Hermann, frequency dependent loss in the signal band will give you pattern dependent distortion, IE DCD. Steve Hermann Ruckerbauer wrote: > Hello, > > I'm just looking in PCI express gen2 simulations, but do not fully > understand the Spec regarding DCD and Jitter (low and high frequency) > for worst case simulations. > > There is mentioned, that the simulation should be done with 0.1 DCD. > Additionally there are 78ps Dj and 28ps for slewing the eye. > > 0.15UI is the max. High Frequency TX jitter. From this 30ps (0.15UI) > one should include 0.1UI (20ps) as DCD in the simulation. > ==> What is the Jitter distribution, that should be assumed here? > I guess a fixed 0.1UI DCD is not correct. Personally I would use +- > 0.05UI with some gaussian distribution, but I'm not sure if this is the > intension there. > This would reduce the eye size, but still results in a nice symmetric eye. > So in my understanding this is not really a Duty cylce distortion with > e.g. each even bit short and each odd bit long, but high frequency > jitter e. g. introduced by SSO noise and package x-talk. > ==> Is my understanding correct ? > > Additionally there is a value of 78ps Dj mentioned. not sure if I need > to add this in simulation or data evaluation, or if this is accounted > for by the DCD already. > ==> My understanding is, that this is the max value of the sum of the > 0.1DCD + the Jitter introduced by the channel. > Is this correct, or do I need to add this DJ in addition (in simulation > or data evaluation)? > I can evaluate this, but if I place a Receiver eye mask it should be > enough not to violate the mask, correct ? > > > Finally there is there is the jitter that I need to add in the > dataevaluation by slewing the eye (e. g. 28.9ps for common clock > architecture. > ==> is it OK to expand the eye mask by this number (+-15ps from the > center) ? > > So far i have not seen any documents that describe it in a way that I > would understand it (guess I'm just to stupid). Maybe somebody can > enlighten me here, or point me to some description. > > Thanks and regards > > Hermann > > > > > EKH - EyeKnowHow > Hermann Ruckerbauer > www.eyeknowhow.de > hermann.ruckerbauer@xxxxxxxxxxxxx > Veilchenstrasse 1 > 94554 Moos > Tel.: +49 (0)9938 / 902 083 > Mobile: +49 (0)176 / 787 787 77 > Fax: +49 (0)3212 / 121 9008 > > > ------------------------------------------------------------------ > 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 > > > > -- Steve Weir IPBLOX, LLC 150 N. Center St. #211 Reno, NV 89501 (866) 675-4630 Business (707) 780-1951 Fax http://www.ipblox.com A Teraspeed Consulting Group LLC Partner Teraspeed Consulting Group 121 North River Drive Narragansett, RI 02882 (401) 284-1827 Business (401) 284-1840 Fax Teraspeed Labs 13610 SW Harness Lane Beaverton, OR 97008 (503) 430-1065 Business (503) 430-1285 Fax A Teraspeed Consulting Group LLC Partner http://www.teraspeed.com This e-mail contains proprietary and confidential intellectual property of IPBLOX LLC ------------------------------------------------------------------------------------------------------ Teraspeed(R) is the registered service mark of Teraspeed Consulting Group LLC ------------------------------------------------------------------ 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