ADC Non-Linearity Correction With Real-Time Coefficient Estimation
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Solution Overview
Problem
Analog-to-digital converters (ADCs) face challenges in meeting stringent harmonic distortion and intermodulation distortion specifications due to non-linearity issues, which are not adequately addressed by factory calibration methods, as they do not account for operational variations such as temperature, voltage, and aging, leading to increased device costs and memory requirements for storing correction coefficients.
Innovation Solution
A non-linearity correction circuit that determines correction coefficients in real-time using a data path and reference path, employing a non-linearity coefficient estimation circuit that captures data, generates non-linearity terms, and converts them to the frequency domain for identifying bins with high non-linearity and low signal power, allowing for dynamic correction without the need for factory calibration or extensive memory storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If factory calibration methods are used to correct ADC non-linearity, then initial non-linearity correction is achieved, but operational variations such as temperature, voltage, and aging are not accounted for, leading to degraded performance over time
Solution Approach 1:
The patent implements dynamic non-linearity correction by continuously tracking and updating correction coefficients based on real-time operational conditions. The system transitions from static factory calibration to dynamic adaptation, where correction parameters are adjusted according to temperature, voltage, and aging variations, ensuring maintained precision across changing operational environments.
Solution Approach 2:
The ADC system performs self-correction by automatically measuring its own non-linearity errors and generating correction coefficients without external intervention. The built-in correction circuitry continuously monitors performance degradation and applies real-time compensation, enabling the system to maintain accuracy autonomously throughout its operational lifecycle.
2Measurement precision
If extensive memory storage is allocated for storing correction coefficients, then comprehensive non-linearity correction is achieved, but device costs increase
Solution Approach 1:
The patent changes the parameter representation by using compact coefficient models that require minimal storage. Instead of storing extensive lookup tables for all possible non-linearity conditions, the system uses parameterized correction functions with few coefficients that can adapt to various operational scenarios, dramatically reducing memory requirements while maintaining correction effectiveness.
Solution Approach 2:
The patent extracts only the essential correction parameters needed for effective non-linearity compensation, discarding redundant data. By identifying and retaining only the critical coefficients that capture the dominant non-linearity behavior, the system achieves comprehensive correction coverage with minimal storage, eliminating unnecessary memory overhead.
3Manufacturing precision
If in-factory calibration is performed, then initial correction coefficients are established, but real-time adaptation to operational conditions is not achieved
Solution Approach 1:
The patent ensures continuous non-linearity correction by maintaining ongoing coefficient updates throughout the ADC's operational lifetime. Rather than performing correction only during factory calibration, the system continuously adapts to changing conditions, ensuring uninterrupted and evolving correction accuracy that persists across the entire product lifecycle.
Solution Approach 2:
The system implements feedback mechanisms where actual ADC output is compared against expected linear behavior, and the error information is fed back to update correction coefficients in real-time. This closed-loop approach allows the system to learn from operational experience and continuously refine its correction accuracy, bridging the gap between initial calibration and ongoing performance.
Data Source
AI summary
A non-linearity correction circuit includes a non-linearity coefficient estimation circuit. The non-linearity coefficient estimation circuit includes a data capture circuit, a non-linearity term generation circuit, a time-to-frequency conversion circuit, a bin identification circuit, a residual non-linearity conversion circuit, and a non-linearity coefficient generation circuit. The non-linearity term generation circuit is coupled to the data capture circuit. The time-to-frequency conversion circuit is coupled to the data capture circuit and the non-linearity term generation circuit. The bin identification circuit is coupled to the time-to-frequency conversion circuit. The residual non-linearity conversion circuit is coupled to the bin identification circuit. The non-linearity coefficient generation circuit is coupled to the bin identification circuit and the residual non-linearity conversion circuit.