Dual Directional Microphone Layout for High-Noise Speech Capture
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Solution Overview
Problem
Communication in noisy environments is challenging due to unwanted noise interference, especially when using microphones in electronic devices like communication radios and cellular telephones.
Innovation Solution
A dual microphone configuration (DMC) with two directional microphones positioned close to the speaker's mouth, one capturing more speech and the other capturing noise, is used in conjunction with an adaptive noise removal system to suppress noise, utilizing the Pathfinder system for noise cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single microphone is used in noisy environments, then the device complexity is low, but the noise suppression capability is insufficient
Solution Approach 1:
The system divides the noise suppression task into two separate microphone functions: one microphone captures speech signals while another captures noise signals. This segmentation allows each microphone to specialize in capturing specific acoustic components, enabling effective noise suppression through signal processing without requiring a complex array of multiple microphones at various positions.
Solution Approach 2:
The patent introduces an adaptive filter as an intermediary component that processes signals from both microphones. This intermediary element combines the speech signal from the first microphone with the noise signal from the second microphone to produce a cleaned output signal, effectively mediating between the raw inputs and the final suppressed output.
2Measurement precision
If microphones are positioned close to the speaker's mouth, then speech capture is improved, but noise from the environment is also captured more
Solution Approach 1:
The system applies local quality by giving each microphone a specialized function: the first microphone is optimized for capturing speech signals from the speaker's mouth, while the second microphone is positioned and configured to capture environmental noise. This differentiation in local function allows the system to simultaneously improve speech capture while managing noise capture through dedicated sensors.
Solution Approach 2:
The patent converts the harmful effect of noise capture into a beneficial element by using the second microphone specifically to capture noise that would otherwise be unwanted. This captured noise signal is then used by the adaptive filter to subtract noise from the speech signal, transforming the previously harmful noise capture into a useful function for noise suppression.
3Object-affected harmful factors
If dual microphone configuration is implemented, then noise reduction is achieved, but the device complexity increases
Solution Approach 1:
The system segments the noise suppression function across two microphones with distinct roles, avoiding the need for complex microphone arrays with multiple elements positioned at various locations. This segmentation achieves effective noise reduction while maintaining relatively simple device architecture.
Solution Approach 2:
The patent replaces complex mechanical microphone array configurations with a simpler dual-microphone setup combined with digital signal processing. Instead of using multiple microphones positioned at different spatial locations to achieve noise suppression through physical geometry, the system uses adaptive filtering to achieve the same effect with fewer physical components.
Data Source
AI summary
A microphone array is described for use in ultra-high acoustical noise environments. The microphone array includes two directional close-talk microphones. The two microphones are separated by a short distance so that one microphone picks up more speech than the other. The microphone array can be used along with an adaptive noise removal program to remove a significant portion of noise from a speech signal of interest.