# RE: [SI-LIST] : What's your favourite Screwy SI Concept?

From: ARNOLD,PETER (HP-Cupertino,ex3) ([email protected])
Date: Fri Jan 14 2000 - 16:37:45 PST

BTW, Anyone who doubts the power of simple but erroneous ideas to propagate
themselves should consider the widespread belief that the new millenium
began this year. Despite constant refutation this meme is ineradicable.

pma.

-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Friday, January 14, 2000 4:08 PM
To: [email protected]; [email protected]
Subject: RE: [SI-LIST] : What's your favourite Screwy SI Concept?

Man, you guys blow me away! You want data? Check out UltraCAD and see
what Doug Brooks says and has data to back it up. I have NEVER seen any
data dissproving 90 degree traces. It's always heresay! Some days are
just better than others!

Mitch

---------Included Message----------
> Date: Fri, 14 Jan 2000 11:10:25 -0800
> From: "Jian Zheng" <[email protected]>
> To: <[email protected]>
> Subject: RE: [SI-LIST] : What's your favourite Screwy SI
Concept?
>
> Hi:
>
> In fact, the flow of electric current is very similar to the flow
of water
> current.
>
>
> | |
> | |B______
> |
> |A__________
>
> When you have a bend, the current will take a short cut at the
corner B. The
> current at the corner A will be slowed down. For the electric
current, the
> slow down at corner A will create reflection from the corner. The
short cut
> at the corner B will make the electric path shorter than measured
along the
> center line. For standard PCB, the reflection from the corner is
very small.
> However, I understand that the electrical length is very
important in clock
> synchrinization. Accumulation of the shortening of electrical
path at angles
> may have effect to SI. Thanks!
>
> Best regards,
>
>
----------------------------------------------------------------------------
> ------------
> Jian-X. Zheng, Ph.D
> Zeland Software, Inc., 39676 Mission Blvd., Fremont, CA 94539,
U.S.A.
> Tel: 510-797-8109, Fax: 510-797-8241, Web: http://www.zeland.com
>
----------------------------------------------------------------------------
> ------------
>
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]]On Behalf Of Jeff
Seeger
> > Sent: Friday, January 14, 2000 10:05 AM
> > To: [email protected]
> > Subject: Re: [SI-LIST] : What's your favourite Screwy SI
Concept?
> >
> >
> > Tom Dagostino wrote:
> > >
> > > Bending a wire keeps a uniform cross section. Putting a
corner
> > in a trace
> > > adds extra C at the corner from a larger area.
> > >
> > And herein lies the arguement, I believe.
> >
> > Perhaps those who argue against "right angles" envision a
> > geometry where the line has a squared corner both on the
> > inside of the elbow and the outside.
> >
> > I would wager that those who claim no material effect are
> > working with the usual CAD system/photoplotter geometry of
> > a squared corner inside the elbow and a radiused one on the
> > outside.
> >
> > An attempt at ascii art:
> >
> > "Right Angle" "Standard Practice"
> >
> > \ \ \ \
> > \ \ \ \
> > > > > )
> > / / / /
> > / / / /
> >
> > HTH,
> > --
> >
> > Jeff Seeger Applied CAD Knowledge
Inc
> > Chief Technical Officer Tyngsboro, MA
01879
> > jseeger "at" appliedcad "dot" com 978 649
9800
> >
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> >
> >
>
>
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