Re: BIRD #61 -- Characterization of Receivers

From: Stephen Peters <sjpeters@ichips.intel.com>
Date: Wed Aug 18 1999 - 15:31:19 PDT

Kellee wrote:

> Well, I am concerned that about the use of the new INF reserved word in the
> receiver delay table:

  <snip>

> Often, interpolation/extrapolation is used when trying to look up values in
> tables. When INF appears in the table, doesn't it present a discontinuity in
> the data? One of the examples given showed a delay delta of 7.0ns at 1.53V
> and INF at 1.51V. What would the delta delay be at 1.52V? Where is the elbow
> in the curve? Is this simply a case of the table not having enough data
> points?
>

  The simple answer is yes -- the intent of the example was to show syntax
rather than real data. A realistic example would have many more point around
the input threshold point of the buffer. However, it seems to me that the
use of the INF value cannot be avoided completely. Does this mean a
behavioral receiver model based on table lookup becomes impractical, or does
it just mean that the modeler (data supplier) needs to be *really* careful
about the points picked?

   Regards,
   Stephen Peters
   Intel Corp.
Received on Wed Aug 18 15:37:46 1999

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