Cross-path calibration for multi-range data acquisition
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Solution Overview
Problem
Conventional data acquisition systems face challenges in setting optimal input ranges for non-stationary signals with varying amplitudes, as auto-ranging methods fail to adapt to signals with significant magnitude changes, leading to distorted high signals and buried low signals due to limited dynamic range.
Innovation Solution
The system employs multiple A/D paths with cross-path calibration, where each input signal is directed to at least two paths with different gain settings, allowing for simultaneous sampling and stitching of measurement points to increase dynamic range, and uses cross-path calibration to match gain and offset errors, ensuring smooth signal transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single input range setting is used, then the system is simple to operate, but high signals are clipped and distorted while low signals are buried in noise
Solution Approach 1:
The patent divides the measurement system into multiple A/D paths, each with different gain settings (e.g., unity gain and high gain of 1024). Each path handles a specific signal range, allowing the system to segment the overall dynamic range into manageable portions. This resolves the contradiction by providing simple operation (user selects one path) while maintaining high measurement precision across the entire dynamic range through appropriate path selection.
2Measurement precision
If multiple input range settings are provided, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements intelligent auto-ranging capability that automatically selects the appropriate A/D path based on signal characteristics. The system performs self-service by autonomously determining whether to use unity gain or high gain paths without requiring manual configuration, thus improving measurement precision while minimizing device complexity from the user's perspective.
3Ease of operation
If auto-ranging is implemented, then ease of operation is improved, but it cannot handle non-stationary signals with large amplitude changes
Solution Approach 1:
The patent creates a dynamic system where multiple A/D paths with different gain settings can be selectively activated based on real-time signal characteristics. Unlike traditional auto-ranging that changes range sequentially, this system can rapidly switch between unity gain and high gain paths to adapt to non-stationary signals with large amplitude changes, maintaining both ease of operation and signal adaptability.
4Adaptability or versatility
If multiple A/D paths with different gain settings are used, then dynamic range is increased, but gain and offset errors cause discontinuities during signal transitions
Solution Approach 1:
The patent implements cross-path calibration that uses feedback mechanisms to detect and correct gain and offset errors between different A/D paths. By continuously monitoring and adjusting for path-specific errors, the system maintains signal continuity during transitions between unity gain and high gain paths, resolving the contradiction between expanded dynamic range and measurement precision.
Data Source
AI summary
The present invention utilizes multiple A/D (analog-to-digital) paths and cross-path calibration to provide accurate and reliable measurements for each input channel in a data acquisition system. When the system and method are applied, user and automated methods of selecting among a number of alternative input range settings can be reduced, or even eliminated. That is, there is a significant reduction or complete elimination of input range settings in a measurement system. For each measurement channel of interest, the input signal is directed to at least two paths, e.g., Path A and Path B. The first path measures the full range (e.g., +/â10 volts), while the second path includes a high-gain amplifier. Each path includes an analog-to-digital converter (ADC), so that there is a one-to-one correspondence between the number of paths and the number of ADCs, which sample the input signal simultaneously.