I post below two fourier graphs of the same signal, simulated for two different transient durations:
The time domain function is a sine with 60Hz frequency.
- Transient duration 40ms gives the following fourier graph:
- Transient duration of 300ms gives the following Fourier graph:
I had expected the fundamental frequency used to calculate the coefficients to be 60Hz, the main frequency of the time domain function.
But the simulator uses the transient duration as a period to compute first the fundamental frequency and then calculates the Fourier coefficient.
Is that convenient event though the sine function is periodic?
In the simulator window, there is something called Resolution/Frequency; what is the link between this resolution and the formula used to calculate the coefficients of a Fourier series?
NB: the simulator is Simplis/Simetrix for power electronics.