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[BP] my plan 4 February




-- 
|--------------------------------------------------------------------|
|       Charles Moore 
|       Avago Technologies
|       Image Solutions Division
|       charles.moore@avagotech.com
|       (970) 288-4561
|--------------------------------------------------------------------|

I said that i would present my own personal proposal at next weeks meeting.
I have not settled all issues in my mind, i a still waiting for more inputs
but here is a snapshot of where i am now.  Comments welcome.

a)  Reduce channel loss:  I will propose 3dB reduction at Nyquist, and i am 
                          looking for guidance from people who know boards 
                          better for possible shape change.  I think that 
                          less than 3dB will spell grief for the Rx and more 
                          will but an intolerable burden on meeting 1m.

                          I will support a channel return loss spec as long
                          as it has some sort of smoothing of the return
                          loss.  If someone wants my help in writing such a
                          spec let me know.

                          I will support a distinction between the KR, KX4, 
                          and KX channel specs.

                          I will support some disclaimer about not making all 
                          channel impairments worst case at the same time,
                          especially if it applies mainly to KR.  If someone
                          wants help writing this let me know.

b)  Reduce crosstalk:  I will propose an integral measure of crosstalk such as
                       the power gain ratio described in brown_c1_0106.  This
                       will more accurately predict the problems caused at
                       the Rx and allow the maximum improvement in performance
                       while rejecting the minimum number of boards.  The 
                       33dB power gain ratio as calculated in moore_c1_0106
                       or the equivalent will be my target.

                       John D'Ambrosia tells me that ICR provides useful 
                       guidance to the channel designer on how to improve
                       crosstalk and it should be retained for that purpose
                       but without a specific limit.

c)  Increase EIT baseline:  If i look at abler_01_0106 and abler_c1_0106, and
                            do some eyeball interpolation (the data is too 
                            jumpy to justify anything more precise.)

       Source of Interference      EIT equivalent       sum as
           Crosstalk                   10mV               RSS
           Self Interference           10mV               RSS
           50mU p-p DCD                 7mV               Linear
______________________________________________________________________
           total                       21mV

                        So i will propose this value.

                        This assumes that the interference tolerance channel
                        has low self interference and that Agilent ITTC1016
                        is near worst case, and that my crosstalk 
                        recommendation is followed.

                        To help validate this assumption and improve 
                        repeatability of EIT, I will support a return loss
                        spec on the interference tolerance test channel which
                        is tighter than any interconnect channel return loss
                        spec.  If you want help writing such a spec let me
                        know.

d)  Convert some of jitter in EIT test to DCD:  Our test department has not 
                                                found any equipment which allow
                                                this so i will not support it.

e)  Reduced and/or modify Tx jitter:  Joe's simulations (see abler_c1_0106) 
                                      does not show any substantial benefit
                                      from a reasonable level of reduction.
                                      The burden of proof that it is cost
                                      effective will lie with any proposer.