Ron:


With proper parameters, the .W model works very well. Look on the nesa
web site for applicable papers.


ed sayre

==========================================================

At 11:26 AM 12/10/99 -0800, you wrote: 

>>>>

<excerpt>Hi Brad 


I am using HP ADS a frequency domain simulator with Impulse, a real time
convolution 

to the time domain with time domain models mixed in.  I started using
this because of the 

problem with spice not modeling frequency dependent losses properly for
some cable losses. 


The ADS simulations matched the measured results very nicely.  However,
the problem 

with ADS is that the simulations take a long time to run when converting
back to the time 

domain, so they are a bit slow and expecially when having large spice
circuits driving and 

receiving the signals. 


My question is, does the W element simulations closely match the measured
results of 

 cable and long PCB traces? 


Thanks 


Ron Miller 


Bradley S Henson wrote: 

<excerpt>Let me further propose we discuss the overall reliability of all
of our tools 

and techniques for gigabit digital. Like many of you, I found out the
hard way 

that the old HSPICE models (prior to "W" elements) could be very wrong at 

microwave frequencies. Consequently, I think we all need to question, and 

discuss, the efficacy of our present SI tools and techniques. We need to
all be 

thinking about including frequency dependent dielectric as well as
conductor 

losses. SI tools that use lossless approximations break at these rates,
etc. 

Could make for some fun since many of us are already out on the edge
dealing 

with multiboard bit rates in the GHz range. Hey, even the dreaded trace 

corner-mitering topic has a completely new context for 2GHz digital rates
;) For 

the sake of the list, we'll leave that one lay... 


Brad Henson, Engineering Fellow 

Raytheon Systems Co. 


"zanella, fabrizio" <<zanella_fabrizio@emc.com> on 12/08/99 01:21:45 PM 


Please respond to si-list@silab.eng.sun.com 

  

  

  

  

  

  


 To:      "'SIList'" <<si-list@silab.eng.sun.com> 


 cc:      (bcc: Bradley S Henson/RWS/Raytheon/US) 

  

  


 Subject: [SI-LIST] : IBIS models at Gbit speeds 

  


     > Hello SI engineers, 

     > Does anyone have experience using IBIS models to simulate serial 

signals at 

     > frequencies of 1GHz and above?  I have an IBIS model for a SERDES 

device, 

     > and I'm concerned about its behavior and accuracy at these 

frequencies. 


     > Thanks and regards, 

Fabrizio Zanella 

Hardware Engineering 

EMC Corporation 

508-435-2075, x14645 

FAX: 508-497-8027 

fzanella@emc.com 


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</excerpt>--&nbsp;

Ronald B. Miller&nbsp; _\\|//_&nbsp; Signal Integrity Engineer

(408)487-8017&nbsp;&nbsp;&nbsp; (' 0-0 ')
fax(408)487-8017&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp; ==========0000-(_)0000===========&nbsp;

Brocade Communications Systems, 1901 Guadalupe Parkway, San Jose,
CA&nbsp; 95131

rmiller@brocade.com,&nbsp; rbmiller@sjm.infi.net  

</excerpt><<<<<<<<








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|       NORTH EAST SYSTEMS ASSOCIATES, INC.       |

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|     "High Performance Engineering & Design"     |

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| NESA, Inc.              http://www.nesa.com/    |

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