[BP] Signalling ad-hoc conference call minutes 9-9-04

Charles Moore reviews his presentation (http://ieee802.org/3/ap/public/signal_adhoc/moore_02_0904.pdf ). The following are comments generated during the review.

On the use of HSpice as a simulator
- Dimitri was the use of HSpice and S-parameters verified
- Fulvio the discussion should be about the technique proposed rather than a specific time-domain simulator
- Mike A given that a level of checking on S-parameters usage is performed, how key is HSpice?
- Charles not familiar with other simulators. Have been assuming that most have access to HSpice ...
- Richard M ...it is really important to verify self consistency in time and frequency domain when using S-parameters
- Mike A It would be helpful to put some notes together on how to simulate with S-parameters in the time domain
  - Richard Mellitz volunteers to do so
On the use of an interfering sinusoid
- Fulvio is the sinusoid interference test to be run at a single frequency, a set of frequencies or what?
- Charles not clear yet
On the model /block diagram
- Ali should we not been using a 64/66 pattern instead of a PRBS 2^7? What about AC coupling effects?
- Charles if someone generates it I can convert it in the appropriate format
- Ali what about the package model
  - ...discussion follows regarding the package itself, the effects of ESD protections, terminations etc.
- Mike A it is impractical for us to specify the details of Silicon and/or package implementation. The approach we are following is to specify the system from TP1, TP4 point of view.
  - ... some more discussion ...
- Charles in the end I would like to note that the more details are added to the package model, the more this becomes an impediment to the generality of the approach.
- Charles With regards to the channel model these will be provided by the Channel ad hoc ...
- Mike A ... Channel ad hoc will provide limits. This group will select the actual models to be used.
On the post-processing of the data
- Fulvio It seems that this approach is based on an architecture where the receiver equalization is done in the continuous time domain
- Charles yes, I have not considered sampled equalizers
- Mike A. how do we include imperfections/degradations introduced by timing loop, equalization loop
- Charles some of it is done in post-processing
- Fulvio but in the case of a sampled receiver the interaction between the two systems is not taken into account
- Ali especially in this kind of system where the eye is closed you need to consider that
- Fulvio so if the assumption is to decouple CDR and Receiver, how is this different then the proposal put forward last week by Bill and John Stonick?
- John S. If we just look at the eye after some equalizer with ideal timing seems the right thing to do.BER estimation inclusive of CDR effects are more complicated. Spice can not simulate worst case patterns.
- Ali the same can be said about the equalizer.
- John S. Right. So if I provide a set of coefficients (a finite number of taps and finite resolution) I can make an estimate of BER and allow quantification of time and voltage margins and allow fair comparison.
- Mike A. We need a detailed proposal on how to do so.
- John S. But is this the correct approach to the problem?
- Brain I feel that we need to concentrate on what goes on in the channel. What happens in the receiver is helpful but should not be used to specify constraints for the receiver design.
- John S. Absolutely not.
- Brian You mean that the signaling should be accompanied by a certain amount of disclosure and not by imposing constraints?
- John S. Right. We want to determine the right trade off.
- Ali What are we really trying to do here? Are we trying to set an interoperability standard?
- Mike A. The task force is now concentrating on selecting a method by which we can compare different signaling methods.
- Ali What about StatEye ?
- Steve A We did present an analysis of the synthesized channel using StatEye.
- Mike A ... non of which has been presented to the task force. The schedule and target have been now public for some time.
- Ali I am concerned about the time to develop a methodology ...
- Mike A I can ask you to present what it would take to develop a StatEye based methodology to compare signaling schemes.
- Adam As a clarification, the September deadline refers to presentation of new technical content. The decision for signaling will take place in November.
- Mike A Ali has the AR to present to this body a methodology based on StatEye.

At this point a straw poll was conducted to get a measure of the ad-hoc level of interest in Charles proposal.It is not binding and it is meant to assess whether we want Charles to fine tune the his simulation system

Yes 10
No 4
Abstained 4

John D Can we poll the "no" to see if they have alternatives:
- one abstained form doing so, while the others pointed to the proposal put forward last week.

At this point some more discussion concerning StatEye and its viability took place. The discussion was stopped by the chair who pointed out that any discussion on the subject should take place in the context of a formal presentation to avoid duplication of effort.

Next Mike introduces John D'Ambrosia presentation of Channel models. Before giving the floor to John, Adam H made the following statement: "I want to make clear that John has volunteered to provide test cases. These are not needed to be the only ones and I am soliciting other participants to bring other models for the consideration of this group"

John D'Ambrosia goes through his presentation (http://ieee802.org/3/ap/public/signal_adhoc/dambrosia_02_0904.pdf )

John D A number of pending slides will be updated and added
John D All channels presented are real channels (there is no mix and match of data from different sources)
Ali Is the resonance on TC7 due to reflection
John D Yes
Richard It would be interesting to have well behaved short channels

Meeting is ended due to time constraints. The ad hoc chair thanks all presenters and encourage the use of the reflector to keep the discussion going.