Sigma-Delta Modulator Switching Using Integrator State Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Digital microphones face challenges in dynamically changing signal processing parameters without causing audible artefacts, particularly when switching between operational modes or adjusting parameters like gain, sampling clock frequency, or sampling capacitance values.
Innovation Solution
A digital microphone system that includes a state detection and control component monitoring the output of integrators to adjust parameters such as gain or sampling capacitance only when the integrator is at a mean value or within specific thresholds, minimizing transients and artefacts during switching events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital microphones dynamically change signal processing parameters (gain, sampling clock frequency, sampling capacitance) to adapt to different operational modes, then adaptability and versatility are improved, but audible transients and artefacts are generated during switching events
Solution Approach 1:
The system performs preliminary action by detecting the integrator state before parameter switching occurs. The state detection component monitors whether the integrator output is at or near zero (mean value) before allowing parameter changes. This preliminary check ensures that switching only happens when the integrator is in a safe state, preventing the generation of audible transients and artefacts while maintaining adaptability across different operational modes.
2Productivity
If parameter switching is performed without monitoring integrator state, then switching speed and productivity are improved, but audible transients and artefacts are generated
Solution Approach 1:
The system implements feedback by continuously monitoring the integrator output state and using this information to control when parameter switching is permitted. The state detection component provides real-time feedback about the integrator condition, and this feedback controls the switching operation. This feedback mechanism ensures that parameter changes only occur when the integrator is at or near zero, eliminating audible transients while maintaining efficient switching operation.
3Reliability
If complex circuit architecture is used to prevent transients during switching, then reliability is improved, but device complexity increases
Solution Approach 1:
The system applies self-service by utilizing the existing integrator's natural state (its output value) to control the switching operation. Rather than introducing complex external control circuits, the system lets the integrator's own state determine when switching is safe to perform. This self-service approach achieves reliable artifact-free switching while adding minimal circuit complexity, as the control logic simply monitors the integrator output and enables switching when appropriate.
Data Source
AI summary
A digital microphone includes at least one integrator; a state detection and parameter control component directly coupled to an output of the integrator; and a signal processing component coupled to an output of the state detection and parameter control component, wherein a parameter of the signal processing component includes a first value in a first operational mode and a second value in a second operational mode different from the first operational mode.