Kevin, I believe that the 20 GHz spec is the receiver sensitivity. The 30ps rise time is the edge transmitted by the TDR. Regards, Chris White Christopher White | Senior Engineer | SPPDG | 507-538-5480 | white.christopher1@xxxxxxxx Mayo Clinic | 200 1st St. SW | Rochester, MN 55905 | http://www.mayo.edu/sppdg -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Kevin Li Sent: Tuesday, September 13, 2011 9:50 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] rise time and bandwidth Hi, experts, I am new to this field and I get a question for you guys. I saw a formula saying BW=0.35/Trise. So for a TDR module with 30ps rise time I should get a BW of 11.67GHz. Am I correct on this? I saw from a TDR spec that for 30ps rise time, the BW was 20GHz. That confused me. Thanks. Kevin ------------------------------------------------------------------ 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 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 technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu