Adaptive Noise Reduction Filter Switching for Earphone Interference
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Solution Overview
Problem
Feedback noise reduction systems are susceptible to external interference, leading to self-excited oscillations and abnormal sounds such as howling or periodic oscillations, which affect the listening effect.
Innovation Solution
A method and system that detect the morphological changes in the acoustic channel between a microphone and a speaker, switching from a first noise reduction filter to a second filter with a lower frequency response when interference is detected, to effectively resist external interference and maintain system stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feedback noise reduction system uses a standard noise reduction filter, then noise cancellation performance is improved, but the system becomes susceptible to external interference causing self-excited oscillation and abnormal sounds
Solution Approach 1:
The patent changes the frequency response parameters of the noise reduction filter by switching between a first filter (with higher frequency response) and a second filter (with lower frequency response). This parameter change allows the system to adapt to different acoustic conditions and resist external interference while maintaining noise cancellation performance.
Solution Approach 2:
The patent implements dynamic switching between different noise reduction filters based on real-time detection of acoustic channel conditions. The system transitions from a static filter configuration to a dynamic one where the filter characteristics are adjusted according to the detected interference level, thereby improving reliability under varying conditions.
2Object-affected harmful factors
If the feedback noise reduction system switches to a second noise reduction filter with lower frequency response, then resistance to external interference is improved, but noise cancellation effectiveness may be reduced
Solution Approach 1:
The system dynamically switches between the first noise reduction filter (higher frequency response) and the second noise reduction filter (lower frequency response) based on real-time acoustic channel detection. When interference is detected, it switches to the second filter for better interference resistance; when no interference is present, it uses the first filter for optimal noise cancellation, thus maintaining overall effectiveness.
Solution Approach 2:
The system periodically detects the acoustic channel conditions and switches between filters accordingly. This periodic monitoring and switching ensures that the system maintains optimal performance by adapting to changing conditions while preventing sustained use of a single filter configuration that might compromise either noise cancellation or interference resistance.
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 adaptive switching between noise reduction filters improves the system's resistance to external interference, optimizing the listening effect by reducing self-oscillation and maintaining noise reduction performance.
Implementation Method 1
an environmental noise signal is cancelled by using a noise reduction signal, where the noise reduction signal and the environmental noise signal are equal in magnitude and opposite in phase
Data Source
AI summary
A feedback noise reduction method, a feedback noise reduction system, and an earphone are provided. In the method, a channel morphological parameter of an acoustic channel between a microphone and a speaker in a feedback noise reduction system is detected; the feedback noise reduction system is switched from using a first noise reduction filter to using a second noise reduction filter in a case that it is determined that the acoustic channel is in an interfered state based on the channel morphological parameter; and a noise reduction signal is generated by using the second noise reduction filter to cancel a noise signal received by the feedback noise reduction system. A frequency response of the second noise reduction filter in a predetermined frequency band is less than a frequency response of the first noise reduction filter in the predetermined frequency band.