Audio Signal Processing Circuit Noise Suppression
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Solution Overview
Problem
The beamforming technique for audio signal processing is affected by noise, particularly from windy or vibrating environments, which disturbs the gain/phase difference between audio signals from microphones, leading to noise interference in the noise frequency band.
Innovation Solution
An audio signal processing circuit that includes a noise detection circuit, a noise cancellation circuit, and a beamforming circuit, where the noise cancellation circuit modifies audio signals by averaging or weighting frequency bands to reduce noise impact, and the beamforming circuit processes differential signals to maintain directivity while discarding or modifying noise frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beamforming technique is used to improve directivity of audio signal recording, then the ability to extract target audio signal from specific direction is improved, but noise from wind or vibration environments disturbs gain/phase difference and deteriorates recording quality
Solution Approach 1:
The patent applies preliminary action by performing noise detection and noise modification processes before the beamforming operation. The noise detection circuit detects noise in advance, and the noise modification circuit modifies the audio signals to reduce noise impact before these processed signals are input to the beamforming circuit, thereby preventing noise from disturbing the gain/phase difference calculation.
Solution Approach 2:
The patent introduces intermediary circuits between the microphones and the beamforming circuit. The noise detection circuit and noise modification circuit act as intermediaries that process the raw audio signals from microphones, removing or reducing noise components before the signals reach the beamforming circuit, thus protecting the beamforming process from noise interference.
2Object-affected harmful factors
If noise cancellation circuit modifies audio signals by processing frequency bands, then noise impact is reduced, but device complexity increases due to additional noise detection and modification circuits
Solution Approach 1:
The patent applies parameter changes by modifying the audio signal parameters (gain/phase difference) in specific frequency bands where noise is detected. The noise modification circuit changes the parameters of the audio signals based on the detection results, selectively adjusting frequency band components to reduce noise impact while maintaining the overall signal integrity.
Solution Approach 2:
The patent applies partial action by not processing all frequency bands uniformly. Instead, the noise modification circuit selectively processes only the frequency bands where noise is detected, leaving other frequency bands unchanged. This partial processing approach reduces the computational burden and circuit complexity compared to processing the entire frequency spectrum.
Data Source
AI summary
An audio signal processing circuit and an electronic device are provided. A noise detection circuit determines if the first input audio signal and a second input audio signal contain noise. The noise cancellation circuit (i), when no noise is detected, outputs a first intermediate audio signal corresponding to the first input audio signal and a second intermediate audio signal corresponding to the second input audio signal without detected noise; (ii) when noise is detected, generates a third intermediate audio signal after performing a specific noise modification process upon the first input audio signal and the second input audio signal, and outputs the first intermediate audio signal including the third input audio signal and the second intermediate audio signal including the third input audio signal. A beamforming circuit performs a beamforming process according to a differential signal of the first intermediate audio signal and the second intermediate audio signal.