The equation is not from RC circuit. I know there will be many to explain this. But if not try to contact me. -----Original Message----- From: Lakshmi N. Sundararajan - PTU <lakshmi.s@xxxxxxxxxxx> Sent: March 6, 2010 3:59 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] frquency limit of a channel Hi Gurus, Suppose assume I have a high speed serial link at 6Gbps. The nominal rise time of the signals on this channel is 150ps. Given this rise time, the bandwidth required to transmit this signal is 0.35/tr = 2.33Ghz. So, to study this channel behavior, is it correct to only look at s-param frequency output till say 3Ghz. Can any higher frequency data points on this s-param be ignored and still correctly model the channel behavior? I also looked up BW * tr = 0.35. This equation is derived from a simple RC integrator circuit. How true can this model any channel, since we seem to be using this equation for all our studies. Please clarify. Thanks, -LN ------------------------------------------------------------------ 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