DC-Balance Data Preamble for Simultaneous Switching Noise Reduction

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Solution Overview

Problem

As data transmission speeds increase, existing DC balance coding systems like 8B/10B face challenges in minimizing Simultaneous Switching Noise (SSN) caused by parasitic inductances, which can degrade signal quality and system performance.

Innovation Solution

Incorporating a preamble of dummy data that creates an intermediate level of SSN, either fixed or variable, to precede the DC balance encoded data, reducing the maximum SSN generated by the encoded data during transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If DC balance encoded data is transmitted without preamble, then data transmission speed is maintained, but Simultaneous Switching Noise (SSN) increases due to large current variations

Engineering Contradiction:

ImproveSimultaneous Switching NoiseVSAvoiddata transmission speed

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

A preamble of dummy data is transmitted before the actual DC balance encoded data to pre-condition the transmission line and reduce the magnitude of current variations when the actual data begins. The preamble creates an intermediate current level that lessens the shock transition to the full data transmission current, thereby reducing SSN without significantly impacting overall transmission speed.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If a preamble of dummy data is transmitted, then Simultaneous Switching Noise is reduced, but transmission time increases

Engineering Contradiction:

ImproveSimultaneous Switching NoiseVSAvoidtransmission time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

Instead of transmitting a full data word as preamble, only a partial preamble (fewer bits) is transmitted. This partial action is sufficient to reduce the magnitude of current variations and SSN, while minimizing the additional transmission time. The preamble length is optimized to provide just enough noise reduction without excessive time penalty.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If DC balance encoding is used, then clock recovery is facilitated, but circuit complexity increases

Engineering Contradiction:

Improveclock recoveryVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The transmission is segmented into two parts: a preamble portion and a data portion. The preamble uses simplified encoding with fewer constraints, while the main data portion uses full DC balance encoding. This segmentation allows the system to benefit from clock recovery during data transmission while reducing the overall encoding complexity by not applying full DC balance rules to the preamble.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS7492288B2Transmitting/receiving methods and systems for DC balance encoded data including simultaneous switching noise reducing preambles

Publication Date: 2009.02.17 SAMSUNG ELECTRONICS CO LTD

AI summary

DC balance encoded data is transmitted by transmitting a preamble of dummy data that is configured to provide an intermediate number of bits of a given logic value that is at least one bit of the given logic value but less than a maximum number of bits of the given logic value in the DC balance encoded data, to thereby reduce the simultaneous switching noise that is caused by transmission of a first word of DC balance encoded data. The preamble may contain one or more words of fixed and/or variable dummy data.