TI-ADC Mismatch Calibration Using NRZ Signals and Genetic Parameters
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Solution Overview
Problem
Time-interleaved analog-to-digital converters (TI-ADCs) experience mismatches due to variations in analog-to-digital converters and signal paths, leading to inaccuracies in high-speed communication and signal analysis applications.
Innovation Solution
An apparatus and method that includes a time-interleaved analog-to-digital converter and a mismatch corrector. The mismatch corrector processes the first output signal from the TI-ADC based on parameters generated using a genetic algorithm, effectively correcting mismatches and improving signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time-interleaved analog-to-digital converters are used to achieve high sampling rates, then productivity is improved, but manufacturing precision deteriorates due to mismatches between parallel converters
Solution Approach 1:
The system divides the high-speed conversion task into multiple parallel ADCs operating at lower individual rates, with each converter handling a portion of the sampling burden. This segmentation enables high overall sampling rates while individual converters operate within their precision capabilities.
Solution Approach 2:
The patent applies correction parameters derived from calibration signals to adjust the output of each parallel ADC. By changing the parameters (gain, offset, timing) of individual converters based on measured mismatches, the system compensates for manufacturing variations and maintains high conversion accuracy.
2Productivity
If multiple parallel analog-to-digital converters are used, then productivity is improved, but device complexity increases due to mismatch correction requirements
Solution Approach 1:
The system performs preliminary calibration by inputting a known test signal and measuring the actual output of each parallel ADC before normal operation. This preliminary action characterizes the mismatches and establishes correction parameters that are stored and applied during subsequent conversions, avoiding the need for complex real-time correction mechanisms.
Solution Approach 2:
The patent implements a feedback mechanism where the correction parameters are continuously refined based on calibration measurements. The system measures the output of parallel converters, compares it against expected values, and adjusts the correction parameters accordingly to minimize mismatches, creating a self-correcting system that manages complexity through adaptive feedback.
3Measurement precision
If calibration signals with periods matching the sampling period product are used, then measurement precision is improved, but adaptability deteriorates due to limited frequency range coverage
Solution Approach 1:
The patent employs a universal calibration signal generation mechanism that can produce test signals with various periods and frequencies. The calibration system is designed to handle multiple frequency ranges by adjusting the test signal characteristics, making the same correction apparatus adaptable to different operating conditions and frequency requirements without needing separate specialized systems.
Solution Approach 2:
The calibration system dynamically adjusts the period and frequency of test signals based on the operating conditions and the specific mismatch characteristics being measured. By making the calibration signal dynamic rather than fixed, the system can optimize measurement precision for different frequency ranges and adapt to various operational scenarios.
Data Source
AI summary
An apparatus and a method of correcting a mismatch of a time-interleaved analog-to-digital converter are provided. The apparatus may include: a time-interleaved analog-to-digital converter configured to receive a non-return-to-zero (NRZ) signal in a correction mode and generate a first output signal, and including a plurality of analog-to-digital converters; and a mismatch corrector configured to generate a second output signal by processing the first output signal of the time-interleaved analog-to-digital converter based on parameters, wherein the parameters may be generated based on the first output signal of the time-interleaved analog-to-digital converter in the correction mode, and a period of the NRZ signal may be different from a product of a sampling period of the time-interleaved analog-to-digital converter and a number of the plurality of analog-to-digital converters included in the time-interleaved analog-to-digital converter.