Hi Mario, Both types of injection are possible. You could also have an antenna effect which is a little different because the effective source impedance is different from both pure current injection and pure voltage injection. Your method is correct for capacitive coupling (often called E-field coupling). For Inductive (or B-field coupling), you should use a transformer with the primary attached to a pulsed current source and the secondary in series with your signal. You probably want to short either the primary or secondary with a resistor, too, since the transformer will not truly have ideal transformer behavior. Ultimately, though, all of these phenomena have the same effect - causing noise in your signal. If you want to model how noise affects your circuit, you can do it by simply adding a voltage source in series or a current source in parallel with your signal. If you are trying to model how MUCH noise you get from some particular external influence, that is much more difficult and will depend on the details of the external source. For example, I once had to model crosstalk between two long traces which ran parallel to each other on a PCB. I used LTSpice's built-in coupled transmission line model for this but I had to look up how to convert the circuit physical dimensions to the transmission line parameters by looking at microstrip transmission line models. Sean On Thu, Dec 15, 2011 at 9:26 AM, Electron wrote: > > Hello, > how can I model EMI (for use in LT-Spice IV)? > > Say I have a pulsed voltage source with a certain source impedance, my si= gnal, how can/should > I add simulated EMI? What is injected, current or voltage? > > I thought about using another pulsed voltage source of higher impedance, = capacitively coupled > to my original one. > > Is it the right way? > > Thanks! > > With kind regards, > Mario > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .