Dear steve Could you give me the list of the papers? Best Regards Zhangkun 2004.5.18 ----- Original Message ----- From: "steve weir" <weirsp@xxxxxxxxxx> To: <istvan.novak@xxxxxxxxxxxxxxxx>; <zhang_kun@xxxxxxxxxx>; "si-list" <si-list@xxxxxxxxxxxxx> Sent: Tuesday, May 18, 2004 9:38 PM Subject: Re: [SI-LIST] Re: Fw: Re: The Ground of VNA > Istvan, Zhnagkun, in addition to a balun from MiniCircuits, to avoid stray > coupling effects, a good chunk of common mode ferrite can be helpful. Doug > Smith has written quite a bit about stray coupling messing up measurements, > how to detect it is happening, and how to fix it. > > Regards, > > > Steve. > At 09:02 AM 5/18/2004 -0400, Istvan NOVAK wrote: > >Dear Zhangkun, > > > >OK; not having a ground plane for differential pairs clearly > >falls into the category when the ground loop of the VNA will > >influence your result over a wide band. > > > >You could try balun transformers to transform the > >differential connections to single ended. MiniCircuits > >has a wide range of transformers for all frequency > >ranges. > > > >Best regards, > > > >Istvan > > > > > >----- Original Message ----- > >From: "Zhangkun" <zhang_kun@xxxxxxxxxx> > >To: "si-list" <si-list@xxxxxxxxxxxxx> > >Sent: Tuesday, May 18, 2004 8:00 AM > >Subject: [SI-LIST] Fw: Re: The Ground of VNA > > > > > > > > > > ----- Original Message ----- > > > From: "Zhangkun" <zhang_kun@xxxxxxxxxx> > > > To: <istvan.novak@xxxxxxxxxxxxxxxx> > > > Sent: Tuesday, May 18, 2004 7:52 PM > > > Subject: Re: [SI-LIST] Re: The Ground of VNA > > > > > > > > > > Dear Istvan > > > > > > > > The following is my understand about the ground loop in VNA. > > > > > > > > When measurement is done by means of VNA, there is two impedance between > >the ground of two ports: > > > > 1. In the VNA, because the instrument is single-ended connections, > >there is finite impedance (Calling Za)between the two ground. > > > > 2. In the DUT, there is impedance unknow (Calling Zb). > > > > Za and Zb are in parallel. > > > > > > > > When Za<Zb, Za is dominant. The measurement result will be influnced by > >the ground loop. For example, there are two differential pair with no ground > >plane. The crosstalk should be measured. Therefore, the ground loop should > >be butted by transformer of 1:1. > > > > When Za>Zb, Zb is dominant. The measurement result will not be influnced > >by the ground loop. For example, in the DUT, there is complete reference > >plane. > > > > > > > > I have found that in different situation, the effect of ground loop in > >VNA is different. In current measurement about crosstalk between > >differential pairs with no reference plane, the influnce could get to above > >20MHz. Now my difficulty is that I could not found one suit transformer of > >1:1 to break the ground loop. > > > > > > > > Best Regards > > > > > > > > Zhangkun > > > > 2004.5.18 > > > > ----- Original Message ----- > > > > From: "Istvan NOVAK" <istvan.novak@xxxxxxxxxxxxxxxx> > > > > To: <zhang_kun@xxxxxxxxxx>; "si-list" <si-list@xxxxxxxxxxxxx> > > > > Sent: Tuesday, May 18, 2004 7:18 PM > > > > Subject: [SI-LIST] Re: The Ground of VNA > > > > > > > > > > > > > Dear Zhangkun, > > > > > > > > > > High-frequency instruments use single-ended connections; > > > > > most of the differential inputs and outputs are also formed > > > > > of individual single-ended connections. When you make > > > > > the connection from a VNA to the DUT with two cables, > > > > > you make a ground loop. The ground loop creates a > > > > > problem only at low frequencies, where the resistance of > > > > > the cable braid dominates the return-path impedance. > > > > > At high frequencies (with most cables above a few MHz), > > > > > the inductance of the cable braid opens the ground loop > > > > > so much so that you can cross-connect the cables by > > > > > connecting the hot side of cable1 to the ground side of > > > > > cable2 and hot side of cable2 to the ground side of cable1 > > > > > and under some circumstances you will hardly notice the > > > > > difference in the response. > > > > > > > > > > Regards, > > > > > > > > > > Istvan Novak > > > > > SUN Microsystems > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > From: "Zhangkun" <zhang_kun@xxxxxxxxxx> > > > > > To: "si-list" <si-list@xxxxxxxxxxxxx> > > > > > Sent: Tuesday, May 18, 2004 5:12 AM > > > > > Subject: [SI-LIST] The Ground of VNA > > > > > > > > > > > > > > > > Dear All > > > > > > Could you tell me the details about the ground of VNA? From the > > > > > experiment, I could find out that the ground of two ports of VNA are > > > > > connected. However, I do not know the detail. > > > > > > > > > > > > This is critical for some kind of analysis. For example, there is no > > > > > ground plane. > > > > > > > > > > > > Best Regards > > > > > > > > > > > > Zhangkun > > > > > > 2004.5.18 > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------ > > > > > > 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 > > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------ > > > > > 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 > > > > > > > > > > > > > > > > > ------------------------------------------------------------------ > > > 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 > > > > > > > > > >------------------------------------------------------------------ > >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 > > > > ------------------------------------------------------------------ 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