Exactly correct. This is the 3 dB bandwidth for a circuit dominated by a single pole, based on a 10% to 90% Tr measurement. For 20% to 80% measurements (found on many logic data sheets), use BW ~ .22/Tr. In the instance of an infinite pole, all pass filter a.k.a coax cable, I've read that BW ~ .31/Tr (10% to 90%). Can anyone clarify the origin of THAT number? Thx in advance, Orin On Mon, 7 May 2007 11:21:55 -0400 jaudet@xxxxxxxxxx writes: > Based on simple RC circuit... Vo=V*(1-e^(t/RC)) > So apply it for 10% and 90% ( risetime ) > Vo at 0.1= 0.1*V = 0.1*(1-e^(t at 0.1/(RC)) > Vo at 0.9= 0.9*V = 0.9*(1-e^(t at 0.9/(RC)) > > tr= t at 0.9 - t at 0.1..... and by manipulation on previous > equations > you will find tr = 2.2RC > > fc= 1/ (2piRC).... > > so fc = 0.35/tr > > > Jean Audet > Electrical Analysis > STG / World Wide Packaging & Test > Organic and Ceramic Packages > IBM Bromont > Tel: 450-534-6317, tie line: 552-6317 > E-mail: jaudet@xxxxxxxxxx ------------------------------------------------------------------ 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 technical documents are available at: http://www.si-list.net 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