Transmission Device Impedance Compensation for Differential Signal Integrity
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Solution Overview
Problem
Current communication systems face limitations in enhancing communication performance due to asymmetrical differential impedances in transmission paths, leading to reduced eye opening of differential signals and increased communication errors.
Innovation Solution
The proposed solution involves adjusting the output impedance of the transmission device and input impedance of the reception device to compensate for asymmetrical differential impedances by varying the output impedance of one output terminal to be lower than the others and adjusting the input impedance of specific terminals to widen the eye opening of differential signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If asymmetrical differential impedances are used in transmission paths, then device complexity is reduced, but communication performance deteriorates due to reduced eye opening and increased errors
Solution Approach 1:
The patent applies local quality by adjusting the output impedance of specific output terminals (making the second output impedance lower than the first and third) to compensate for asymmetrical differential impedances in the transmission path. This localized impedance adjustment at the transmission device output resolves the communication performance degradation caused by asymmetrical transmission paths without requiring complete symmetry throughout the entire system.
Solution Approach 2:
The patent changes the impedance parameter of specific output terminals to compensate for asymmetrical differential impedances. By adjusting the output impedance values (making the second output impedance lower), the system compensates for transmission path asymmetries, thereby improving eye opening and reducing communication errors while maintaining practical device complexity.
2Reliability
If output impedance of second output is made lower than first output, then communication performance is improved by compensating asymmetry, but impedance matching complexity increases
Solution Approach 1:
The patent implements local quality by applying different output impedance values to different output terminals specifically to compensate for known asymmetrical differential impedances in the transmission path. This targeted approach improves communication performance by addressing only the specific impedance mismatches that affect signal integrity, rather than requiring uniform impedance matching across all terminals.
Solution Approach 2:
The patent deliberately introduces asymmetry in the output impedance configuration (making the second output impedance lower than the first and third outputs) to counterbalance the asymmetrical differential impedances present in the transmission path. This controlled asymmetry in the output stage compensates for the asymmetry in the transmission medium, thereby improving overall system performance and eye opening.
Data Source
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AI summary
Provided is a transmission device including a transmitter. The transmitter includes a first output, a second output, and a third output, and is configured to transmit a symbol signal corresponding to a combination of signals of the first output, the second output, and the third output. An output impedance of the second output is lower than an output impedance of the first output.