearing aids with telecoils and RF transceivers experience interference due to current transients generated during RF transceiver operation, which disrupts the audio signal from magnetically sensitive transducers, preventing simultaneous use of telecoils and RF transmission without turning off the RF transceiver.
Innovation Solution
The processor estimates and substitutes the audio signal during current transients using pre- and post-transient samples, employing techniques like Linear Predictive Coding and windowing to minimize interference, allowing for simultaneous telecoil use and RF transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the RF transceiver is turned on for wireless communication, then wireless functionality is enabled, but current transients generate magnetic field gradients that interfere with telecoil signal output
Solution Approach 1:
The system performs preliminary actions by storing undisturbed telecoil signal samples before RF transmission begins and preparing estimated signal values in advance. This allows the system to have replacement signal data ready before the interference occurs, enabling seamless substitution without actual disruption to the audio output.
Solution Approach 2:
The processor acts as an intermediary by generating estimated telecoil signal values based on previously stored undisturbed samples. This estimated signal serves as a mediator that replaces the actual disturbed signal during RF transmission, allowing both functions to coexist without direct interference affecting the final output.
2Reliability
If the RF transceiver is turned off to prevent interference, then telecoil signal quality is maintained, but wireless communication and remote control functionality are lost
Solution Approach 1:
The system performs preliminary action by storing undisturbed telecoil signal samples before RF transmission begins. This pre-stored data serves as the basis for generating estimated signals that replace the disturbed audio output, allowing wireless communication to proceed without sacrificing telecoil signal quality.
Solution Approach 2:
The system creates a copy of the undisturbed telecoil signal by storing samples before RF transmission. This copied signal is then used to generate estimated values that replace the actual disturbed signal, effectively replicating the desired audio output without being affected by the RF interference.
3Use of energy by moving object
If current transients are allowed to flow during RF transceiver operation, then power consumption is manageable, but magnetic field gradients disturb the telecoil signal
Solution Approach 1:
The system converts the harmful effect of current transients into a beneficial process by using the known characteristics of signal degradation to generate accurate estimated values. Instead of trying to eliminate the current transients, the system accepts them and compensates for their effect by substituting the disturbed signal with pre-calculated estimated values based on undisturbed samples.
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
This method effectively reduces interference, enabling the hearing aid to use telecoils and RF transmission concurrently without disrupting the audio signal, improving user experience by maintaining clear audio output during RF transceiver operation.
Implementation Method 1
A telecoil consists of a metal core (or rod) around which ultra-fine wire is coiled. Telecoils generate an electrical signal in response to a varying magnetic field.
Implementation Method 2
turning the RF transceiver on or off generates a large current transient in the hearing aid circuitry, and during the duration of the current transient, a varying magnetic field with large magnetic field gradients is generated
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
A hearing aid is provided comprising a magnetically sensitive transducer (11) for conversion of a varying magnetic field into an audio signal, a processor (16) configured to generate a hearing loss compensated output signal based on the audio signal, an output transducer (20) for conversion of the hearing loss compensated output signal to an auditory output signal that can be received by the human auditory system, an RF transceiver (22) for wireless communication, and a communication controller (24) that is configured to turn the RF transceiver (22) on and off, and wherein, the processor (16) is further configured to generate, within a time period (40) comprising the event that the RF transceiver (22) changes state between on and off, the hearing loss compensated output signal based on an estimate of the audio signal, and wherein the estimate is based on a part of the audio signal input to the processor (16) outside the time period (40), whereby possible interference from RF-transmission is removed from the audio signal.