ADC Non-Linearity Correction Using a Reference Signal Path
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Solution Overview
Problem
Existing non-linearity correction methodologies in electronic systems, such as RF-ADC based sampling architectures, face challenges in meeting target performance specifications due to unaccounted non-linearity sources like board circuitry, temperature, voltage, and aging effects, which are not addressed by factory-calibrated correction coefficients.
Innovation Solution
A method that uses a digital signal output from a data signal path and a reference signal output from a reference ADC to estimate non-linearity correction coefficients, allowing for real-time correction of non-linearity components without affecting source non-linearity, and periodic updates to account for changes due to temperature, voltage, and aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If factory-calibrated non-linearity correction coefficients are used, then initial non-linearity compensation is provided, but the correction does not account for dynamic changes due to temperature, voltage, and aging effects
Solution Approach 1:
The patent implements dynamic non-linearity correction by continuously estimating correction coefficients based on real-time operating conditions (temperature, voltage, aging) rather than using static factory-calibrated values. The system adapts to changing environmental and operational parameters, ensuring accurate compensation across diverse operating scenarios.
Solution Approach 2:
The system uses feedback from the ADC output signal and reference signal to continuously estimate and update non-linearity correction coefficients. This closed-loop approach allows the system to self-adjust to changing conditions, improving both reliability and adaptability simultaneously.
2Manufacturing precision
If in-factory calibration and non-volatile storage of correction coefficients are implemented, then performance specifications are met, but device cost increases
Solution Approach 1:
The system performs self-calibration by estimating non-linearity correction coefficients in real-time using the ADC output signal and reference signal. This eliminates the need for expensive in-factory calibration procedures and non-volatile storage, reducing manufacturing costs while maintaining correction performance through continuous adaptive estimation.
Solution Approach 2:
The patent replaces expensive permanent calibration infrastructure with a computationally-efficient real-time estimation algorithm that calculates correction coefficients on-the-fly. This approach uses readily available signals (ADC output and reference) to generate correction factors, eliminating the need for costly calibration equipment and storage infrastructure.
3Reliability
If non-linearity correction is applied to meet target SFDR specifications, then system performance improves, but the complexity of the correction system increases
Solution Approach 1:
The patent introduces a reference ADC as an intermediary component that provides a clean reference signal for estimating non-linearity correction coefficients. This reference signal acts as a mediator between the input signal and the correction process, enabling accurate coefficient estimation without significantly increasing overall system complexity.
Solution Approach 2:
The system replaces complex hardware-based correction mechanisms with a software-based estimation algorithm that operates in the digital domain. By substituting mechanical/calibration-based approaches with computational methods, the system achieves high SFDR performance with reduced physical complexity.
Data Source
AI summary
A method for non-linearity correction includes receiving a first output signal from a data signal path containing a first analog-to-digital converter and receiving a second output signal from a second analog-to-digital converter. The method also includes generating first non-linearity coefficients using the first output signal and generating second non-linearity coefficients using the first and second output signals. The method further includes applying, by a non-linearity corrector in the data signal path, the first and second non-linearity coefficients to compensate for non-linearity components in a digitized signal output from the first analog-to-digital converter to generate a corrected digitized signal.