ANR Signal Processing Topology for Power and Noise Control
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Solution Overview
Problem
Existing personal active noise reduction (ANR) devices face issues with high power consumption, limited frequency ranges for noise reduction, and the generation of unpleasant noise sounds, often creating more noise than they reduce.
Innovation Solution
A personal ANR device incorporating a signal processing topology with feedback-based, feedforward-based, and pass-through audio pathways, where feedback anti-noise sounds, feedforward anti-noise sounds, and modified pass-through audio sounds are combined and output by an acoustic driver, with features like selectable combination points and filter blocks for frequency splitting, and a compression controller to prevent clipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional ANR signal processing is used, then noise reduction is provided, but power consumption is high
Solution Approach 1:
The patent segments the ANR signal processing into three distinct parallel pathways: feedback ANR pathway, feedforward ANR pathway, and pass-through audio pathway. Each pathway processes specific signal components independently, allowing selective activation and optimization of power consumption for each function while maintaining overall noise reduction effectiveness.
Solution Approach 2:
The patent implements dynamic signal routing that adapts the processing pathways based on operational conditions. The system can selectively activate or deactivate specific pathways (feedback, feedforward, pass-through) depending on the noise environment and user needs, enabling power consumption to be dynamically adjusted while maintaining effective noise reduction when required.
2Adaptability or versatility
If traditional ANR processing is used, then some noise reduction is achieved, but the frequency range is narrow
Solution Approach 1:
The patent divides the frequency processing into specialized pathways: the feedforward pathway handles low-frequency noise reduction, while the feedback pathway handles higher frequency noise. This segmentation allows each pathway to be optimized for specific frequency ranges, expanding the overall effective frequency range without requiring a single complex processing system.
Solution Approach 2:
The patent creates a multi-functional signal processing system where the same ANR device can simultaneously provide feedback ANR, feedforward ANR, and pass-through audio functionality. This universal design allows the device to adapt to different noise environments and user preferences, effectively handling a broad frequency range through multiple specialized functions working together.
3Reliability
If aggressive ANR processing is used, then noise reduction is enhanced, but unpleasant noise sounds are generated
Solution Approach 1:
The patent extracts the pass-through audio pathway as a separate, independent function from the ANR processing. This allows the system to remove or bypass the aggressive ANR processing for audio signals that should pass through unchanged, preventing the generation of unpleasant noise sounds while maintaining effective noise reduction for environmental sounds through the dedicated feedback and feedforward pathways.
Solution Approach 2:
The patent applies different processing qualities to different signal types: aggressive ANR processing is applied to environmental noise signals in the feedback and feedforward pathways, while pass-through audio signals receive minimal or no processing. This local differentiation ensures effective noise reduction where needed while preserving audio quality and avoiding unpleasant artifacts in the audio pathway.
4Reliability
If multiple ANR pathways are combined, then noise reduction is improved, but device complexity increases
Solution Approach 1:
The patent segments the combined ANR system into three distinct, parallel processing pathways with clear functional separation. Each pathway (feedback ANR, feedforward ANR, pass-through audio) is independently structured and processed, making the overall complex system manageable through modular design. This segmentation allows the complexity to be distributed and controlled while achieving superior noise reduction through the combination of multiple pathways.
Data Source
AI summary
An ANR circuit, possibly of a personal ANR device, incorporates an signal processing topology to support the provision of feedback-based ANR, feedforward-based ANR and pass-through audio in which the topology incorporates a branch in which feedback anti-noise sounds are generated from feedback reference sounds received from a feedback microphone, a branch in which feedforward anti-noise sounds are generated from feedforward reference sounds, and a branch in which modified pass-through audio sounds are generated from pass-through audio sounds received from an audio source, wherein these three branches are combined to combine the generated sounds of each branch into a single output by which an acoustic driver, possibly of the personal ANR device, is driven.