> How do I specify an aribtrary ac source in gschem? For example, > I want a current a source of e^(At)sin(Bt) where A and B are some constants. > > I have tried searching google, but am not sure what I should > specifically search for. I have found that I can specify an ac source > with an amplitude and a phase, but not how to specify a source which an > arbitrary function of time.
Ummmm, what kind of arbitrary AC source are you looking for? I assume SPICE. If so, SPICE doesn't support arbitrary source waveforms using a single device. It gives you things like sine, PWL, DC, and a few others which I have forgotten. Here's the SPICE documentation on sources: http://newton.ex.ac.uk/teaching/CDHW/Electronics2/userguide/sec3.html#3.2 If you really need a decaying sine wave, you can create one using the nonlinear dependent source element B: http://newton.ex.ac.uk/teaching/CDHW/Electronics2/userguide/sec3.html#3.2.3 Instantiate a sine wave independent source, an exponential independent source, and then combine them together with a B source to create your decaying exponential. As for whether spice-sdb supports nonlinear dependent sources, I belive it doesn't [1]. :-( You'll need to edit the netlist by hand to get it in there. :-( :-( Alternately, you can make an independent source symbol, give it a DEVICE=NONLINEAR_INDEPENDENT_SOURCE and edit spice-sdb to spit out a SPICE B card when it finds an NONLINEAR_DEPENDENT_SOURCE. It's not difficult. If you do this, please submit the patches, and I'll integrate them into spice-sdb. Stuart [1] I forget everything which is in there. It wouldn't hurt to look for the symbol before you do anything else.
