Hi Stephen thank you for trying it at your end, but the put what I am looking is not correct. I hope you should be seeing a output like one what I have attached. But it should be like the one shown in the next picture. The red colored line is the one measured with this touchstone, but in a different tool. please let me know what should i chnage in the netlist. Mani On Fri, Aug 6, 2010 at 8:06 AM, Stephen Zinck <szinck1@xxxxxxxxxxxx> wrote: > Hi Mani, > > This differential TDR netlist worked fine for me. I don't see any > problems... > > Best regards, > Steve > > Stephen P. Zinck > High-Speed Signal Integrity Consulting > Interconnect Engineering Inc. > P.O. Box 577 > South Berwick, ME 03908 > Phone - (207) 384-8280 > Email - szinck@xxxxxxxxxxxxxxxxxxxxxxxxxxx > Web - www.interconnectengineering.com > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] > On > Behalf Of Mani Ganesan > Sent: Thursday, August 05, 2010 07:04 PM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] TDR in HSPICE from S parameter Touchstone File > > Hi All > I have a small problem in doing TDR in HSPICE. I simulated my high speed > trace in HFSS and got the s parameter touchstone file from DC to 20GHz > incrementing at 10MHz. > > I am trying to do TDR anlysis in HSPICE and would like to plot it. > > Can anyone confirm my following netlist and please let me know my mistakes > as the impdeance TDR output is not correct? Please see the attached TDR > output. > > Please let me know where I am going wrong. > > .opt post probe runlvl=5 > .tran 0.005n 8n > S1 inp inn outp outn 0 mname=s_model > .model s_model S N=4 TSTONEFILE="touchstone_name.s4p" > + fbase=1e7 > + fmax=20e9 > > .param vinput = 1.0 > .param zref = 50.0 > > P1 inp_ inn_ 0 zo=zref port=1 pulse(0v vinput 1ns 0.01ns 0.01ns) > > TdrP inp_ 0 inp 0 Zo=zref td=1n > TdrN inn_ 0 inn 0 Zo=zref td=1n > > P2 outp outn 0 zo=zref port=2 > > Pref refp refn 0 zo=zref port=3 pulse(0v vinput 1ns 0.01ns 0.01ns) > PrefT refp refn 0 zo=zref port=4 > > .probe tran V(inp) V(inn) V(outp) V(outn) > .probe tran vincident = par('v(refp)-v(refn)') > .probe tran vdiff = par('v(inp_)-v(inn_)') > .probe tran vreflect = par('vdiff-vincident') > .probe tran TDRdiff = par('2*zref*(vincident + vreflect)/(vincident - > vreflect)') > > .end > > Thank You > Mani > > > > ------------------------------------------------------------------ > 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 > > 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 technical documents are available at: http://www.si-list.net 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