Active Noise Cancellation Filter System with Adjustable Parameters

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Solution Overview

Problem

Classical active noise cancellation systems with fixed analog filter-based control law transfer functions are inflexible, unable to adjust for production variations, electro-acoustic design changes, or dynamic noise conditions, and are not suitable for integration within integrated circuits due to high component counts.

Innovation Solution

Implementing a system with multiple filters, each operable over different frequency ranges and having adjustable parameters such as amplitude and bandwidth, allowing dynamic adjustment of the control law transfer function to optimize noise cancellation, using parametric filters and a dynamic adjustment controller.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed analog filter is used to realise the control law transfer function, then the implementation is simple with fixed components, but the system cannot adjust for production variations, electro-acoustic design changes, or dynamic noise conditions

Engineering Contradiction:

Improveadjustability of control law transfer functionVSAvoidcomponent count and adjustment mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the Dynamics principle by transforming the fixed analog filter into an adjustable filter system. The filter parameters (such as cutoff frequency, Q-factor, and gain) are made dynamically可调 through digital control interfaces, allowing the control law transfer function to be adapted to different production variations, electro-acoustic designs, and noise conditions without changing the physical hardware architecture.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implementsParameter changes by allowing digital modification of filter parameters including cutoff frequency, bandwidth, and gain. These parameters can be programmatically adjusted to optimize noise cancellation performance across different operating conditions and device variations, resolving the contradiction between fixed simplicity and adaptive performance.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a fixed analog filter is used, then the design is straightforward, but it does not allow easy accommodation of a range of electro-acoustic designs

Engineering Contradiction:

Improvecompatibility with different electro-acoustic designsVSAvoiddesign flexibility

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent appliesUniversality by designing a filter system that can serve multiple electro-acoustic designs through digital parameter configuration. A single hardware platform can accommodate various speaker and microphone configurations by programmatically adjusting the filter characteristics, eliminating the need for separate fixed-filter designs for each electro-acoustic variant.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If a fixed analog filter is used, then the system is stable, but it cannot provide dynamic adjustment of the control law for optimised noise cancellation

Engineering Contradiction:

Improvedynamic adjustment capabilityVSAvoidsystem stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implementsFeedback mechanisms that allow the system to sense noise characteristics and dynamically adjust filter parameters accordingly. This closed-loop approach maintains system stability through controlled adaptation, enabling optimized noise cancellation across varying noise fields while preserving overall system reliability through gradual, monitored parameter changes.

Inventive Principle:

Principle #23Feedback

4Adaptability or versatility

If multiple adjustable filters are used to realise the control law transfer function, then the system becomes flexible and adaptable, but the component count increases and integration becomes more difficult

Engineering Contradiction:

Improveflexibility of control law realisationVSAvoidnumber of filters and adjustment mechanisms

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent appliesMerging by integrating multiple filter functions into a unified digital signal processing architecture. Rather than using separate physical filters for each frequency range, the system combines multiple adjustable filter stages into a single integrated circuit or digital processor, reducing external component count while maintaining the flexibility of multiple adjustable parameters for optimized noise cancellation.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9818394B2Realisation of controller transfer function for active noise cancellation

Publication Date: 2017.11.14 AMPHENOL PHITEK LTD

AI summary

An apparatus for realizing an active noise cancellation control law transfer function between a sensing microphone and a speaker. The apparatus includes a multiplicity of filters. Each filter is operable over a different frequency range. At least one filter has an adjustable parameter whereby the filter can be adjusted such that the filters cumulatively realize a required control law transfer function. The adjustable parameter may in one embodiment be the amplitude. In other embodiments, it may be other parameters.