Active Noise Reduction Circuit Power Optimization
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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 cancellation, and the creation of unwanted noise, in addition to short battery life and unpleasant sound artifacts.
Innovation Solution
The method involves an ANR circuit that alternates between master and slave modes to retrieve settings from external storage or processing devices, configures signal processing topologies for feedback-based, feedforward-based, and pass-through audio functions, and dynamically adjusts filter coefficients and data transfer rates to optimize noise reduction while minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ANR circuit continuously retrieves settings from external storage device, then noise reduction effectiveness is improved, but power consumption increases
Solution Approach 1:
The ANR circuit alternates between master and slave modes in periodic intervals, attempting to retrieve settings from external storage device only during master mode periods. This periodic action reduces continuous power consumption while maintaining noise reduction effectiveness by updating settings when external storage is accessible.
Solution Approach 2:
The system attempts to self-configure by retrieving ANR settings from external storage device when in master mode, reducing reliance on continuous external power supply. The circuit serves itself by autonomously updating its noise reduction parameters when external storage is available, thereby reducing ongoing power consumption.
2Adaptability or versatility
If ANR circuit uses wide frequency range for noise cancellation, then noise reduction coverage is improved, but unwanted noise artifacts increase
Solution Approach 1:
The ANR circuit applies different processing characteristics to different frequency ranges. By configuring signal processing topologies and filter coefficients specifically tailored to particular frequency bands, the system achieves effective noise reduction in targeted ranges while avoiding the generation of unwanted artifacts in other ranges.
Solution Approach 2:
The system dynamically adjusts signal processing topologies and filter coefficients based on detected noise conditions. The ANR circuit can reconfigure its frequency response characteristics in real-time, adapting the width and center frequencies of noise cancellation bands to match actual environmental noise profiles, thereby maintaining effectiveness while minimizing artifacts.
3Adaptability or versatility
If ANR circuit dynamically reconfigures signal processing topology, then adaptability to noise conditions is improved, but device complexity increases
Solution Approach 1:
The ANR circuit employs a reconfigurable architecture where a single set of hardware components can perform multiple signal processing functions. By dynamically routing signals through different pathways and activating/deactivating specific processing stages, the circuit achieves adaptability to various noise conditions without requiring separate dedicated hardware for each function.
Solution Approach 2:
The system pre-configures multiple signal processing topologies and filter coefficient sets in advance, stored in internal memory. When noise conditions change, the circuit quickly switches between pre-prepared configurations rather than calculating new parameters in real-time, thereby achieving adaptability while minimizing the computational complexity and processing delay.
Data Source
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AI summary
Method of enhancing the provision of feedforward-based ANR to both ears of a user of a personal ANR device having a first earpiece and a second earpiece, the method comprising: disposing a first feedforward microphone on the first earpiece; disposing a first acoustic driver within the first earpiece; disposing a second feedforward microphone on the second earpiece; disposing a second acoustic driver within the second earpiece; and employing both first feedforward reference sounds detected by the first feedforward microphone and second feedforward reference sounds detected by the second feedforward microphone in deriving both first feedforward anti-noise sounds to be acoustically output by the first acoustic driver and second feedforward anti-noise sounds to be acoustically output by the second acoustic driver.