Dear Lim, The quiet line is a traditional way to quantify the crosstalk in mV on a signal (called the victim) caused by one or more sources (called aggressors) switching nearby. If you have good control over the patterns you send across a bus, you can probe the quiet line noise by causing only the aggressors to switch in the same direction at the same time while sending a long string of zeros or ones on every other bit. It used to be we were interested in making sure that crosstalk didn't get large enough to switch a bit that was supposed to be static - hence the name quiet line noise. On multi-gigabit interfaces we are more interested in knowing how much crosstalk causes the victim eye pattern to close in ps and in mV, but the quiet line remains a good way to quantify how strong the crosstalk is. Of course, you can do this experiment in simulation, too. If you do the same experiment allowing all bits to switch in the same direction at the same time EXCEPT the victim, you will be measuring the effects of crosstalk AND voltage disturbance on the power distribution system caused by so many drivers all demanding electrons at the same time. Greg Edlund Senior Engineer Signal Integrity IBM Engineering and Technology Services 3605 Hwy. 52 N, Dept. HDC Rochester, MN 55901 gedlund@xxxxxxxxxx Msg: #2 in digest Date: Tue, 18 Jan 2005 23:48:24 +0000 (GMT) From: =?euc-kr?B?wNO1v7z4?= <dongsoon72.lim@xxxxxxxxxxx> Subject: [SI-LIST] what is quiet line noise Hi Experts/ Anyone know of Quiet line noise ? Thanks in advance Regards, Lim ------------------------------------------------------------------ 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