Hi all,
I am trying to get the DFT of the output waveform to get SINAD and ENOB. There are some things I am not sure about when reading at the help section about spectrum:
At a certain point it says: "The Sample Count value must be greater than zero. By default, this field displays the number of data points in the selected signal." but if I am looking at a waveform that lasts 20.48 us and time step during simulation was 1 ns means that the trace has 20480 points, but by default I get 1024 in the Sample Count field, why is that?
At another point it says: "The number of input periods in the period of the Fourier transform needs to be an integer and a prime number, where the period of the Fourier transform is 1/ the fundamental frequency of the Fourier transform." So it is saying that the interval stop time-start time should be an integer number of periods of my waveform, and that is ok, but why should it also be a prime number?
Also I am not sure about how the signal first harmonic is chosen, is it just the one with bigger amplitude?
Thanks a lot for your help