Worst-Case Data Eye Determination for Serial Link Simulation
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Solution Overview
Problem
Designing high-speed serial interconnect systems is challenging due to the difficulty in determining the worst-case data eye size, which is affected by inter-symbol interference, reflections, crosstalk, and jitter, making it hard to simulate effectively within a reasonable time frame using conventional methods.
Innovation Solution
A method and system that determine the worst-case data eye by analyzing the effects of data patterns and jitter on a victim and aggressor channels, minimizing parameters like amplitude and transition points, and combining these effects into a cumulative data eye pattern, allowing for efficient simulation and computation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional simulation methods are used to analyze all permutations of distortion sources (inter-symbol interference, reflections, crosstalk, jitter), then measurement precision of worst-case data eye is improved, but loss of time increases significantly
Solution Approach 1:
The patent segments the distortion analysis into independent components: inter-symbol interference (ISI) analysis, reflection analysis, crosstalk analysis, and jitter analysis. Each component is analyzed separately using targeted test patterns, and the results are combined to determine the worst-case data eye. This segmentation avoids the need to simulate all permutations of distortion sources simultaneously, dramatically reducing simulation time while maintaining accuracy.
2Reliability
If all possible data patterns and distortion combinations are simulated to ensure reliability, then reliability of worst-case determination is improved, but device complexity increases
Solution Approach 1:
The patent employs preliminary actions by using specific pre-designed test patterns tailored to excite each distortion mechanism independently. For example, periodic patterns are used for ISI analysis, specific bit sequences for reflection analysis, and controlled patterns for crosstalk and jitter analysis. These preliminary test patterns are designed to isolate and measure each distortion component's effect on the data eye, ensuring reliable worst-case determination without requiring complex full-permutation simulations.
3Manufacturing precision
If comprehensive distortion analysis including all interaction effects is performed, then manufacturing precision of channel design is improved, but productivity decreases due to extended analysis time
Solution Approach 1:
The patent segments the comprehensive distortion analysis into independent modular tests for each distortion mechanism (ISI, reflections, crosstalk, jitter). Each segment uses optimized test patterns and analysis methods specific to that distortion type. The results from each segment are then combined to assess the overall channel performance. This modular approach maintains high manufacturing precision for channel design while significantly improving productivity by reducing the total analysis time compared to exhaustive simulation methods.
Data Source
AI summary
A serial link system is provided for determining a worst-case cumulative data eye. The system includes a transmitter, a receiver, and a channel between the transmitter and receiver such that data sent by the transmitter is received by the receiver through the channel. The channel includes a plurality of connections including a victim and at least first and second aggressors, with the victim being disposed between the first and second aggressors. The system also includes a controller constructed and arranged to determine a worst case cumulative data eye based on a data pattern of the victim, jitter on the victim, an effect a data and jitter pattern on the first aggressor has on the victim and an effect a data and jitter pattern of the second aggressor has on the victim and to combine the effects of the data pattern of the victim, the jitter on the victim and the effects of the first and second aggressors on the victim into a single pattern to determine cumulative data eye for use in a simulator.