Christoph,
For time-domain and frequency-domain plots, I think LTspice only connects the dots with lines or curves.? I think there is no other option.
I have seen .STEPped simulations where LTspice's plot window showed vertical lines, but this was actually annoying because it did not plot what I actually wanted to see.? So I have forgotten now how that happened.? I did not see it as something useful, at the time.??Anyway, I do not believe there is any option to make it do that, at least not when plotting waveforms vs. time.
I agree with John that you probably need to turn to another plotting program (e.g., Excel).
Also, FYI, even if your PWL data has discrete time points, it is likely that LTspice simulated between those time points.? Even if you could make LTspice (or Excel) plot only the simulated time points as dots or vertical lines, there would likely be values at times between the points of your PWL data.? This is just how SPICE has to work.? There are times when it needs to simulate between the raw data.? That cannot be changed.
So, if you used Excel, you could also filter out those time values that don't correspond to your PWL file's raw data.
Andy
