Adaptive Road Noise Cancellation for Entertainment Audio Interference
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Solution Overview
Problem
Existing noise-cancellation systems in vehicles are compromised by loud entertainment audio, particularly deep bass, which can falsely trigger the system, corrupt the audio, and render road noise cancellation unnecessary.
Innovation Solution
Implementing a system that monitors entertainment audio levels and adjusts noise-cancellation thresholds to enable or disable adaptation and attenuation of the noise-cancellation signal based on audio volume, using RMS calculations and hysteresis to manage interference between road and entertainment audio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the noise-cancellation system operates continuously to cancel road noise, then road noise cancellation effectiveness is improved, but entertainment audio quality deteriorates due to false triggering by bass frequencies
Solution Approach 1:
The system dynamically adjusts the adaptation state of the filter based on detected audio characteristics. When bass frequencies are detected, the system transitions to a non-adaptive state to prevent false noise cancellation activation, while maintaining noise cancellation capability when appropriate. This dynamic state switching resolves the contradiction by making the system responsive to operational conditions.
Solution Approach 2:
The system changes the adaptation parameter of the filter based on detected audio conditions. By monitoring bass frequency content and adjusting the adaptation parameter accordingly (enabling or disabling adaptation), the system prevents false triggering while maintaining effective noise cancellation when road noise is present, thus resolving the contradiction between reliability and harmful effects.
2Measurement precision
If the system adapts continuously to road noise conditions, then noise cancellation accuracy is improved, but system stability deteriorates when entertainment audio is playing
Solution Approach 1:
The system uses feedback from audio analysis to control the adaptation process. By continuously monitoring the audio signal for bass frequencies and using this feedback to enable or disable adaptation, the system maintains accuracy when needed while ensuring stability during entertainment playback. The feedback mechanism prevents the system from becoming unstable due to false noise detection.
3Reliability
If noise cancellation is always active, then road noise reduction is improved, but entertainment audio performance deteriorates due to system interference
Solution Approach 1:
The noise cancellation system dynamically adjusts its operational state based on detected audio conditions. When entertainment audio with bass frequencies is detected, the system reduces or disables noise cancellation to eliminate interference. When road noise is detected without entertainment audio, the system activates full noise cancellation, thus resolving the contradiction between noise reduction and system interference.
Data Source
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AI summary
A vehicle-implemented, adaptive noise-cancellation system (100) responsive to entertainment audio is provided. The noise-cancellation system uses reference signal from a reference sensor (106), such as an accelerometer, to generate a noise-cancellation signal to destructively interfere with road noise in the vehicle cabin. A first set of entertainment audio thresholds triggers the system to enable or disable adaptation of an adaptive filter of the noise-cancellation system. A second set of entertainment audio thresholds triggers the system to enable, attenuate, or disable the noise-cancellation signal. As the entertainment audio increases, the system first disables the adaptation of the adaptive filter, then attenuates the noise-cancellation signal, then completely disables the noise-cancellation signal. Conversely, as the entertainment audio decreases, the system first enables the noise-cancellation signal, then reduces the attenuation (thereby increasing the amplitude) of the noise-cancellation signal, and then enables the adaptation of the adaptive filter.