[ibis-macro] Re: Problem with IBIS-AMI clock_times definition

  • From: "Muranyi, Arpad" <Arpad_Muranyi@xxxxxxxxxx>
  • To: "IBIS-ATM" <ibis-macro@xxxxxxxxxxxxx>
  • Date: Thu, 18 Jun 2009 09:30:35 -0700

Mike,

On a different note, regarding:

"At a higher level, you remind us of the sad fact that in the EDA 
business, we're attempting to use a mechanism that's inherently 
quantized in time, space, and amplitude (a digital computer running a 
sampled data analysis) to create the illusion of results one would get 
from a continuous World."

I wonder about the "continuous World" statement.  As far as I
remember physics from school, everything is quantized.  But you
got me thinking here.  I can see how voltage is quantized, due
to the situation with those nasty little electrons in the atoms,
but is time and space (distance) quantized also?  Can you (or
anyone else) refresh my memory on that?

Thanks,

Arpad
=======================================================================

 

-----Original Message-----
From: Mike Steinberger [mailto:msteinb@xxxxxxxxxx] 
Sent: Wednesday, June 17, 2009 6:14 PM
To: Muranyi, Arpad
Cc: IBIS-ATM
Subject: Re: [ibis-macro] Re: Problem with IBIS-AMI clock_times definition

Arpad-

Thanks for the clarification. It helps me understand the context of your 
question, although it leaves me wondering how it is that you came to 
tackle the problem you appear to be tackling.

In particular, you seem to be assuming that the EDA platform needs to 
calculate the same clock ticks as the model, and somehow the two 
calculations are supposed to agree. In point of fact, I don't remember 
anything in the IBIS AMI spec which even mentioned having the EDA 
platform calculate any clock ticks, much less place any requirement on 
such a calculation. Furthermore, the receiver model is expected to 
contain information about the clock recovery that the EDA platform could 
not possibly have, and the receiver model expresses that information in 
the form of clock ticks. That's the only way that the EDA platform gets 
to find out about the behavior of the clock recovery algorithm in the 
first place.

You quite correctly and clearly demonstrate that two algorithms which 
mathematically should give the same result in fact do not. For the 
particular calculation you describe, I use yet another algorithm which 
yields even more precise results. In fact, I've used the same algorithm 
in at least two very different programming languages.

At a higher level, you remind us of the sad fact that in the EDA 
business, we're attempting to use a mechanism that's inherently 
quantized in time, space, and amplitude (a digital computer running a 
sampled data analysis) to create the illusion of results one would get 
from a continuous World. It can be a thankless task when our customers 
point out that the illusion didn't quite work.

Mike S.
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