I guess the way to understand the mixed mode matrix (DD/CD/DC/CC) is to see how it is derived. From the single ended traveling/reflected (a/b) waves you can form the differential and common mode quantities of interest and then eliminate the unknowns using the single ended wave definitions. With that you will see how the mixed mode a/b waves relate to the single ended a/b quantities. You can find the derivations on line; Let me know if you can't find them..... Regards Antonis. -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of JS Sent: Wednesday, November 06, 2013 9:56 PM To: mark.marlett@xxxxxxxxx Cc: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Differential balanced measurements. Hi Thanks for input mark. This is because the two single-ended signals are out-of-phase when forming a differential signal it seems to me. All balanced measurements can be computed from single-ended measurements. So, 'SDD21' is really just a composition of single-ended S-parameters. On Wednesday, November 6, 2013 12:21 PM, Mark Marlett <mark.marlett@xxxxxxxxx> wrote: JS, I assume you are asking for an intuitive understanding and not a mathematically rigorous one. If so the answer is: SDD is the differential signal with no other content S21 and S43 contains differential + effects from other nodes say do to common mode signalling--- Since only one port is being stimulated wrt to the others. S23 and S41 contain the other effects. So to get purely differential signalling the other effects need to be subtracted off. Obviously the rigorous analysis also bears this out. Best Regards, Mark On Wed, Nov 6, 2013 at 9:01 AM, JS <jsven007@xxxxxxxxx> wrote: > Hi, Could someone help me, since I know there are a lot of SI experts. > Could someone confirm why in the differential calculation: > SDD21 = 1/2 (S21 - S41 - S23 + S43) The crosstalk terms of S23 and S41 > are subtracted from the loss terms (S21 and S43)? For example, for each > conductor of the differential pair the above equation becomes: > Conductor 1 S21 (thru loss) – S23 (crosstalk) > Conductor 2 S43 (thru loss) – S41 (crosstalk) > ------------------------------------------------------------------ > 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 forum is accessible at: > http://tech.groups.yahoo.com/group/si-list > > List archives are viewable at: > //www.freelists.org/archives/si-list > > 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu