Convergence problems with functions and sampled signals

[xyz123]

Hello all,

I have attached a sheet with a simple example function where the voltage jumps. This causes convergence problems. 

I am working actually more complex signal at a capacitor, but I cant share my actual sheet.

Basically my attached example is the same... I have waveform with a discontinuity.

Later I do a derivation of the voltage signal.

Also I want to do a FFT of this signal and therefore I sample it.

In any way I have convergence problems and I dont know how to handle that. Do you have an idea?

Here is a screenshot of the sheet in case you cannot open it:

[xyz123]

I changed to voltage function in the new sheet, have a look. This is more realistical to my actual convergence problem than the previous sheet. 

[Werner_E]

How about defining Icap(t) using a "try ... on error ...." construct.?
The "try" case would contain the original definition of Icap and the "on error" case a meaningful value or rather a NaN.

[ttokoro · Accepted solution]

Use sampling data you can get what you want. Prime 8 sheet attached.

If you want its Fourier series, my answer bellow shows how to do it.

Fourier Puzzle - PTC Community