Mick, The statements your colleagues made are in general true about printed circuit board striplines. They are not true about microstrips. They are not necessarily true about connectors. Depending on the design of the connector, the electric and magnetic fields may not be well-balanced, leading to nonzero forward crosstalk. The big difference between striplines and connectors is that the transverse electromagnetic mode is present in the stripline but typically breaks down when it encounters the connector. In the transverse electromagnetic mode, the electric and magnetic field vectors are perpendicular to each other and to the direction of propagation. When the TEM wave moves into the connector, the electric and magnetic field lines are not necessarily perpendicular to each other anymore, although each one by itself is still perpendicular to the direction of propagation. Greg Greg Edlund Senior Engineer Signal Integrity and System Timing IBM Corporation 3605 Hwy. 52 N Bldg 050-2 Rochester, MN 55901 Msg: #6 in digest Date: Mon, 23 Feb 2009 16:58:47 -0700 Subject: [SI-LIST] general belief about Xtalk From: Mick zhou <mick.zhou@xxxxxxxxx> Hi, Recently, I run into some basic beliefs about Xtalk from my colleagues. They seem match intuiations but may not be right. Statement 1: Single-ended near-end Xtalk is always greater than far-end Xtalk, both in f and t domains. Statement 2: Differential/Common near-end Xtalk is always greater than the far-end, both in f and t domains. I do not remember any general proofs of the above statements. They may be true for many practical cases but may not be generally true. One example in S. H. Hall's book, p.50. disproves the statement 1 in t-domain. Any more helps? Mick ------------------------------------------------------------------ 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