Test Apparatus for Multichannel Eye Opening Measurement
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Solution Overview
Problem
Conventional test apparatuses face challenges in performing mass production tests for device under test (DUT) due to the need for multiple oscilloscopes and processors, which result in long processing times and dead bands during signal measurement, especially when measuring multichannel signals.
Innovation Solution
A test apparatus with multiple measuring units that generate multi-strobe signals with different phases to remove dead bands and over-sample signals, allowing simultaneous measurement of multiple signals, and includes a level comparing section, acquiring section, expected value comparing circuit, and threshold control to determine eye opening compliance with predefined eye masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional separate measuring devices like sampling oscilloscopes are used for mask tests, then measurement accuracy is maintained, but device complexity and processing time increase significantly
Solution Approach 1:
The patent combines multiple oscilloscope functions into a single measuring device by integrating a level comparing section that simultaneously compares signal levels against multiple thresholds (upper and lower eye mask limits) and an acquiring section that captures measurement data. This merging eliminates the need for multiple separate oscilloscopes while maintaining measurement accuracy through hardware-based parallel threshold comparison.
Solution Approach 2:
The patent segments the measurement process into distinct functional sections: a level comparing section that handles threshold comparison, an acquiring section that captures data, and an expected value comparing circuit that validates results. This segmentation allows each component to perform its specific function efficiently, reducing overall device complexity while maintaining precision.
2Measurement precision
If signal waveforms are measured by equivalent sampling, then measurement detail is improved, but measurement time increases significantly
Solution Approach 1:
The patent replaces the mechanical equivalent sampling process with a hardware-based level comparison system. Instead of sequentially sampling and reconstructing waveforms, the level comparing section directly compares the input signal against preset thresholds in real-time, generating logical values that indicate whether the signal exceeds upper or lower limits. This substitution eliminates the time-consuming equivalent sampling process while maintaining measurement detail through direct threshold detection.
3Productivity
If multichannel mask tests are performed in parallel, then productivity is improved, but device complexity and density requirements increase
Solution Approach 1:
The patent designs a universal measuring device that can perform multiple functions: it measures eye opening degree by comparing signals against upper and lower thresholds, performs mask tests by validating logical values against expected values, and handles multiple channels through the parallel capability of the level comparing section. This multi-functionality allows a single device to replace multiple specialized instruments, improving productivity without increasing overall system complexity.
Data Source
AI summary
Provided is a test apparatus for testing a device under test, including: a level comparing section that receives a signal under test output from the device under test and outputs a logical value, the logical value indicating a comparison result obtained by comparing a signal level of the signal under test with preset first threshold and second threshold; an acquiring section that acquires the logical value output from the level comparing section, according to a strobe signal supplied thereto; an expected value comparing circuit that determines whether the logical value acquired by the acquiring section corresponds to a preset expected value; and a threshold control section that sets an upper limit and a lower limit of a voltage of the eye mask to the level comparing section as the first threshold and the second threshold, when an eye mask test is performed for determining whether an eye opening of the signal under test is larger than a predefined eye mask.