Running Disparity Encoding for DC-Free High-Efficiency Links
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Solution Overview
Problem
Existing encoding methods such as 8b/10b, 64b/66b, and 64b/67b face issues with reduced transmission efficiency, failure to achieve DC-free transmission, and deterioration of run length, leading to inaccurate decoding.
Innovation Solution
An encoding device and method that scramble input data, calculate running disparities, determine whether to invert the data based on calculated disparities, and add a flag indicating the determination, ensuring controlled running disparity and run length without deteriorating transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 8b/10b encoding method is used, then transmission efficiency is reduced
Solution Approach 1:
The patent changes the encoding parameters by using 64b/66b encoding instead of 8b/10b, improving transmission efficiency from 80% to approximately 97%. Additionally, it introduces a scrambling mechanism with specific polynomial (x^16+x^12+x^5+1) and inversion control based on running disparity to maintain DC-free transmission, thus resolving the contradiction between transmission efficiency and transmission reliability.
2Productivity
If 64b/66b encoding method is used, then DC free is not achieved
Solution Approach 1:
The patent applies scrambling to the 64b/66b encoded data before transmission as a preliminary action. The scrambling process, using the polynomial x^16+x^12+x^5+1, randomizes the data sequence to achieve DC-free transmission. The system also calculates running disparity and conditionally inverts data blocks to maintain DC balance, thus achieving both high transmission efficiency and DC-free transmission.
3Reliability
If 64b/67b encoding method is used, then run length is deteriorated
Solution Approach 1:
The patent implements a feedback mechanism where the system calculates the running disparity of scrambled data blocks and uses this information to determine whether inversion is necessary. The inversion decision feedback loop ensures that run length requirements are maintained while achieving DC-free transmission. This feedback control resolves the contradiction by dynamically adjusting the transmission based on actual run length conditions.
Data Source
AI summary
Encoding devices, methods and programs that encode with high transmission efficiency by controlling a running disparity are disclosed. In one example, an encoding device includes a scrambling circuit that scrambles an input data string, a calculation circuit that calculates a first running disparity of the scrambled data string, a determination circuit that determines whether or not to invert the scrambled data string on the basis of a first running disparity calculated by the calculation circuit and a second running disparity calculated at a time point before the first running disparity, and an addition circuit that inverts or non-inverts the scrambled data string on the basis of a determination result by the determination circuit, adds a flag indicating the determination result, and outputs the data string. The technology can be applied to devices that perform SLVS-EC standard communication.