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IBIS INTERCONNECT MODELING AD HOC TASK GROUP MEETING MINUTES
Meeting Date: October 17, 2006

http://www.eda.org/ibis/adhoc/interconnect/

Attendees:
----------
(* denotes present)
Agilent                    - Sanjeev Gupta* 
Green Streak Programs      - Lynne Green 
Intel                      - Michael Mirmak*
Mentor Graphics Corp.      - John Angulo*
Micron Technology          - Randy Wolff
Sigrity                    - Sam Chitwood 
Teraspeed Consulting Group - Bob Ross* 

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Next Meeting:
TBD
               Telephone     Bridge   Passcode
              916-356-2663       

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Michael began the meeting by summarizing the objectives of the 
interconnect ad hoc group:

1) complete ICM-IBIS linking BIRD and any associated changes to the 
   ICM specification
2) update the ICM specification, if needed, to clarify the mapping of 
   ICM nodes to S-parameter ports
3) complete a specification for "Touchstone Plus" or similar 
   industry-standard definition for Touchstone-like files, to include 
   complex impedance references, removal of limits on the maximum number 
   of ports and per-port impedance references 

He noted that Sam Chitwood of Sigrity had provided several presentations
showing the issues with Touchstone as currently implemented in the ICM 
specification.  Bob Ross of Teraspeed has also provided some documents 
showing alternatives to how S-parameters are linked to nodes in ICM.

Bob suggested that the efforts to create a new non-proprietary S-
parameter format might be decoupled from other ICM-related efforts.  

Sanjeev stated that the "MDIF" format might be a better alternative to 
expanding Touchstone.  He noted that this format can support a wide 
variety of data and should accommodate ICM's needs.

Michael reviewed his draft text for an IIRD to clarify how S-parameter 
ports link to nodes.  Most of the text simply removes any use of the 
word "port" where S-parameters are not concerned, and explains that 
ports may be non-physical, unlike terminals or nodes.  The IIRD 
permits ports to have either explicit individual references or a 
single reference for the entire family of ports.

Bob stated that he believed the examples in the ICM specification to be 
correct, where 8 individual nodes are named for a 4-port network.  Each 
port is assumed to consist of two nodes, though he objects to Michael's 
use of the terms "reference," "positive" and "negative" regarding these 
ports.  In all cases, N S-parameter ports must result in links to 2N 
nodes or terminals. 

Sanjeev raised some objections, in that this assumption may not be 
explicit in the Touchstone documentation.  Further discussion showed 
that ports, nodes and terminals, as terms, were not understood the 
same way between the participants.

Sanjeev was asked to come up with more explicit port definitions based 
on documents he can make public.  Both he and Bob were asked to show 
some sort of diagram, perhaps in a single slide, to show how they 
believed the mapping to work.  Michael will schedule the next meeting to 
accommodate Sam Chitwood, Randy Wolff and the other unavailable 
participants.

ARs
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Sanjeev/Bob - provide separate simple diagrams to show how port 
              definitions actually work in Touchstone; comments on node
              mapping are welcome