Sorry for previous mail, it got avay too early. Al Davis: > On Sunday 07 April 2013, Karl Hammar wrote: > > I get different volt calculated vs. measured in node 2 of > > simulation below. Can anyone point to where my mistake is? > > > > It should be 0.5 V for 50 Ohm input impedance but only > > measures to less than 200 mV. Replacing circuit 50 Ohm BNC > > terminator gives me the correct 500mV. > > > > My stuff is available in: > > > > http://turkos.aspodata.se/git/openhw/rfid/ ... > My guess at where the mistake is .. something you haven't shown > us.
Yes, isn't that the way it usually is. I have a function generator, koax to scope, bnc-t to anenna pcb, and I get better values now. So Im' kindof satisfied, but still have to learn gnucap better. ... > Gnucap 2009.12.07 RCS 26.136 We seems to have differnt versions, I'll try to get the same as yours. > ..... > gnucap> spice > gnucap-spice>C1a 2 4 7.39e-10 > gnucap-spice>C1b 0 3 7.39e-10 > gnucap-spice>C2 2 0 1.65e-09 > gnucap-spice>Cpar 4 3 1e-11 > gnucap-spice>L 4 3 4.4e-07 > gnucap-spice>Rpar 4 3 1500 > gnucap-spice>.print ac z(2) zp(2) zr(2) zi(2) > gnucap-spice>.ac 12meg 14meg 10k > #Freq z(2) zp(2) zr(2) zi(2) ... > 12.33Meg 0.82071 -1.8369 0.82028 -0.026307 > 12.34Meg 0.83455 2.1224 0.83398 0.030907 ... > 13.6Meg 50.85 -11.238 49.875 -9.9101 > 13.61Meg 50.855 -14.512 49.233 -12.743 > 13.62Meg 50.694 -17.73 48.286 -15.438 ... Good point. How did you manage to get the value 50, should one not include the signal source or can one leave that out? ... > It's interesting that zero-phase occurs at a different frequency > than max voltage or max impedance. Probably because the sought resonance is over the inductor and at the connector we see a C2 paralell with 2*C1a + L//Rpar. > Your use of the "generator" keyword is probably not what you > want, but that is not the problem here. Since you specified an > AC value, it overrides the "generator" making it apply only to > transient analysis. Sorry, but I'm new to gnucap. I got that when I run gnetlist -g spice test.sch I have since deleted that file and it's output since it did not have a node 0 and gave strange results when running the simulation. Regards, /Karl Hammar ----------------------------------------------------------------------- Aspö Data Lilla Aspö 148 S-742 94 Östhammar Sweden +46 173 140 57 _______________________________________________ Help-gnucap mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-gnucap
