Multi-Microphone Gain Synchronization for Smooth Audio Switching
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Solution Overview
Problem
Conventional sound pickup systems experience volume differences when switching between microphones due to differing gain settings, leading to sudden volume changes and potential difficulty in hearing speakers with lower gain microphones.
Innovation Solution
A sound pickup device equipped with multiple microphones, each having a first gain controller (AGC) for adjusting gains based on predetermined levels, and a second gain controller that sets and reflects the same gain setting value across all microphones, ensuring consistent volume levels during microphone switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If each microphone has an independent gain controller (AGC) to adjust gain based on predetermined levels, then each microphone can independently control its gain, but volume differences occur when switching between microphones due to different gain settings
Solution Approach 1:
The patent merges the gain control functions by having the second AGC (global gain controller) override and unify the gain settings of all first AGCs (individual microphone gain controllers). This combining approach ensures that all microphones share the same gain setting, eliminating volume differences during switching while preserving the ability of each microphone to independently adjust gain based on its input level.
2Reliability
If the system switches to a microphone with larger gain when noise is detected, then noise can be amplified, but volume becomes large suddenly causing discomfort
Solution Approach 1:
The patent implements a feedback mechanism where the second AGC continuously monitors the output levels of all microphones and adjusts the global gain setting accordingly. When switching between microphones, the second AGC provides feedback to maintain consistent output levels, preventing sudden volume changes while still responding to noise detection by selecting appropriate microphones.
3Loss of energy
If gain is reduced for unselected microphones to save resources, then resource utilization improves, but sound at the beginning of talk becomes difficult to be heard when switching to low-gain microphones
Solution Approach 1:
The patent makes the gain control system universal by having the second AGC set a common gain level for all microphones regardless of which one is currently selected. This allows all microphones to maintain their sound detection capability while the system can switch between them, ensuring that no microphone becomes unusable due to low gain settings.
Data Source
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AI summary
A sound pickup device includes a plurality of microphones, a plurality of first gain controllers controlling a gain of each of the plurality of microphones, an adding portion adding a sound signal to be output from each of the plurality of first gain controllers with a predetermined gain, a second gain controller controlling a gain of the sound signal to be output from the adding portion, and a gain setting portion setting a gain of each of the plurality of first gain controllers based on gain setting in the second gain controller.