Re: Connector spec swathing

Mike,

Thanks for your illustration of my point. Clearly we have
exactly the same concern.

Gus,

Yes, including the larger matrix that is supposed to be expandable
to a full banded matrix would be useful, but it should also include
instructions on just how that smaller matrix is supposed to be used
to get the full banded matrix.

Thanks,

Chris

apanella@molex.com wrote:
>
> An important point in using a "swath".
>
> The initial swath matrix MUST be large enough (i.e. represent enough pins) such
> that the appropriate number of coupling effects can be observed.
>
> That being said... the swath was created to make a single large "matrix" out of
> a smaller "matrix". The goal being to automatically create a banded matrix.
>
> The swath really wasn't created to DIRECTLY pick a pin (or multiple random pins)
> out of a connector for simulations. (Although it might be possible, I just
> haven;'t thought it through).
>
> Would it be easier if the original matrix (assuming it is initially wide enough)
> is swathed to represent a banded matrix first ?
>
> Basically, using the small matrix, incorporating matrix symmetry, and
> disregarding a given number of coupling effects to create a banded matrix.
>
> The then resultant banded matrix would be a part of the simulation deck (not
> the original small matrix)
>
> Am I way out on this one?
>
> _gus: 630-527-4617
>
> Also, for what it is worth... for this example, I would suggest that the
> starting PIN matrix would be at least 3 x 9.
>
> ____________________Reply Separator____________________
> Subject: Re: Connector spec swathing
> Author: Mike LaBonte <mikelabonte@cadence.com>
> Date: 6/14/00 10:38 AM
>
> I would like to add an illustration of Chris Reid's point, as I see it.
> Here is an ASCII picture of a connector. The pins marked as 'X'
> are those carrying the signals that the simulation product has
> determined MUST be characterized and simulated. The '0' pins are
> the other pins of the connector:
>
> 0 0 0 0 0 X O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> 0 0 0 0 X 0 0 0 0 0 0 0 X 0 0 0 0 0 0 0 0
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 X 0 0 0 0 0 0
>
> Assume that the connector model uses a 3x3 swath with 1 left edge
> and 1 right edge (5x3 total matrix size). Here is one possible
> pattern for using the swath, where 'M' represents matrix middle pins,
> and 'E' represents pins in an edge column, which must be terminated
> by Cn_Z. The '?' pins are those that could be either an edge or a
> middle, depending on which nearby swath it is considered to be "in":
>
> 0 0 E M M X E 0 0 0 E M M ? ? M M E 0 0 0 0
> 0 0 E M X M E 0 0 0 E M X ? ? M M E 0 0 0
> 0 0 E M M M E 0 0 0 E M M ? ? X M E 0 0 0 0
>
> There is no single swath that can contain the 2 pins on the right.
> But 2 swaths, each centered around one pin, will overlap. Most likely
> the simulator will have to make some choice that does not fulfill the
> intent of the model developer. Even the 2 pins on the left have some
> ambiguity; I chose the pin in the middle row as my center point, but
> the choice is not always obvious.
>
> On the subject of centering a swath around a pin, a swath with an even
> number of columns has four possible locations, giving four possible
> simulation results, depending on which is chosen. This is because the
> swath has no pin at the center, but has 4 pins equally close to the center.
>
> Since simulators have to handle a full matrix anyway, I would have to
> join Chris Rokusek in hoping for a solution that turns a connector model
> into a full matrix.
>
> Mike LaBonte
> Cadence
> <SNIPPED to save BW>
Received on Wed Jun 14 09:15:59 2000