Adaptive ANC Filter Leakage Control
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Solution Overview
Problem
Conventional active noise cancellation systems in personal listening devices fail to completely cancel noise due to leakage and generate audible artefacts, and they do not allow for selective listening to external noises, leading to degraded performance and user dissatisfaction.
Innovation Solution
An active noise cancellation system with a reference sensor, error sensor, noise cancellation filter, and adaptive gain filter, along with an adaptation engine that adjusts weights and includes leakage control logic to track and adapt to different leakage conditions, and a transparency processing path to allow selective listening to ambient noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional anti-noise filtering systems are used, then noise cancellation is achieved, but residual noise and audible artefacts remain that degrade performance
Solution Approach 1:
The patent implements feedback control by using the error microphone to sense residual noise and feeding this information back to the adaptation engine. The adaptation engine continuously adjusts the noise cancellation filter weights based on this feedback to minimize residual noise and audible artefacts, thereby improving overall noise cancellation performance.
Solution Approach 2:
The patent dynamically changes filter parameters (weights) of the noise cancellation filter based on detected leakage conditions. The adaptation engine adjusts these parameters in real-time to optimize noise cancellation performance for different ear coupling scenarios, transforming the system from static to adaptive parameter adjustment.
2Adaptability or versatility
If fixed noise cancellation filtering is used, then processing is simple, but the system cannot adapt to varying leakage conditions across different users
Solution Approach 1:
The patent transforms the fixed filtering system into a dynamic adaptive system. The adaptation engine continuously monitors leakage conditions through the error microphone and adjusts filter weights in real-time. This dynamic adjustment allows the system to adapt to varying leakage conditions across different users and ear coupling scenarios while maintaining manageable complexity through automated control.
Solution Approach 2:
The system performs self-adjustment through automated adaptation. The adaptation engine autonomously analyzes leakage conditions and modifies filter parameters without requiring manual user input or configuration. This self-service capability enables the system to adapt to individual user characteristics while keeping the user interface simple.
3Adaptability or versatility
If traditional ANC operation is used, then noise cancellation is provided, but users cannot selectively listen to external noises
Solution Approach 1:
The patent implements dynamic mode switching that allows the system to transition between different operational states. Users can selectively enable transparency mode to hear external noises while maintaining noise cancellation for other frequencies. The system dynamically adjusts its signal processing based on user preferences and environmental conditions, providing versatile functionality.
Solution Approach 2:
The patent segments the audio signal processing into different paths: a noise cancellation path for suppressing unwanted noise and a transparency path for preserving external sounds. This segmentation allows users to selectively listen to specific external noises while maintaining overall noise cancellation, adding versatility without overwhelming complexity.
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
Improves noise cancellation performance by adapting to leakage conditions and allowing users to selectively hear ambient noise, reducing artefacts and enhancing user experience across various ear coupling scenarios.
Implementation Method 1
a reference sensor configured to sense ambient noise and generate a corresponding reference signal
Implementation Method 2
an error sensor configured to sense noise in a noise cancellation zone and generate a corresponding error signal
Implementation Method 3
The noise and anti-noise signal cancel each other acoustically
Data Source
Figure 1
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Figure 3A~3D
AI summary
Active noise cancellation systems and methods include a feedforward path configured to receive a reference signal comprising ambient noise and adaptively generate an anti-noise signal to cancel the ambient noise and comprising an adaptive gain component configured to adaptively adjust a gain of the anti-noise signal, and a logic device configured to determine a leakage profile based on the adaptive gain component. The feedforward path includes a feedforward adaptive filter tuned to generate the anti-noise signal corresponding to the reference signal in accordance with the determined leakage profile. The leakage profile is selected from a plurality of stored leakage profiles that are tuned for a corresponding gain, and which corresponds to an ear coupling condition associated with a fit between the active noise cancellation system and a user. An adaptive transparency filter receives the reference signal and generates an ambient inclusion signal for output to a user.