0.35/Tr ---- 10% to 90% 0.22/Tr ---- 20% to 80% Regards, Cortex ________________________________ From: si-list-bounce@xxxxxxxxxxxxx ¥N²z Tom Dagostino Sent: 2006/1/6 [¬P´Á¤] ¤W¤È 10:03 To: rula.bakleh@xxxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Maximum frequency consideration for high-speed digital analysis of differential signals I'm not sure how you are computing your bandwidth. If you have a 25 psec risetime (assuming 10-90%) your -3dB bandwidth is 0.35/25psec or 14 GHz. When analyzing bandwidth requirements for systems like this most people talk about passing the 3rd or 5th harmonic of the clock. In your case that is 7.5 or 12.5 GHz. Some analysis of your system requirements is in order. Tom Dagostino Teraspeed(R) Labs 13610 SW Harness Lane Beaverton, OR 97008 503-430-1065 tom@xxxxxxxxxxxxx www.teraspeed.com Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 401-284-1827 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of rula.bakleh@xxxxxxxxxx Sent: Thursday, January 05, 2006 2:19 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Maximum frequency consideration for high-speed digital analysis of differential signals Hi Everyone, I'm designing a differential signal for the Rocket I/O interface. My signal speed is 5 Gbit/sec, operating frequency is 2.5 GHz, and fastest edge rate is 25 psec or 40 GHz. In regards to performing channel analysis, what is the highest frequency content to consider when designing this particular differential signal serial link? If I am measuring or simulating S parameters for various portions of this link what is the highest frequency of interest that I need to consider as a rule of thumb and why? Is it the operating frequency only, multiples/harmonics of the operating freq, edge rate frequency (f=1/trise), multiples/harmonics of the edge rate freq, or some fraction of the edge rate? I'm finding conflicting information: some people say that it's the full edge rate, others say 0.35 or 0.5 of the edge rate, and yet others say multiples of the edge frequency should be taken into account for analysis and design. I'm hoping that somebody could shed some light on this topic for me. Thank You, Rula Bakleh ------------------------------------------------------------------ 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 ------------------------------------------------------------------ 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