ANR Reference Sound Compression for Low-Power Stable Noise Reduction
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Solution Overview
Problem
Existing personal active noise reduction (ANR) devices face issues with high power consumption, limited frequency range, and the generation of unwanted noise, leading to short battery life and unpleasant sound experiences.
Innovation Solution
An ANR circuit employing multiple buffers to configure settings dynamically, including a first and second buffer for normal operation and a third buffer for instability detection, along with a Variable Gain Amplifier (VGA) and digital filters, to manage feedforward and feedback noise compression based on environmental noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ANR devices use high power consumption components to achieve better noise reduction, then noise reduction effectiveness is improved, but battery life deteriorates
Solution Approach 1:
The patent implements dynamic configurability of the ANR circuit, allowing it to adapt its power consumption and performance characteristics based on operating conditions. The circuit can be configured in different modes (e.g., high-performance mode with full power consumption for maximum noise reduction, and power-saving mode with reduced power consumption for extended battery life), enabling the system to dynamically balance between noise reduction effectiveness and battery life duration.
2Adaptability or versatility
If ANR devices process a wide range of audible frequencies to reduce more noise, then noise reduction coverage is improved, but power consumption increases
Solution Approach 1:
The patent enables dynamic configuration of the frequency processing range in the ANR circuit. The circuit can be programmed to process only the frequency ranges that are most effective for noise reduction in current environmental conditions, rather than continuously processing the entire audible spectrum. This dynamic adaptation allows the system to expand frequency range coverage when needed while conserving power during normal operation.
Solution Approach 2:
The patent implements the ability to change operational parameters of the ANR circuit, including sampling rates, filter characteristics, and processing bandwidth, based on the actual noise environment. By dynamically adjusting these parameters, the system can expand its frequency range coverage to match the characteristics of environmental noise, thereby improving noise reduction coverage without unnecessarily consuming power across the entire frequency spectrum.
3Reliability
If ANR devices increase processing gain to reduce noise more effectively, then noise reduction performance is improved, but unwanted noise generation increases
Solution Approach 1:
The patent implements feedback mechanisms that monitor the output of the ANR circuit and detect instances of instability or unwanted noise generation. When such conditions are detected, the system automatically adjusts the processing gain and other parameters to eliminate the harmful effects. This closed-loop feedback control allows the system to maintain high noise reduction performance while preventing the generation of unwanted noise artifacts.
Solution Approach 2:
The patent incorporates failsafe ANR settings that are pre-configured to prevent instability and unwanted noise generation. These failsafe settings act as a protective mechanism that automatically engages when the system detects conditions that could lead to harmful noise artifacts, thereby cushioning against the potential generation of unwanted noise before it occurs.
4Adaptability or versatility
If ANR devices implement complex dynamic configuration to adapt to different environments, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal configuration mechanism that allows a single ANR circuit design to perform multiple functions and adapt to various environmental conditions. By using programmable components and standardized configuration interfaces, the system achieves high environmental adaptability without proportionally increasing physical complexity. The same hardware infrastructure supports multiple operating modes and adaptation strategies.
Solution Approach 2:
The patent achieves environmental adaptability primarily through software-based parameter changes rather than hardware modifications. The ANR circuit can be reconfigured by changing digital parameters such as filter coefficients, sampling rates, and processing algorithms, allowing the system to adapt to different environments without adding physical complexity to the circuit architecture.
Data Source
AI summary
Apparatus and method of an ANR circuit providing both feedforward-based and feedback-based ANR, possibly of a personal ANR device, compressing both feedforward and feedback reference sounds detected by feedforward and feedback microphones, respectively, in response to the acoustic energy of the feedforward reference noise sound reaching a predetermined level.