Capacitive Sensor Sampling Delay Tuning for Noise Rejection
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Solution Overview
Problem
Capacitive touch sensors face significant noise interference from environmental sources, leading to decreased signal quality and increased response times, as existing solutions lack active noise tuning capabilities and rely on static optimization techniques.
Innovation Solution
A method that dynamically modifies sampling waveform delays and employs noise detection and filtering to optimize signal-to-noise ratio in real-time, adjusting oversampling and timing parameters based on noise levels to minimize noise impact while maintaining response time requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is sampled multiple times to verify the result was not an accident due to random variation, then noise rejection is improved, but response time increases
Solution Approach 1:
The patent applies dynamics by making the sampling rate adjustable rather than fixed. The system dynamically modifies sampling waveform delays and adjusts oversampling counts based on detected noise levels, allowing the sampling process to adapt between taking multiple samples for noise rejection or fewer samples for faster response depending on environmental conditions
Solution Approach 2:
The patent changes parameters by modifying sampling waveform delays and oversampling counts based on noise detection. The system adjusts these parameters dynamically - increasing oversampling when noise is detected and decreasing it when the environment is quiet, thereby optimizing the balance between noise rejection and response time
2Reliability
If a fixed sampling rate is used, then the system performs well at some noise frequencies, but other frequencies cause the signal to degrade to the point of inoperability
Solution Approach 1:
The patent makes the sampling system dynamic by allowing real-time adjustment of sampling waveform delays. This enables the system to adapt to different noise frequencies by changing the timing characteristics of sampling, transforming a static system into one that can respond to varying environmental noise conditions
Solution Approach 2:
The patent changes sampling parameters including waveform delays and oversampling counts based on detected noise characteristics. By modifying these parameters in response to different noise frequencies, the system maintains signal quality across a broader range of frequency conditions than a fixed sampling rate could achieve
3Reliability
If oversampling is increased to reduce noise, then noise rejection is improved, but response time increases
Solution Approach 1:
The patent applies dynamics by making oversampling counts adjustable rather than fixed. The system dynamically modifies oversampling based on noise detection - using higher oversampling rates when noise is present and lower rates when the environment is quiet, allowing adaptive optimization of the noise rejection versus response time tradeoff
Solution Approach 2:
The patent changes the oversampling parameter based on noise levels. The system increases oversampling counts when noise is detected to improve rejection, and decreases them when noise levels are low to maintain fast response times, thereby optimizing performance across varying conditions
Data Source
AI summary
A system for reducing noise in a sensor measurement system includes a noise detector for detecting noise in capacitive to digital conversion measurements; a noise correction module operably coupled to the noise detector and configured to dynamically modify one or more delays associated with a sampling waveform; and a noise filter for filtering the sampling waveform.