Hi Jennifer, I'm wondering if you'd tried ADS Transient Convolution simulator? Our Broadband SPICE Model Generator uses a rational function approach: B. Gustavsen and A. Semlyen, "Rational approximation of frequency domain responses by vector fitting," IEEE Trans. Power Delivery, Vol. 14, No. 3, pp. 1052-1061, July 1999. ...which can yield an excellent model in certain circumstance. However, ADS Transient Convolution has a more general approach: http://cp.literature.agilent.com/litweb/pdf/5990-3571EN.pdf I was wondering if you'd had the opportunity to evaluate it? Best regards, -- Colin -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Jennifer Maharani Sent: Thursday, May 14, 2009 5:02 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Causality Many thanks Gary. I have used the broadband spice generator from Agilent. It does not fix the causality problem. On May 14, 2009, at 10:52 PM, "Gary Otonari" <garyo@xxxxxxxxxxxx> wrote: > Jennifer -- Do you have ADS? It might help you. Here is some > material on > recent advances in their transient simulator. The 1st link is for a > paper > we (GigaTest) did for the SI Seminar Series last year. The 2nd is a > webinar > on the same topic ( I think delivered by Sanjeev Gupta of Agilent). > Good > luck. > > -- Gary Otonari > > http://www.home.agilent.com/upload/cmc_upload/All/Meas_Based_Transient_Simul > ation_Gigatest.pdf > > http://www.home.agilent.com/agilent/editorial.jspx?cc=US&lc=eng&ckey=1454262 > &nid=-34511.0.00&id=1454262 > > > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx > ] On > Behalf Of Jennifer Maharani > Sent: Thursday, May 14, 2009 12:49 PM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Causality > > Dear all, > > I have non-passive non-causal S-parameter. I can use some commercial > tools that can generate broadband spice with passivity enforcement. > Not with causality enforcement, though. > > In transient simulation it clearly shows non-causal response. > > Does anybody know how to resolve this issue? Quick and dirty solution > will also be appreciated. > > Many thanks. ------------------------------------------------------------------ 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