Dynamic ANR Circuit Reconfiguration for Noise and Power Trade-Offs
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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 introduction of unwanted noise, leading to short battery life and unpleasant sound experiences.
Innovation Solution
A dynamically configurable ANR circuit that incorporates feedback-based and feedforward-based noise reduction, along with passive noise reduction, using a combination of digital and analog signal processing topologies and filter blocks to optimize noise cancellation and power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active noise reduction is implemented to counter environmental noise, then noise reduction efficacy is improved, but power consumption increases
Solution Approach 1:
The ANR circuit dynamically switches between feedback-based and feedforward-based noise reduction modes, and adjusts the degree of ANR application based on environmental conditions and power availability. This allows the system to optimize the balance between noise reduction efficacy and power consumption in real-time.
Solution Approach 2:
The system changes operational parameters including the type of ANR circuit configuration (feedback vs. feedforward), the degree of ANR application, and the frequency ranges targeted. These parameter changes enable adaptation to different environmental conditions and power states, resolving the contradiction between efficacy and power use.
2Reliability
If the range of audible frequencies for noise reduction is expanded, then noise reduction efficacy is improved, but device complexity increases
Solution Approach 1:
The ANR circuit processes different frequency ranges separately using distinct signal processing paths. By segmenting the frequency spectrum and applying appropriate ANR techniques to each segment, the system achieves broad frequency coverage without requiring a single complex processing chain.
Solution Approach 2:
The circuit design uses universal building blocks (such as programmable filters and switchable signal paths) that can handle multiple frequency ranges and ANR modes. This multi-functionality allows the same hardware to achieve broad frequency coverage without proportionally increasing complexity.
3Reliability
If aggressive noise cancellation is applied to reduce environmental noise, then noise reduction efficacy is improved, but unwanted noise sounds are introduced
Solution Approach 1:
The feedback-based ANR configuration continuously monitors the output and adjusts the cancellation signal accordingly. This feedback mechanism detects and corrects unwanted artifacts in real-time, allowing aggressive noise cancellation to be applied while minimizing the introduction of unwanted sounds through continuous optimization.
Solution Approach 2:
The system applies partial ANR action by selectively targeting specific frequency ranges and environmental noise types rather than attempting to cancel all sounds equally. This selective approach reduces the generation of unwanted artifacts while still achieving effective noise reduction for the most problematic frequencies.
4Duration of action of moving object
If battery power is reduced to extend battery life, then duration of action is improved, but noise reduction efficacy decreases
Solution Approach 1:
The system employs periodic switching between high-power and low-power ANR modes based on environmental conditions and battery state. During periods of low battery charge, the system transitions to more efficient operating modes that maintain adequate noise reduction while consuming less power, thus extending battery life without permanently sacrificing efficacy.
Solution Approach 2:
The ANR circuit dynamically adjusts its operational characteristics including the degree of ANR application, the frequency ranges processed, and the signal processing intensity based on available power. This dynamic adaptation allows the system to optimize the trade-off between battery life and noise reduction efficacy in real-time.
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
Incorporating first/second ADCs A1/A2 of an ANR circuit, first/second pluralities P1/P2 of digital filters of a quantity specified by first/second sets S1/S2 of ANR settings, and DACs into first/second pathways Pa1/Pa2; selecting a type of digital filter specified by S1 for each digital filter of P1/P2; adopting a signal processing topology specified by S1 by configuring interconnections among at least A1/A2, P1/P2 and the DAC so that digital data representing sounds flows through Pa1 from A1 to the DAC through at least P1; digital data representing sounds flows through Pa2 from A2 to the DAC through at least P2; Pa1/Pa2 are combined at first/second locations along Pa1/Pa2 such that the digital data are combined before flowing to the DAC; configuring each digital filter with filter coefficients specified by S1; setting a data transfer rate at which digital data flows through at least a portion of Pa1/Pa2 as specified by S1; operating A1/A2, P1/P2 and the DAC to provide ANR in the earpiece; changing an ANR setting specified by S1 to one specified by S2 in synchronization with a transfer of digital data along at least a portion of Pa1/Pa2; monitoring a characteristic of a sound represented by digital data; wherein changing an ANR setting occurs in response to a change in the characteristic, changing an interconnection of the signal processing topology defined by S1, a selection of a digital filter specified by S1, a filter coefficient specified by the S1, and a data transfer rate specified by S1.