Let's be a little more clear about the situation we are discussing. For = stripline I would expect (due to cancellation) NEXT to be greater than = FEXT. BUT! Charles asked about two MICROSTRIP traces. Anyone want to claim the = inductive and capacitive coupling for microstrip traces is sufficiently = balanced for cancellation to apply? Aubrey Sparkman=20 Enterprise Engineering Signal Integrity Team Dell, Inc.=20 Aubrey_Sparkman@xxxxxxxx=20 (512) 723-3592 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of Yuming Cheng Sent: Tuesday, November 29, 2005 11:29 PM To: Charles.Grasso@xxxxxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] ??: NEXT and FEXT: Question on relative levels Hello Charles, From figure 3.2 of "High-Speed Digital System Design=A1=AAA Handbook of = Interconnect Theory and Design Practices", you can find that the = inductive and capacitive crosstalk cancel at far end and reinforce at = near end. You can also get this from section 5.7.1-5.7.3 in "High-speed digital = design, Dr. Johnson". =20 So it's possible to have NEXT greater than FEXT. B.R. Astrom --- "Grasso, Charles" <Charles.Grasso@xxxxxxxxxxxx>=D0=B4=B5=C0: > Is it possible to have NEXT greater than FEXT.?? > =20 >=20 > For example: For a two trace microstrip system my simulator reports=20 > 10% NEXT (so for a 2.5V signal that translates to 250mV). >=20 > Based on the reported mutuals and self numbers and using the formula=20 > in Eric's book I estimate 60mV for FEXT. >=20 > =20 >=20 > Is this reasonable? >=20 > =20 >=20 > Best Regards > Charles Grasso > Senior Compliance Engineer > Echostar Communications Corp. > Tel: 303-706-5467 > Fax: 303-799-6222 > Cell: 303-204-2974 > Pager/Short Message: 3032042974@xxxxxxxx > Email: charles.grasso@xxxxxxxxxxxx; > Email Alternate: chasgrasso@xxxxxxxx >=20 > =20 >=20 >=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: > //www.freelists.org/webpage/si-list >=20 > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field >=20 > List FAQ wiki page is located at: > =20 > http://si-list.org/wiki/wiki.pl?Si-List_FAQ >=20 > List technical documents are available at: > http://www.si-list.org >=20 > List archives are viewable at: =20 > //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 =09 =09 =09 ___________________________________________________________ =D1=C5=BB=A2=C3=E2=B7=D1G=D3=CA=CF=E4=A3=AD=D6=D0=B9=FA=B5=DA=D2=BB=BE=F8= =CE=DE=C0=AC=BB=F8=D3=CA=BC=FE=C9=A7=C8=C5=B3=AC=B4=F3=D3=CA=CF=E4 http://cn.mail.yahoo.com ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: =20 //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 ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //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