Binchuan & Dr. Zheng, My two cents: Generally, you'll introduce more radiated emission from (the odd mode of ) the differential pair and more odd mode noise on the differential pair receiver by removing the ground, even you can keep the differential impedance, I think. A differential pair receiver does care the odd mode noise, but not the even mode noise, unless the even mode noise has much high level (e.g. Surge). Regards, Fred Wen > -----Original Message----- > From: Jian X. Zheng [mailto:jian@xxxxxxxxxx] > Sent: Saturday, July 27, 2002 12:38 AM > To: binchuan2000@xxxxxxxxxxxx; si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Re: Remove Ground underneath Differential > signal is deserved or not? > > > > Hi, Binchuan: > > Removing the ground plane for differential pair will suppress > the even mode. > Basically, the even mode will not be propagating. Its energy > will not be > transmitted. The even mode signal, which is considered as > noise, will be > reduced in your circuit. Thanks! > > Best regards, > > -------------------------------------------------------------- > --------- > Jian-X. Zheng, Ph.D > Zeland Software, Inc., 48890 Milmont Drive, 105D, Fremont, CA > 94538, U.S.A. > Tel: 510-623-7162, Fax: 510-623-7135, Web: http://www.zeland.com > --------------------------------------------------------------------- > > > -----Original Message----- > > From: si-list-bounce@xxxxxxxxxxxxx > > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of binchuan2000 > > Sent: Thursday, July 25, 2002 7:20 PM > > To: si-list@xxxxxxxxxxxxx > > Subject: [SI-LIST] Remove Ground underneath Differential signal is > > deserved or not? > > > > > > > > I am confused that I read some book about remove Ground under > > Differential could reduce the induced Current from > Differential pair, > > but the question is how we could control its impedance(Differential > > impedance) although Differential doesn't reference to Ground. If I > > follow this content to REMOVE Ground under Differential pair how > > could I control its Zodd impedance and its Zdiff impedance. Does it > > will generate any other problem and if it does, why some textbook > > advise it? > > > > Remove Ground is worth or not for Differential signal ? > > > > > > > > Thanks, > > > > > > > > Binchuan.Wang > > > > ------------------------------------------------------------------ > > 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 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 > > > > > > ------------------------------------------------------------------ > 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 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 > > ------------------------------------------------------------------ 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 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