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Re: [10GBT] PAM12 performance

Scott, Sailesh;

Can I ask for a little help here? I am having a hard time with the following two phrases.

Scott says;
>   At the risk of repeating myself, none of this changes the
> fundamental fact
> that it has been clearly shown that the PAM-8 and PAM-12
> proposals have
> similar performance (slight edge for PAM-12), but the PAM-12
> proposal offers
> the advantage of a reduced operating frequency resulting in
> reduced power
> and reduced implementation difficulties.

Sailesh says;
> a). PAM8 has 3.9dB better susceptiibilty penalty than PAM12
> over a 0m cable.
> b). PAM8 has 3.2dB better susceptibility penalty than PAM12
> over a 55m Cat-6
> cable (existing Cat-6 cabling), c). PAM8 has 2.0dB better
> susceptibility
> penalty than PAM12 over a 100m Cat-6 cable (new Cat-6  cabling).

Dan reads;

PAM12 is slightly better than PAM8, but PAM8 is at least 2.0dB better than PAM12!!!

Even worse, that difference could be substantial if we are close to a regulatory or functional limit.

Please... for those of us who really don't like conundrums, would you figure out a way to come to an agreement on the numbers? Either one is better, or the other, but both can't be "better than the other".

If it turns out that PAM8 has better theoretical performance, but PAM12 is easier implemented and more likely to engender broad support... I can understand that. But both having better performance is too puzzling for me.