Earphone Signal Processing for Noise Reduction
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Solution Overview
Problem
Conventional earphones face challenges in maintaining clear call quality in loud-noise environments due to low signal-to-noise ratio (SNR) and limited high-frequency information, especially with out-of-ear microphones, and external noise interference with in-ear microphones.
Innovation Solution
The implementation of a dual-microphone noise reduction system that combines signals from an out-of-ear microphone and an in-ear microphone to enhance SNR, using beamforming and adaptive filtering techniques to separate voice and noise signals, and fusing intermediate signals to enrich frequency information and reduce external noise pickup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an out-of-ear microphone is used for call collection, then the voice signal can be captured, but the signal-to-noise ratio is low in loud-noise environments
Solution Approach 1:
The patent combines signals from multiple microphones (out-of-ear microphone and in-ear microphone) through signal processing. The out-of-ear microphone captures voice signals while the in-ear microphone captures noise signals, and through beamforming and adaptive filtering, the system merges these signals to enhance the voice signal and suppress external noise, thereby improving the signal-to-noise ratio in loud-noise environments.
2Measurement precision
If an in-ear microphone is used to form a closed cavity, then external noise is suppressed and SNR is improved, but high-frequency information is lost and voice sounds unnatural
Solution Approach 1:
The patent merges the signal from the in-ear microphone (which has high SNR but lacks high-frequency information) with the signal from the out-of-ear microphone (which has external noise but preserves high-frequency information). Through adaptive filtering and beamforming, the system combines these complementary signals to achieve both high SNR and preserved high-frequency content, resulting in natural-sounding voice quality.
3Measurement precision
If dual-microphone noise reduction is implemented, then noise reduction effect is improved, but device complexity increases
Solution Approach 1:
The patent implements dual-microphone noise reduction where the in-ear microphone serves multiple functions: it captures external noise signals for the out-of-ear microphone to reference, and simultaneously provides noise cancellation for the voice signal. This multi-functional approach achieves effective noise reduction while minimizing the increase in device complexity by reusing the in-ear microphone for multiple purposes.
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
This approach significantly improves call quality by increasing SNR, enhancing voice intelligibility, and enriching medium-high frequency information, resulting in a better listening experience in noisy environments.
Implementation Method 1
When a person speaks, vibration of a vocal band is conducted to the cavity formed by the ear canal and an earphone front cavity through tissues such as bones and muscles.
Data Source
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AI summary
Disclosed are an earphone signal processing method and system, and an earphone. A signal picked up by a first microphone of an earphone (S101) at a position close to a mouth outside an ear canal, a signal picked up by a second microphone of the earphone (S 102) at a position away from the mouth outside the ear canal and a signal picked up by a third microphone (S103) in a cavity formed by the earphone and the ear canal are acquired; dual-microphone noise reduction is performed on the signals picked up by the first and second microphones to obtain a first intermediate signal (S 120) or performed on the signals picked up by the second and third microphones to obtain a second intermediate signal (S130); the first and second intermediate signals are fused to obtain a fused voice signal (S140); and the fused voice signal is output (S150).