Dynamic-Range Microphone Voltage Control for High-SPL Recording
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Solution Overview
Problem
Internal microphones in mobile devices often saturate and distort when capturing high sound pressure levels, leading to poor audio quality in live event recordings due to their inability to handle high amplitude audio signals effectively.
Innovation Solution
A method and apparatus that utilize a single microphone element connected to an ASIC with a charge pump to vary the supply voltage based on distortion levels, reducing sensitivity and preventing overdriving, allowing for clear audio capture in high sound pressure environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the microphone sensitivity is increased to capture low sound pressure levels, then the audio quality for normal sounds is improved, but the microphone saturates and distorts when capturing high sound pressure levels
Solution Approach 1:
The patent implements dynamic adjustment of the microphone supply voltage based on the detected sound pressure level. The system transitions from a static voltage supply to a dynamic one that adapts in real-time, allowing the microphone to operate optimally across varying acoustic conditions without saturation or distortion
Solution Approach 2:
The patent changes the electrical parameter (supply voltage) of the microphone based on the acoustic conditions. By detecting the sound pressure level and adjusting the voltage accordingly, the system optimizes the microphone's sensitivity to match the ambient acoustic environment, preventing both poor capture of quiet sounds and saturation from loud sounds
2Device complexity
If a single microphone element is used to simplify the device, then the device complexity is reduced, but the dynamic range and ability to handle high SPL signals is limited
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the output signal for signs of saturation or distortion and automatically adjusts the supply voltage in response. This closed-loop control allows a single microphone element to adapt its performance characteristics to maintain optimal operation across a wide dynamic range
Solution Approach 2:
The system performs self-adjustment by automatically detecting when the microphone is approaching saturation and correcting the supply voltage without external intervention. This self-service capability allows the single microphone element to autonomously optimize its performance for the current acoustic conditions
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
Enables high sound pressure audio recording without distortion by dynamically adjusting the microphone sensitivity through voltage variation, improving audio quality in high SPL environments for both voice and audio-visual recordings.
Implementation Method 1
circuitry comprising a charge pump configured to vary a supply voltage connected to the input audio transducer
Data Source
AI summary
Disclosed herein are apparatus, method, and computer program product whereby a device receives an acoustic signal, where the acoustic signal has a variable sound pressure level. A device outputs an electrical signal from an input audio transducer, where the input audio transducer is connected to a supply voltage. The device determines a distortion level of the electrical signal; and increases or decreases the supply voltage based on the distortion level.