Active Noise Cancellation Wind Handling for Filter Adaptation
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Solution Overview
Problem
Conventional active noise cancellation systems fail to effectively cancel wind noise, as it is not correlated with ambient noise and can result in audible artifacts and incorrect filter adaptation, degrading performance in windy environments.
Innovation Solution
An active noise cancellation system that includes a wind noise detection module to selectively enable and disable adaptation modules, using both feedforward and feedback noise cancellation subsystems, and adjusting gain parameters to suppress wind noise, transitioning between these modes based on wind noise detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional active noise cancellation systems process all reference signals through adaptive filters, then ambient noise is effectively cancelled, but wind noise passes through and degrades performance
Solution Approach 1:
The patent extracts wind noise from the reference signal using a dedicated wind noise detector before the adaptive filter processes the signal. By separating wind noise detection and removal into a distinct stage, the system prevents wind noise from corrupting the adaptive filter's reference signal, thereby maintaining reliable ambient noise cancellation while eliminating wind noise interference.
2Reliability
If adaptive filter continuously adjusts to cancel noise, then noise cancellation is effective, but wind noise causes incorrect filter adaptation
Solution Approach 1:
The patent applies preliminary anti-action by detecting and removing wind noise from the reference signal before it reaches the adaptive filter. The wind noise detector identifies wind noise components and prevents them from corrupting the filter adaptation process, thereby ensuring accurate filter adaptation even in windy conditions.
3Reliability
If system uses both feedforward and feedback noise cancellation, then noise cancellation coverage is improved, but system complexity increases
Solution Approach 1:
The patent merges feedforward and feedback noise cancellation paths into a unified system where both paths process signals through the same adaptive filter structure. The feedforward path processes the reference signal while the feedback path processes the error signal, and both contribute to updating the filter coefficients. This merging approach improves noise cancellation effectiveness while avoiding the complexity of completely separate processing chains.
Data Source
AI summary
Active noise cancellation (ANC) systems and methods include a reference sensor to sense external noise and generate a reference signal, an error sensor to sense noise in a noise cancellation zone and generate an error signal, a feedforward ANC subsystem to receive the reference and error signals and generate a first anti-noise signal to cancel external noise in a noise cancellation zone, a feedback ANC subsystem to receive the error signal and generate a second anti-noise signal to cancel the external noise in the cancellation zone, a wind detector to detect whether wind noise is present in the reference signal and output a wind noise detection status, and wind handler to control adaptation processing of the feedforward ANC subsystem and the feedback ANC subsystem in accordance with the wind noise detection status and mixing of the first and second anti-noise signals to generate an output anti-noise signal.