AD Conversion Calibration for Continuous Bit-Extended Measurement
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Solution Overview
Problem
Conventional AD conversion techniques face challenges in ensuring data continuity between amplified and direct conversion results due to gain errors and offsets in amplifier circuits, particularly in low-level voltage measurements, requiring complex calibration processes.
Innovation Solution
A data processing device employing a DA converter circuit, an amplifier circuit, and an AD converter circuit under control of a control circuit, where the analog signal is directly converted and amplified, allowing for calculation and cancellation of gain errors, and subsequent bit extension to ensure data continuity across different bit precision levels without high-precision amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an amplifier circuit is used to amplify low-level voltage signals before AD conversion, then the bit precision of conversion results is improved, but data continuity between amplified and direct conversion results deteriorates due to gain errors and offsets
Solution Approach 1:
The system performs preliminary calibration by converting the same analog signal through both direct AD conversion and amplifier-based AD conversion, then calculates gain error and offset values before actual measurement. This preliminary characterization of the amplifier circuit allows subsequent correction of gain errors and offsets, ensuring data continuity while maintaining high bit precision for low-level voltage signals
Solution Approach 2:
The system uses feedback by comparing the direct conversion result with the amplified conversion result to calculate correction values (gain error and offset). These correction values are then applied to the amplified conversion results to compensate for amplifier imperfections, creating a closed-loop error correction mechanism that maintains data continuity across different conversion paths
2Measurement precision
If conventional amplifier circuits are used for signal amplification, then signal level is improved, but device complexity increases due to required error calibration processes
Solution Approach 1:
The system performs self-calibration by automatically calculating its own gain error and offset values through digital processing of conversion results. The microunit executes calibration routines that characterize the amplifier circuit's errors and applies corrections without requiring external calibration equipment or manual adjustment, simplifying the overall system while maintaining measurement precision
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 ensures easy data continuity in AD conversion with varied bit precision without the need for error-calibration of amplifier circuits, maintaining precision and reducing complexity in calibration processes.
Implementation Method 1
a DA converter circuit (4)
Implementation Method 2
an amplifier circuit (5)
Implementation Method 3
an AD converter circuit (3)
Data Source
AI summary
In AD conversion of a voltage under measurement, data continuity is ensured between the result of conversion after amplification by using an amplifier circuit and the result of direct conversion without using the amplifier circuit. In AD conversion operation using a DA converter circuit, an amplifier circuit, and an AD converter circuit under the direction of a control circuit, an analog signal output from the DA converter circuit is directly converted by the AD converter circuit, and also the analog signal is converted therein after amplified by the amplifier circuit with an expected gain of 2n (“n” represents a positive integer). Based on resultant data thus obtained, a gain of the amplifier circuit and an offset thereof are calculated. An analog signal under measurement to be enhanced in bit precision is subjected to amplification by the amplifier circuit and conversion by the AD converter circuit, the offset calculated as mentioned above is subtracted from the result of the conversion, and the result of the subtraction thus performed is multiplied by a ratio of the expected gain to the gain calculated as mentioned above so as to cancel a gain error. Then, based on data with the gain error canceled, acquisition of bit-extended conversion result data is performed to ensure continuity between data having different degrees of bit precision.