Bit Response Superposition Eye Simulation Without Noise Overcounting
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Solution Overview
Problem
High-speed chip-to-chip system level design simulations overestimate bit error rates due to overcounting of steady-state noise, particularly from non-ideal power supplies, leading to overly pessimistic eye diagrams.
Innovation Solution
Characterize and remove steady-state noise from edge responses before superposition, then add it back once during waveform generation to accurately account for its effects without overcounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If steady-state noise is included in each edge response during superposition, then noise effects are captured, but noise is overcounted leading to overestimated bit error rates
Solution Approach 1:
The patent extracts steady-state noise from individual edge responses before performing superposition. By separating the noise component from the signal component and only superimposing the signal portions, the method prevents noise overcounting while maintaining accurate noise representation in the final eye diagram through a single noise addition step.
Solution Approach 2:
The patent segments the edge response into signal and noise components. By treating these components separately during superposition—superimposing only the signal parts and adding noise only once to the final result—the method resolves the contradiction between capturing noise effects and avoiding noise overcounting.
2Measurement precision
If transient analysis is used to achieve accurate eye diagrams, then measurement accuracy is improved, but computational time increases
Solution Approach 1:
The patent performs preliminary characterization of steady-state noise separately from the edge response superposition process. By pre-characterizing the noise and preparing clean edge responses in advance, the method enables accurate eye diagram generation through efficient superposition without requiring computationally intensive transient analysis.
Solution Approach 2:
The patent replaces the computationally intensive transient analysis mechanism with a more efficient superposition-based approach. By substituting the traditional transient analysis method with a superposition method that properly handles noise, the patent achieves similar accuracy with reduced computational time.
Data Source
AI summary
A method for circuit analysis includes removing noise from an edge response of a circuit to produce a modified edge response and performing superposition of the modified edge response to generate a waveform. The method also includes adding the removed noise to the waveform to generate a noised waveform and generating, based on the noised waveform, an eye diagram for the circuit.