Multipath MEMS Microphone Gain Switching Without Audible Artifacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional digital microphones face challenges in achieving high dynamic range with low power consumption and flexible performance adjustments, often resulting in audible artifacts and limited signal processing capabilities, especially in varying sound pressure level environments.
Innovation Solution
A multipath digital microphone system with a gain adjustment component and power management module that dynamically adjusts gains and power states across multiple signal paths, allowing seamless transitions between operational modes without interruptions, using adjustable ADCs and a multipath digital audio combiner to compensate for gain imbalances and manage power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional digital microphone techniques (high DR ADC or AGC) are employed to improve dynamic range, then dynamic range is improved, but power consumption increases excessively
Solution Approach 1:
The signal processing is divided into multiple parallel paths (first and second signal paths) with different gains. Each path processes the same input signal independently, allowing the system to select or combine paths based on signal level requirements without requiring high-power AGC or high-DR ADC operations in all conditions.
Solution Approach 2:
The system changes the gain parameter of different signal paths based on the detected signal level. When the input signal level is low, the first signal path with higher gain is used; when the input signal level is high, the second signal path with lower gain is used. This dynamic parameter adjustment allows high dynamic range performance without requiring excessively high power consumption.
2Measurement precision
If automatic gain control amplifier is used to lower ADC DR requirements, then ADC DR requirements are reduced, but troublesome artifacts are introduced
Solution Approach 1:
Instead of using a single AGC amplifier that introduces artifacts, the system segments the gain control function across multiple parallel signal paths with fixed different gains. This eliminates the need for dynamic gain adjustment in a single path, thereby avoiding the artifacts that AGC amplifiers typically introduce while still achieving adaptive dynamic range performance.
Solution Approach 2:
The system creates multiple copies of the signal path with different fixed gain settings rather than using a single path with dynamic gain control. This copying approach with fixed gains avoids the artifacts associated with dynamic AGC while maintaining the ability to handle both low and high signal levels effectively.
3Measurement precision
If multipath approaches with combining algorithm are used to improve dynamic range, then dynamic range is improved, but instantaneous saturation effects occur
Solution Approach 1:
The system performs preliminary detection of the signal level before combining or selecting signal paths. By detecting the signal level in advance and selecting the appropriate signal path based on this preliminary information, the system avoids instantaneous saturation effects that would occur if paths were combined without prior level assessment.
Solution Approach 2:
The system dynamically selects between different signal paths based on real-time signal level detection rather than using a static combining algorithm. This dynamic path selection adapts to changing signal conditions and prevents instantaneous saturation by ensuring the appropriate gain path is active for the current signal level.
4Use of energy by moving object
If digital microphone provides only two conventional modes (HQM and LPM), then power consumption is reduced, but performance flexibility is limited
Solution Approach 1:
The system implements dynamic signal path selection based on real-time signal level detection rather than being limited to two fixed operational modes. This allows the microphone to adapt flexibly to any signal level condition by automatically selecting the appropriate signal path, providing continuous performance optimization rather than discrete mode switching.
Solution Approach 2:
The system changes operational parameters (signal path selection) based on detected signal levels rather than being constrained to predefined modes. This enables continuous adaptation to different acoustic environments and signal conditions, providing versatile performance adjustment while maintaining power efficiency.
Data Source
AI summary
Disclosed embodiments provide flexible performance, high dynamic range, microelectromechanical (MEMS) multipath digital microphones, which allow seamless, low latency transitions between audio signal paths without audible artifacts over interruptions in the audio output signal. Disclosed embodiments facilitate performance and power saving mode transitions maintaining high dynamic range capability.