Ray, If you are trying to TDR traces which jump between layers and change impedance, you will run into the issue known as multiple reflections. If you would like to learn more, check out the appnote "TDR Primer," or "PCB Interconnect Characterization from TDR Measurements" on our web site, www.tdasystems.com/support You will also find a number of other appnotes there related to SI analysis of gigabit links using TDR and VNA. Thanks, =================== Dima Smolyansky TDA Systems, Inc. 4000 Kruse Way Place Bldg. 2, Suite 300 Lake Oswego, OR 97035 (503) 246-2272 (503) 246-2282 (fax) Download new IConnect 3.0 Quick Tour at www.tdasystems.com/products/ ! ----- Original Message ----- From: "Ray Haynes" <ray.haynes@xxxxxxxxxxxxxxxx> To: "SI List" <si-list@xxxxxxxxxxxxx> Sent: Tuesday, November 11, 2003 11:21 PM Subject: [SI-LIST] TDR Recommendations > Good day list members, > I need some guidance. We have just competed a design that uses 2Gb/s > proprietary communication channels to interconnect boards. I will be > getting the artwork on the first board back soon and I'm going to need > to do some SI work on it. These frequencies are a magnitude higher than > anything I have worked with before. We were very conservative on the > layout but I'm going to want to verify the artwork with a TDR scope. > > I'm thinking 20GHz bandwidth for the scope and a pulse rise time should > probably be better than 50ps. The signals are differential so I need > that capability in the TDR Head. Does this sound about right? > > If my assumptions are correct then are these likely candidates? > Tek 11800 series with SD24 TDR Sampling Head > Tek TDS8000 with 80E04 TDR Sampling Module > Agilent 54750 with 53754A TDR module > Agilent 86100 DCA w/ 53754A Differential TDR Module > > Am I in the ball park? > > Ray "Gigahertz Green" Haynes > Phoenix, AZ > > > ------------------------------------------------------------------ > 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.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 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