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Re: [802.3_50G] Question on precoder optionality



It is a hardware implementation in the serdes ( per single physical lane); if needed it can be optional per lane.

Anyway C2M should not have DFE; even if you have DFE the first tap is not expected to go beyond 0.5; Thus No error propagation situation .



From: Matt Traverso (mattrave)
Sent: Wednesday, August 31, 2016 7:54 AM
To: STDS-802-3-50G@xxxxxxxxxxxxxxxxx
Subject: [802.3_50G] Question on precoder optionality




In the July meeting we adopted the PMA baseline which included PAM4 precoding (detailed in hegde_3cd_01_0716). The adopted baseline presentation (nicholl_3cd_01a_0716) states “Mandatory to implement for Tx on PMAs driving backplane, copper and C2C.” & “Optional to enable (on links with dominant first DFE tap)”.


Is the intention that the precoding is “global” across all 8 physical lanes in 200/400GAUI-8?  Or can it be optional on a single physical lane on the AUI?


Or perhaps this is for further discussion…