ADC Bit Error Testing Using Symmetric Signal Self-Comparison
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Solution Overview
Problem
Existing bit error rate testing methods for analog-to-digital converters are inaccurate due to the inability to detect bit errors when both consecutive digital codes include errors, and require a varying threshold voltage that limits input signal frequency.
Innovation Solution
A signal conversion device and method that uses symmetric signal sampling and register circuits to determine bit error rate without an additional threshold voltage, by storing and shifting digital codes to exploit symmetry characteristics for self-comparison.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If threshold voltage comparison method is used to detect bit errors, then bit error detection can be performed, but consecutive errors cannot be detected when both digital codes include errors
Solution Approach 1:
The patent creates a reversed copy of the original digital code sequence by storing samples in reverse order in a second register circuit. This copied and reversed sequence is then compared with the original sequence, allowing detection of errors that would be invisible in conventional threshold-based methods. The reversal operation transforms the error pattern into a detectable difference.
Solution Approach 2:
The patent inverts the comparison approach by reversing the order of stored digital samples in the second register circuit. Instead of comparing each sample against a threshold voltage, the system compares each sample against its reversed-position counterpart. This inversion transforms undetectable consecutive errors into detectable differences, as error patterns that are identical in forward direction become different when reversed.
2Speed
If threshold voltage is increased to accommodate higher input signal frequency, then higher frequency testing is enabled, but the frequency range is limited by the need to maintain predetermined difference range
Solution Approach 1:
The patent changes the fundamental parameter being measured from absolute voltage difference (threshold-based) to relative difference between reversed sequences. This parameter transformation eliminates the need to adjust threshold voltage with frequency, as the comparison is now based on the symmetry property of the input signal rather than absolute voltage levels. The system becomes adaptable to various frequencies without requiring threshold recalibration.
Solution Approach 2:
The system uses the inherent symmetry property of the input signal to perform self-validation. By reversing the digital code sequence and comparing it with the original, the system automatically detects errors without requiring external threshold parameters. The signal's own symmetry characteristics serve as the reference for error detection, eliminating the need for frequency-dependent threshold adjustment.
Data Source
AI summary
A bit error rate testing method includes: sampling, by an analog-to-digital converter circuit, a symmetric signal to generate output digital codes; identifying a starting digital code in the output digital codes; storing the starting digital code and first digital codes, which follow the starting digital code in the output digital codes, into a first register circuit in an order as second digital codes, in which the starting digital code and the first digital codes correspond to one cycle of the symmetric signal; storing the starting digital code and the first digital codes into a second register circuit in a reversed order; shifting the starting digital code and the first digital codes in the second register circuit to generate third digital codes; and determining a bit error rate of the analog-to-digital converter circuit according to a difference between a corresponding second digital code and a corresponding one third digital code.