Active Noise Control Device with Dual Processing Chains
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Solution Overview
Problem
Existing noise reduction technologies, such as headphones and earphones, adapt noise control based on noise level but not on the type of noise, failing to effectively attenuate undesirable noise while amplifying useful noise when both have equivalent sound levels.
Innovation Solution
An active noise control device with two passive attenuation earpieces, each equipped with external and internal microphones and a loudspeaker, utilizing a first processing chain with feedforward and feedback filters, and a second processing chain with a sound source identification module to adapt noise control to the type of external noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise control is adapted based on noise level only, then noise attenuation is provided, but useful noise cannot be distinguished from undesirable noise when they have equivalent sound levels
Solution Approach 1:
The patent changes the parameter basis for noise control from noise level only to noise type identification. By analyzing spectral characteristics, temporal patterns, and other parameters of the noise signal, the system distinguishes between useful and undesirable noise sources, enabling selective attenuation based on noise type rather than just overall noise level.
Solution Approach 2:
The patent segments the noise control function into multiple independent processing chains, each dedicated to identifying and handling specific noise types. This segmentation allows the system to treat different noise sources differently, applying appropriate attenuation or amplification to each type while maintaining overall system effectiveness.
2Object-affected harmful factors
If active noise control completely isolates the user acoustically, then noise protection is maximized, but useful sounds such as voices and alarms cannot be perceived
Solution Approach 1:
The patent converts the harmful effect of complete acoustic isolation into a benefit by using the same isolation mechanism to selectively block only undesirable noise while preserving useful sounds. The system identifies useful sounds within the isolated acoustic environment and restores or amplifies them, turning the isolation barrier into a selective filter that protects against harm while maintaining useful information flow.
Solution Approach 2:
The patent performs preliminary identification and classification of noise types before applying attenuation. By预先 identifying useful sounds such as voices and alarms in the noise spectrum, the system prepares restoration or amplification signals in advance, ensuring that useful information is preserved before the noise attenuation process completes.
3Object-affected harmful factors
If noise control is adapted to noise type with multiple processing chains, then noise control effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal noise control architecture where multiple processing chains share common components such as signal acquisition sensors, processing units, and actuation mechanisms. Each processing chain is multi-functional, capable of handling different noise types through configurable parameters and algorithms, reducing overall system complexity while maintaining effectiveness.
Solution Approach 2:
The patent merges the functions of multiple noise processing chains by combining their identification and control algorithms into integrated processing units. The separate processing chains are coordinated to work together, sharing computational resources and control logic, which reduces device complexity while preserving the ability to handle multiple noise types effectively.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively attenuates undesirable noise while amplifying useful noise, improving noise control effectiveness by identifying and processing noise sources, allowing for dynamic adjustment of noise attenuation based on noise type and level.
Implementation Method 1
a loudspeaker (16) which restores a restored noise in the internal acoustic space (11) and in particular in the auditory canal (8) of each ear (9) of the user (2)
Implementation Method 2
each equipped with an external microphone (14) and an internal microphone (15)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Disclosed is an active noise-control device comprising two passive attenuation earphones (3) each provided with an external microphone (14), an internal microphone (15) and a loudspeaker (16). The control device comprises a first processing chain (30) having a feedforward filter, a feedback filter and a reconstruction module. The control device comprises a second processing chain having a sound source identification module, said second processing chain being implemented in parallel with the first processing chain, and being suitable for parameterizing the first processing chain.