Sensor Signal Acquisition with Offset and Gain Correction
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Solution Overview
Problem
Existing methods for correcting offset and gain errors in analog signal digitization require signals to be temporally constant, making them slow and inefficient.
Innovation Solution
A method that allows for the determination of measurement values corrected for offset and gain without waiting for the settling of ADC input levels, using a system where output variables achieve at least 86% of the change with modified input variables, and employing a multiplexer to connect reference and measurement voltages to ADC inputs, with calculations based on obtained digital values to compensate for errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the method waits for the settling of ADC input levels before digitization, then measurement precision is improved, but productivity deteriorates
Solution Approach 1:
The patent performs preliminary calibration measurements to determine offset and gain values before actual signal measurement. By pre-characterizing the ADC's offset and gain errors through reference voltage measurements, the system can compensate for these errors during normal operation without waiting for signal settling, thus maintaining precision while improving speed
Solution Approach 2:
The patent implements a feedback mechanism where the measured offset and gain values are used to correct subsequent measurements. The system continuously monitors and compensates for ADC errors by applying correction factors derived from preliminary reference measurements, enabling fast acquisition while maintaining accuracy
2Productivity
If the method does not wait for settling of ADC input levels, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The patent replaces the mechanical/waiting-based settling process with a mathematical correction approach. Instead of physically waiting for signals to stabilize, the system uses calculated correction factors (offset and gain values) to compensate for non-settled conditions, substituting time-consuming physical processes with computational corrections
Solution Approach 2:
The patent changes the operational parameters by performing measurements at defined time points relative to multiplexer switching, rather than waiting for natural settling. By measuring at specific intervals and applying temporal correction factors, the system transforms the approach from passive waiting to active timed measurement with mathematical compensation
3Measurement precision
If multiple individual measurements are performed for offset and gain correction, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the measurement system universal by using the same ADC and multiplexer infrastructure for both reference voltage measurements (for offset/gain determination) and actual signal measurements. The single measurement unit performs multiple functions: calibration, offset measurement, gain measurement, and signal acquisition, eliminating the need for separate dedicated hardware for each function
Data Source
AI summary
A method for precise acquisition of a signal of a sensor, by an evaluation and control unit which has a multiplexer at whose inputs there is at least one reference voltage whose voltage value is known, a ground potential of the reference voltage, a measurement signal of the exhaust gas sensor, and a ground potential of the measurement signal. A computer is connected downstream from the multiplexer via a transmission path and via an ADC that converts a voltage between its two inputs into a digital value. The method provides that a plurality of individual measurements are carried out in which switching states of the multiplexer are modified, and digital values are subsequently acquired at the output of the ADC. The computer calculates a measurement value, corrected with regard to offset and gain, from these digital values.