Dual Analog Sensor Interface Bias Switching Against Ionic Contamination
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Solution Overview
Problem
Current calibration processes for aerospace sensor systems do not account for ionic contamination in signal processing systems, leading to a decline in performance and accuracy over time due to temperature variations and ion migration in sensor interfaces.
Innovation Solution
A sensor processing circuit with two independent signal processing interfaces, each connected to a dedicated analog-to-digital converter and switchably connected to a biasing voltage source, alternates the biasing state to prevent ionic contamination by ensuring one interface remains biased while the other recovers from contamination, leveraging the faster ion migration back to the unbiased state at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single signal processing interface is used, then the device complexity is low, but ionic contamination accumulates over time causing accuracy degradation
Solution Approach 1:
The single signal processing interface is divided into two separate interfaces (first and second signal processing interfaces), each with its own analog-to-digital converter. This segmentation allows the system to switch between interfaces, preventing ionic contamination from degrading accuracy in both interfaces simultaneously, thus resolving the contradiction between maintaining high measurement precision and avoiding increased device complexity.
2Reliability
If calibration accounts for ionic contamination, then long-term accuracy is improved, but the calibration process becomes more complex
Solution Approach 1:
The system performs preliminary actions by periodically switching between the two signal processing interfaces before ionic contamination can significantly degrade accuracy. By alternately biasing and unbiasing the interfaces, the system prevents contamination accumulation in advance, maintaining long-term reliability without requiring complex calibration processes that account for ionic contamination.
3Productivity
If the sensor interface remains biased continuously, then signal processing is continuous, but ionic contamination degrades accuracy over time
Solution Approach 1:
The system implements periodic action by alternating the biasing state between the first and second signal processing interfaces. Each interface is biased for a period to perform signal processing, then switched to an unbiased state to allow ionic contamination to correct. This periodic switching maintains continuous productivity through redundancy while preserving measurement precision by preventing contamination accumulation.
4Adaptability or versatility
If temperature variations are accommodated, then operational range is improved, but ion migration increases causing contamination
Solution Approach 1:
The system segments the signal processing function across two independent interfaces, allowing it to operate across a wide temperature range while mitigating ionic contamination. When temperature variations cause increased ion migration in one interface, the system can switch to the other interface that has not been subjected to the same thermal stress, thus maintaining adaptability while reducing the harmful effects of ionic contamination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach maintains sensor accuracy within tolerances by rapidly correcting ionic contamination, ensuring continuous high-accuracy readings even at extreme temperatures, and can be enhanced with additional redundant sensors for increased robustness.
Implementation Method 1
ionic contamination occurs slowly over time as a result of ordinary sensor use. The lack of accounting for ionic contamination during calibration causes a decline in performance over time due to a decline in repeatability, and a corresponding loss in accuracy.
Implementation Method 2
A sensor processing circuit with two independent signal processing interfaces, each connected to a dedicated analog-to-digital converter and switchably connected to a biasing voltage source, alternates the biasing state to prevent ionic contamination
Implementation Method 3
EP 0367927 discloses a sensor arrangement in which differential output signals from a pressure sensor are switched between two amplifiers and fed to a microcomputer where they are stored as two pairs of signals in digital form.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An analog interface processing circuit includes a first and second signal processing interface 222, 224, a processing system 240 connected to the first and second signal processing interfaced, a biasing voltage source 250 switchably coupled to said first signal processing interface via a first switch assembly 252 and switchably coupled to said second signal processing interface via a second switch assembly 254, and first control output of said processing system controllably coupled to said first switch assembly and a second control output of said processing system controllably couple to said second switch assembly,