Dear Sam, obviously there is nothing special in 50 ohm or 60ohm or whatevere value SI theory and practice are based upon Maxwell equation and its semplified form Trasmission line equation that simply works for any impedance value .... Giancarlo -----Messaggio originale----- Da: si-list-bounce@xxxxxxxxxxxxx per conto di Sam Pete Inviato: mer 20/12/2006 7.27 A: si-list@xxxxxxxxxxxxx Oggetto: [SI-LIST] Transmission line impedance Hi Friends, Whenever we refer to SI books or application notes, the impedance of the transmission line is mentioned as 50-ohms or 60-ohms. What is the speciffic reason behind this value? why can't it be something different than this? OR Why this 50-ohms conceptualized from the driver's perspective? (evolution of transmission line theory for Digital Design) Please flood me some info on this. Regards, Sam __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://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: //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 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