Noise-Cancellation Filter Weighting for Actuator Protection
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Solution Overview
Problem
Noise-cancellation systems in predefined volumes, such as vehicle cabins, have limited control over the error signal and are ill-suited for tailored noise-cancellation due to their inability to effectively manage the error signal itself.
Innovation Solution
A noise-cancellation system employing a performance cost filter and an actuator effort cost filter, which allows for greater configurability and control by weighting the error signal and noise-cancellation signal with performance and actuator effort cost functions, respectively, to minimize residual noise and prevent overdriving of actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional noise-cancellation systems are used in predefined volumes, then the system structure is simple, but the control over error signal is limited and tailoring capability is poor
Solution Approach 1:
The error signal processing is segmented into multiple frequency bands using bandpass filters, allowing independent control and tailoring of noise cancellation in different frequency ranges. This enables customized noise suppression characteristics without requiring complete system redesign.
Solution Approach 2:
The system employs adaptive filters with dynamically adjustable coefficients that can be tuned to optimize noise cancellation performance for specific noise profiles and listening positions. The weighting functions dynamically adjust the emphasis on different frequency components based on desired cancellation characteristics.
2Object-affected harmful factors
If aggressive noise cancellation is applied, then noise reduction performance improves, but actuator overdriving risk increases
Solution Approach 1:
The system applies partial action by using weighting functions that selectively emphasize frequency bands where noise cancellation is most needed, rather than uniformly aggressive cancellation across all frequencies. This achieves effective noise reduction while keeping actuator demands within safe operating limits.
Solution Approach 2:
The weighting functions modify the amplitude parameters of the error signal across different frequency bands, allowing the system to adapt the cancellation intensity to match both noise characteristics and actuator capabilities, preventing overdriving while maintaining effectiveness.
3Adaptability or versatility
If uniform noise cancellation is applied across all frequencies, then implementation is simple, but specific frequency tailoring is not achieved
Solution Approach 1:
The system implements local quality by applying different weighting functions to different frequency bands, allowing each frequency range to have customized cancellation characteristics. This enables precise control over which frequencies are suppressed and to what extent, tailored to specific noise sources and listener preferences.
Data Source
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AI summary
A noise-cancellation system, including: a noise-cancellation filter configured to generate a noise-cancellation signal; an actuator configured to receive the noise-cancellation signal and to transduce a noise-cancellation audio signal based on the noise-cancellation signal, the noise-cancellation audio signal destructively interfering with an undesired noise in a noise-cancellation zone in a predefined volume; an error sensor configured to output an error sensor signal, the error sensor signal being representative of residual undesired noise in the noise-cancellation zone; a performance cost filter configured to receive and filter the error sensor signal and to output a performance cost filter signal, the performance cost filter signal being representative of the error sensor signal as weighted by a performance cost function; and an adjustment module configured to receive the performance cost filter signal and to adjust the noise-cancellation filter such that the noise-cancellation audio signal minimizes the performance cost filter signal.