Multipath Digital Microphone ADC Switching for High Dynamic Range
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Solution Overview
Problem
Conventional digital microphones face challenges in achieving high dynamic range (DR) while maintaining low power consumption, often requiring excessive power or introducing noise artifacts due to limitations in analog-to-digital converter (ADC) design and automatic gain control (AGC) systems.
Innovation Solution
The implementation of an adaptive multipath digital microphone system that employs adaptive ADCs with variable sampling capacitance and capacitive-based feedback networks, allowing for dynamic gain adjustment and reduced noise, along with a two-path architecture that selects between low and high signal paths based on sound pressure levels to achieve high DR without excessive power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional high DR ADC or AGC techniques are employed to improve dynamic range, then dynamic range is improved, but power consumption increases excessively
Solution Approach 1:
The patent divides the audio signal processing into two separate paths: a first path with higher gain for low-level signals and a second path with lower gain for high-level signals. Each path has its own ADC optimized for its specific signal range. This segmentation allows each ADC to operate efficiently in its designated range without requiring excessive power consumption, while collectively achieving high dynamic range coverage.
Solution Approach 2:
The patent implements dynamic path selection based on the input signal level. A path selection mechanism dynamically switches between the first and second signal paths depending on whether the input signal is below or above a threshold level. This dynamic adaptation allows the system to optimize power consumption by activating only the necessary path for the current signal conditions while maintaining high dynamic range performance.
2Measurement precision
If conventional AGC amplifier is used to lower ADC DR requirements, then ADC DR requirements are reduced, but noise artifacts are introduced
Solution Approach 1:
Instead of using a single AGC amplifier that introduces noise artifacts across the entire signal range, the patent segments the signal processing into two paths with fixed gain stages. Each path is optimized for its specific signal level range, eliminating the need for AGC-induced gain adjustments and the associated noise artifacts while still meeting ADC dynamic range requirements.
3Measurement precision
If multipath approach with combining algorithm is used to achieve high DR, then dynamic range is improved, but instantaneous saturation effects occur
Solution Approach 1:
Instead of combining signals from multiple paths after ADC conversion (which can cause saturation), the patent inverts the approach by selecting only one path's output based on the input signal level. The path selection mechanism ensures that only the appropriate path is active at any given time, preventing saturation effects while maintaining high dynamic range performance through proper signal routing.
Data Source
AI summary
Exemplary multipath digital microphone described herein can comprise exemplary embodiments of adaptive ADC range multipath digital microphones, which allow low power to be achieved for amplifiers or gain stages, as well as for exemplary adaptive ADCs in exemplary multipath digital microphone arrangements described herein, while still providing a high DR digital microphone systems. Further non-limiting embodiments can comprise an exemplary glitch removal component configured to minimize audible artifacts associated with the change in the gain of the exemplary adaptive ADCs.