FreeLists / si-list / [SI-LIST] Re: Passivity/Causality

["Hargin, Bill" <bill_hargin@xxxxxxxxxx>]

Hi Ria:

In the digital SI world, Scattering Parameter (aka: S-Parameter;
Touchstone) models are often used to describe passive parts of an
interconnect.  (E.g., package models, connectors, vias, typically any
part of the channel that's passive, or even an entire backplane.)

Causality: In these S-Parameter or Touchstone models, you can't have an
effect that precedes its cause. (E.g., the lights turning on before
you've thrown the switch.)

Passivity: A passive S-Parameter interconnect model cannot create
energy. =20

Checking a model for passivity and causality is another (longer)
discussion.  Mentor users (HyperLynx, ICX, ICX Pro) are provided with
something we call the Touchstone Viewer, which allows them to check a
model for passivity and causality, among a number of other things. =20

Bill Hargin
High-Speed Marketing Manager
Mentor Graphics Corp.
Systems Design Division
425-301-4425 - Mobile=20

=20

> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx=20
> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Ria R
> Sent: Thursday, December 06, 2007 9:58 PM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Passivity/Causality
>=20
> Gurus,
>   I have heard these 2 terms alot in the world of SI:=20
> Passivity and Causality.
>   I tried googling it and I dont seem to get what I am lookimg for.
>  Can someone please throw some light on the definitions of=20
> these 2 terms and what significance they have in Signal Integrity?
> Thanks in advance,
> Best Regards,
>=20
> Ria.
>=20
>=20
>      =20
> ______________________________________________________________
> ______________________
> Looking for last minute shopping deals? =20
> Find them fast with Yahoo! Search. =20
> =
http://tools.search.yahoo.com/newsearch/category.php?category=3Dshopping
>=20
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>=20
> or to administer your membership from a web page, go to:
> http://www.freelists.org/webpage/si-list
>=20
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>=20
>=20
> List technical documents are available at:
>                 http://www.si-list.net
>=20
> List archives are viewable at:    =20
>               http://www.freelists.org/archives/si-list
> or at our remote archives:
>               http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
>               http://www.qsl.net/wb6tpu
>  =20
>=20
>=20
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field


List technical documents are available at:
                http://www.si-list.net

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu