Adaptive Noise Cancellation System for Audio Headsets
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Solution Overview
Problem
Existing noise cancellation systems in personal audio devices struggle to adapt effectively to changing acoustic environments and source audio signals, leading to suboptimal noise reduction.
Innovation Solution
An adaptive noise cancellation system integrated into personal audio devices that generates an anti-noise signal by adapting its response based on the presence and characteristics of the source audio signal, including persistence and spectral density, using a combination of feedforward and secondary path filters to minimize ambient noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adaptive noise cancellation system continuously adapts its response, then noise cancellation performance is improved, but system stability deteriorates when source audio signal is present
Solution Approach 1:
The system dynamically adjusts its adaptation behavior based on the presence of source audio signals. The adaptive filter selectively enables or disables adaptation of the secondary path response depending on whether music or speech is detected, allowing the system to optimize performance in each condition while maintaining stability when source signals are present
2Speed
If the system adapts in the presence of source audio signal, then adaptation speed is improved, but noise cancellation accuracy deteriorates
Solution Approach 1:
The system performs preliminary adaptation when no source audio is present, establishing an initial secondary path model before source signals arrive. This preliminary action allows the system to be ready for rapid adaptation when needed while avoiding the contamination that would occur if adaptation tried to happen simultaneously with source signal playback
3Adaptability or versatility
If multiple adaptive filters are used to handle different acoustic environments, then adaptability is improved, but device complexity increases
Solution Approach 1:
The system uses a single adaptive filter structure that serves multiple functions by selectively adapting to different conditions. The same filter handles both music and speech scenarios, as well as near-field and far-field acoustic environments, by dynamically adjusting its adaptation behavior rather than requiring separate dedicated filters for each scenario
Data Source
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AI summary
An integrated circuit for implementing at least a portion of a personal audio device may include an output and a processing circuit. The output may provide an output signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer. The processing circuit may implement an adaptive noise cancellation system that generates the anti-noise signal to reduce the presence of the ambient audio sounds heard by the listener by adapting, based on a presence of the source audio signal, a response of the adaptive noise cancellation system to minimize the ambient audio sounds at the acoustic output of the transducer, wherein the adaptive noise cancellation system is configured to adapt both in the presence and the absence of the source audio signal.