Secondary Path Invertibility Metric for ANC Design
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Solution Overview
Problem
There is a lack of a single metric for evaluating the secondary path design in adaptive noise cancellation systems, making it difficult for designers to improve and compare different designs, especially due to the dependency on the physical structure and placement of microphones and speakers, which affects the noise cancellation performance.
Innovation Solution
A new metric and MATLAB toolbox are introduced to measure the invertibility of the secondary path, allowing for improved ANC performance by evaluating the worst-case scenario where the primary path transfer function equals one, and enabling the calculation of a quality factor that simplifies the comparison of different designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the secondary path design is optimized to improve noise cancellation performance, then the noise cancellation gain is improved, but the complexity of evaluating and comparing different designs increases due to the dependency on physical structure and placement
Solution Approach 1:
The patent transforms the complex design evaluation problem into a parameter optimization problem by defining a quality factor Q that characterizes the secondary path transfer function. By changing the evaluation approach from comprehensive physical structure analysis to a single parameter Q optimization, designers can systematically improve noise cancellation performance through parameter tuning while reducing evaluation complexity.
Solution Approach 2:
The patent replaces the mechanical/physical evaluation system (direct measurement and comparison of different physical configurations) with a mathematical model-based system. The quality factor Q serves as a mathematical substitute for complex physical structure evaluation, allowing designers to predict and compare performance without extensive physical prototyping and measurement.
2Measurement precision
If multiple metrics are used to evaluate secondary path design, then the evaluation comprehensiveness is improved, but the ease of comparison between different designs deteriorates
Solution Approach 1:
The patent merges multiple evaluation metrics into a single comprehensive quality factor Q that captures the essential characteristics of the secondary path transfer function. This unified metric combines information about magnitude response, phase response, and other critical factors into one parameter, maintaining evaluation comprehensiveness while enabling straightforward comparison between different designs.
Solution Approach 2:
The quality factor Q serves as a universal metric that can evaluate various aspects of secondary path design across different devices and configurations. This single parameter performs multiple evaluation functions simultaneously, replacing the need for multiple separate metrics and providing a common basis for comparing diverse ANC system designs.
Data Source
AI summary
The present invention provides a system and method encompassing a new metric and MATLAB tool box that phone makers may use to improve the design of the secondary path, in order to improve ANC performance. The metric measures how invertible the secondary path is and then evaluates ANC performance at a worst case scenario where P(z)=1 and W(z) becomes a complete predictor. The invention can be easily extended to a multi-channel ANC system.