Microphone Device Noise Resistance Sensitivity Trade-off
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Solution Overview
Problem
Existing microphone devices struggle to maintain high audio performance and reliability in noisy vehicle environments, as directional microphones offer noise resistance but with poor sensitivity and frequency response, while non-directional microphones are sensitive but vulnerable to noise.
Innovation Solution
A microphone device with a case containing both non-directional and directional MEMS microphones, where a semiconductor chip determines the operating mode based on noise voltage levels, switching between non-directional and directional modes to optimize signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a directional microphone is used to capture sounds only in desired directions, then noise resistance is improved, but sensitivity and frequency response characteristic deteriorate
Solution Approach 1:
The microphone device is segmented into multiple non-directional microphones (first and second microphones) that can be independently controlled. The semiconductor chip selectively activates specific microphones based on noise conditions, allowing the system to achieve directional noise rejection by using only certain microphones while maintaining high sensitivity through the use of non-directional microphone elements.
2Measurement precision
If a non-directional microphone is used to maintain high sensitivity, then sensitivity is improved, but noise resistance deteriorates
Solution Approach 1:
The system dynamically switches between different operational modes by controlling which microphones are active. The semiconductor chip adjusts the operational state of each microphone based on real-time noise conditions, transitioning from using all microphones (high sensitivity mode) to using only specific microphones (noise resistance mode) when noise exceeds the reference threshold.
3Reliability
If multiple microphones are used to achieve both sensitivity and noise resistance, then device complexity increases
Solution Approach 1:
Each microphone unit is designed with universal functionality, incorporating both the non-directional microphone element and the phase delay membrane structure. This allows the same physical component to serve dual purposes: providing high sensitivity through the non-directional element and enabling noise resistance when the phase delay membrane is activated, thereby reducing the need for separate specialized components.
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
The device achieves a high signal-to-noise ratio by selectively operating non-directional microphones for low noise and directional microphones for high noise environments, balancing sensitivity and noise resistance.
Implementation Method 1
a phase delay membrane which is connected to the sound hole in the bottom surface of the case
Implementation Method 2
A capacitive microphone based on microelectromechanical system (MEMS)
Data Source
AI summary
A microphone device includes a case having a sound hole and a phase delay membrane. A plurality of non-directional microphones disposed in the case. A semiconductor chip is connected to the non-directional micro electro mechanical system (MEMS) microphones and operating in response to input signals, in which any one of the non-directional microphones forms a directional microphone by being connected with the sound hole and the phase delay membrane of the case.