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Re: 8b/10b and EMI

Kamran, Rick, and All,

As far as EMI by idle pattern is concerned, I don't believe the way 
in IEEE1394b is a good idea for XAUI.  However, it may be worth to 
consider data, not idle, scrambling before 8b/10b coding if the 
repetitive input data patterns such as all zeroes are problem as 
Rick has pointed out.

As I understand, IEEE1394b requires some kind of training sequence 
with K28.5 to establish byte syncronization.   Once the training is 
completed, data and idle are scrambled and then encoded to 10b, 
where D28.5 is always replaced by K28.5 to enable byte syncronization 

It's my knowledge from the pre-mature draft doccument.  Please 
let me know if this is obsolete.


At 2:49 PM -0500 00.3.17, Kameran Azadet wrote:
> 	this was actually not my proposal, but apparently (I heard this 
> from Pat Thaler and Dave cunnigham mentioned it in a recent email), this
> is being used in IEEE 1394b, and also may be used in infiniband. I
> don't know how the idles are treated (as opposed to data). 

At 2:42 PM -0800 00.3.17, Rick Walker wrote:
> The problem is also with repetitive input data patterns, such as all
> zeroes, or all ones.  Such patterns are very common in computer data
> transmisssion. 

Osamu Ishida
NTT Network Innovation Laboratories
TEL:+81-468-59-3263 FAX:+81-468-55-1282