Time-Interleaved ADC Error Estimation via DC Component Extraction
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Solution Overview
Problem
Time-interleaved analog-to-digital converters (ADCs) face challenges in accurately estimating and correcting timing, gain, and offset errors, which affect their efficiency, and existing methods are either complex or assume specific conditions about input signals.
Innovation Solution
A method that involves using two ADCs to sample an input signal, performing Fourier Transforms on the sampled data, and generating estimated values to correct timing, gain, and offset errors by filtering specific frequency components and analyzing phase and amplitude differences between ADCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test sine wave method is used to estimate timing and gain errors, then error estimation can be performed, but the frequency is constrained and the method assumes zero average input signal with no offset error
Solution Approach 1:
The patent changes the parameter being measured from the traditional test sine wave method to the DC component (average value) of ADC output signals. By focusing on the DC component rather than AC signal characteristics, the method removes constraints on input signal frequency and amplitude, allowing estimation under any input signal conditions including those with non-zero averages.
Solution Approach 2:
The patent extracts only the DC component from the ADC output signals using simple averaging, separating this information from the full signal processing. This extraction approach eliminates the need for complex frequency analysis and removes assumptions about input signal characteristics, making the method universally applicable.
2Ease of manufacture
If a signal statistics principle is used to estimate timing error, then no extra analog signals are required, but complicated calculation in the digital domain cannot be avoided
Solution Approach 1:
The patent extracts only the DC component information from ADC outputs through simple averaging operations, taking out the essential timing error information while discarding all other signal components. This extraction eliminates the need for complicated digital calculations while maintaining estimation accuracy.
Solution Approach 2:
The patent uses the inherent DC component present in normal ADC operation to perform self-diagnosis of timing errors. The system serves itself by utilizing existing operational data rather than requiring external test signals or complex processing, achieving error estimation through simple averaging of regular output signals.
3Measurement precision
If unique sample and hold circuit structure is adopted for all ADCs, then timing error is reduced, but the S/H circuit must have very high speed sampling frequency and very accurate circuit
Solution Approach 1:
Instead of using complex S/H circuits to actively reduce timing errors, the patent employs a passive approach where the timing errors are naturally preserved in the DC components of ADC outputs. The system then uses these preserved errors as information sources for estimation, eliminating the need for complex corrective circuitry.
Solution Approach 2:
The patent replaces the mechanical/electrical approach of using high-speed S/H circuits to correct timing errors with a computational approach. By substituting complex analog circuitry with simple digital averaging operations, the system achieves timing error reduction without requiring high-speed sampling circuits.
Data Source
AI summary
The present invention provides an apparatus and a method for estimating at least one of timing, gain, and offset errors of a time-interleaved ADC. The apparatus has a first ADC, a second ADC, a converter, an estimator, and a compensator. The converter has a Fourier Transform converter and a calculator.