Acoustic Feedback Suppression via Frequency-Dependent Gain Attenuation
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Solution Overview
Problem
Existing audio signal processing systems face challenges in reducing howling caused by acoustic feedback without compromising the optimization of noise reduction techniques, particularly in communication systems where background noise and unwanted audio signals interfere with speech transmission.
Innovation Solution
A method that identifies frequencies causing higher system gain in an acoustic system, applies a noise attenuation factor based on the system gain for each frequency, and adjusts noise reduction accordingly to mitigate howling while maintaining perceptual quality, by estimating or measuring system gain for each frequency and applying noise attenuation factors across frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If noise reduction techniques are applied to improve speech quality, then perceptual quality is improved, but howling caused by acoustic feedback increases
Solution Approach 1:
The patent applies different noise attenuation factors to different frequency components based on their individual system gain characteristics. Frequencies with high system gain (prone to howling) receive stronger attenuation, while frequencies with average system gain receive standard attenuation. This localized differentiation resolves the contradiction by targeting noise reduction specifically where it causes problems rather than applying uniform suppression.
Solution Approach 2:
The patent dynamically adjusts the noise attenuation factor for each frequency component based on the measured system gain at that frequency. By changing the attenuation parameter adaptively rather than using a fixed value, the system maintains speech quality where system gain is acceptable while suppressing howling where system gain is excessively high.
2Device complexity
If uniform noise attenuation is applied across all frequencies, then noise reduction is simplified, but speech quality degradation occurs due to excessive attenuation of important frequency components
Solution Approach 1:
Instead of applying uniform noise attenuation across all frequencies, the patent calculates and applies frequency-specific attenuation factors based on measured system gain characteristics. This localized approach prevents excessive attenuation of important speech frequencies while still reducing noise, thereby maintaining speech quality without significantly increasing system complexity.
3Power
If system gain is increased to improve signal transmission, then signal strength is improved, but howling becomes more likely
Solution Approach 1:
The patent measures system gain separately for different frequency components and identifies specific frequencies where system gain is excessively high. By applying targeted noise attenuation only to these problematic frequency components rather than uniformly reducing gain across the spectrum, the system maintains strong signal transmission where appropriate while suppressing howling where system gain is too high.
Data Source
AI summary
According to an embodiment, a method of reducing noise in a signal received at a processing stage of an acoustic system includes, at the processing stage identifying at least one frequency which causes a system gain of the acoustic system to be above an average system gain of the acoustic system; providing a noise attenuation factor for reducing noise in the signal for the at least one frequency, the noise attenuation factor for the at least one frequency based on the system gain for that frequency; and applying the noise attenuation factor to a component of the signal at that frequency.