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IBIS INTERCONNECT MODELING AD HOC TASK GROUP MEETING MINUTES AND AGENDA

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

Mailing list: ibis-interconn@freelists.org

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Next Meeting
Wednesday, July 9, 2008
9 AM US Pacific Time

               Telephone     Bridge   Passcode
              916-356-2663     5      477-3103

Use the LiveMeeting Links in Outlook or the information below:

      Meeting ID:       69f95fa5793942429e8d5957cb3ea410
        Entry Code:     FQwDbL29k
        Location:
meet:sip:michael.mirmak@intel.com;gruu;opaque=app:conf:focus:id:69f95fa5793942429e8d5957cb3ea410%3Fconf-key=FQwDbL29k

      http://tinyurl.com/5f577r

Agenda:
- Call for patents
- Opens
- Touchstone 2.0/3.0 Updated Text, Continued
  * Mixed-mode support
  * Wrapper or no?

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Minutes from June 25:

Attendees:
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(* denotes present)
Agilent                    - Radek Biernacki*, John Moore, Ken Wong
Ansoft                     - Denis Soldo
Cadence Design Systems     - Terry Jernberg*, Brad Griffin
Green Streak Programs      - Lynne Green
Hewlett-Packard            - Rob Elliott
Intel                      - Michael Mirmak*
Mentor Graphics Corp.      - John Angulo*, Vladimir Dmitriev-Zdorov*
Micron Technology          - Randy Wolff
Sigrity                    - Sam Chitwood*, Raymond Y. Chen, Tao Su,Brad Brim*
SiSoft                     - Walter Katz*
Teraspeed Consulting Group - Bob Ross*

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No patents were announced.   

Walter Katz raised an open issue, asking whether the original Touchstone
indicated the number of ports in the file through a keyword.  Bob Ross noted that
ICM contained such an indication, but that the original Touchstone assumed that
the number of ports could be calculated based on the total number of data points 
in the file.

Brad Brim suggested an alternative extension format for the new Touchstone: 
Z2P, for Z-parameters; S2P for S-parameters, H2P for H-parameters, etc.  
Alternately, the extension "SNP" could be used, regardless of the number 
of ports featured in the file.  Both of these would permit easy 
identification of Touchstone to file browsers/managers.  Several 
participants pointed out that associating multiple extensions with the 
same file format might prove difficult.  Radek Biernacki, Brad and Bob
explored the idea of placing the string "Touchstone" or the Touchstone 
version keyword at the very beginning of the file, even before any comments.
This would permit file browsers to recognize the file type quickly,
similarly to how many other formats are indicated to operating systems.

Review of the informal mixed-mode text continued, including examination
of an example from Michael Mirmak showing multiple terminals for a 
5-port data set.  This illustrates how referencing is left ambiguous by
the current Touchstone specification.  Vladimir Dmitriev-Zdorov pointed
out that a 7 terminal network could also be used for the same 5-port 
file, referring to a drawing he provided separately.  Brad agreed, noting
that N-1 unique voltages are provided.  Walter inquired about terminations, 
with Brad noting that all the ports are terminated in the S-parameter 
data case.  In response to additional statements, Vladimir and Radek noted
that S-parameters can include DC information (though network parameters
still apply only for steady-state conditions without time variation).  
Further ,"port" implies that current on a particular port is equal
to output currents on other ports.  This may get violated (for example,
in charge storage) and is a user problem, making how the data is used 
critical.  Radek added that network parameters are for linear circuits only,
assuming Kirchhoff's laws, and terminal/port assignment is critical to
preserving this assumption correctly.

Further discussion focused on whether port/terminal mapping should be
kept in a separate file or made part of the Touchstone data representation.  
Work to continue in the next meeting.

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Team Objectives:
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 

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