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https://designers-guide.org/forum/YaBB.pl Design >> High-Speed I/O Design >> Looking for study report on 128b/130b coding https://designers-guide.org/forum/YaBB.pl?num=1280450713 Message started by neoflash on Jul 29th, 2010, 5:45pm |
Title: Looking for study report on 128b/130b coding Post by neoflash on Jul 29th, 2010, 5:45pm Hi, PCI-E is adopting 128/130 coding to replace 8b/10b encoding. I'm looking for materials studying the code performance, such as transition density, DC balancing, maximum run length... Thanks for the sharing of the information. Neo |
Title: Re: Looking for study report on 128b/130b coding Post by casual on Jul 30th, 2010, 12:40am I think the similar theories of 8B10B may be applied to 128B/130B to achieve dc balance. The 2 preamble bits is used as sync payload. But the max run length / data density depends on data scrambler. That means the CDR will be more challenging! It has more DC wander, thus it needs larger CDR bandwidth (around 5-10MHz). On the other hand to reduce jitter (clk), Tx/Rx PLL bandwidth must be reduced. |
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