My understanding is that you are calibrating to the 3.5mm connector using t= he 85052D cal kit, then trying to measure something at the end of an adapter a= nd length of cable. If this is the case, then I'm not surprised you see some ripple (or "noise"). The ripple is likely due to the adapter and length of cable. You would need to deembed this using a model of the probe or some so= rt of deembedding algorithm using reflects at the end of the probe. At a minimum, the electrical delay from the calibration plane to the end of the probe should be calculated or measured and removed from the measurement. -- Daniel > ----- Original Message ----- > From: "travis ellis" <travissellis@xxxxxxxxx> > To: "Hill, John" <jhill@xxxxxxxxxx>, si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Re: S-parameter passivity... Interpreting the results. > Date: Tue, 13 Jun 2006 09:19:29 -0700 (PDT) >=20 >=20 > I'm using the 8052D broadband economy calibration kit. I've performed a = full 2port SOLT=20 > calibration calibrating out the cabling. All of which use 3.5mm connecto= rs. Then I attach port=20 > 2 to a 3.5mm - GPPO connector that attaches to a 0.085 gppo terminated c= able on one end. The=20 > other end of the cable (DUT) has a coaxial probe. Port 1 is attached to = an sma to gpo=20 > connector that is mounted in a brass block and ground smooth. This provi= des a coaxial structure=20 > that I make contact to with the coaxial probe that is on the other end o= f the dut. >=20 > Travis > "Hill, John" <jhill@xxxxxxxxxx> wrote: Travis, >=20 > Which Calibration kit are you using and can you describe what is between > the calibration plane and the thing you are trying to model? BTW, what > RF connector are you using? >=20 > Best regards, >=20 > John >=20 >=20 >=20 >=20 > --------------------------------------- > The information in this email and attachments hereto may contain legally= privileged,=20 > proprietary or confidential information that is intended for a particula= r recipient. If you are=20 > not the intended recipient(s), or the employee or agent responsible for = delivery of this=20 > message to the intended recipient(s), you are hereby notified that any d= isclosure, copying,=20 > distribution, retention or use of the contents of this e-mail informatio= n is prohibited and may=20 > be unlawful. When addressed to Takata customers or vendors, any informat= ion contained in this=20 > e-mail is subject to the terms and conditions in the governing contract,= if applicable. If you=20 > have received this communication in error, please immediately notify us = by return e-mail,=20 > permanently delete any electronic copies of this communication and destr= oy any paper copies. > --------------------------------------- > -----Original Message----- >=20 > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] > On Behalf Of travis ellis > Sent: Tuesday, June 13, 2006 11:00 AM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] S-parameter passivity... Interpreting the results. >=20 > I've been taking measurements with a VNA then running them through a > passivity checker. The basis for the code was originally posted by Ray. > I've modified it to meet my needs. Added plotting capabilities, log mag > format handling, and nudging of the non-passive values when only a few > points are out of spec etc. I don't think I broke anything in the > process but what I've noticed is that the eigen values of some of my > measurements are very noisy. The better measurements oscillate too but > they trend upward with increasing frequency. The suspect measurements > oscillate between near 0 and approximately 0.4 from point to point > across the higher frequency bands. The magnitude of the s-parameters > seem to be noisy as well. I've gone through my setup to make sure that > my cables don't have loose/bad connections. Replaced some connectors > that seemed inadequate and while things got marginally better the > measurements still contained noise. The noise source seems to be my > fixturing. Unfortunately I don't think I can improve this given my time > constraints. >=20 > The only thing that I've noticed is that the time domain simulations > take longer than those created with a data set that isn't as noisy. >=20 >=20 > Is there a way to decide if these models are accurate enough to be > reliable? >=20 > Regards, >=20 > Travis --=20 ___________________________________________________ Play 100s of games for FREE! http://games.mail.com/ ------------------------------------------------------------------ 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: http://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: http://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