Reply To: How to select the simulation time to accurately calculate the Q factor.

[Guilin Sun]

I am not sure what is the relation between Q and time. Since the signal is bounced back and forth, and using resonancefind is to get the Q from the signal analytically, it might be time dependent. For the signal like what you gave above, I would prefer to use fft method at the later 1/3 section. 

Actually the signal is not flat. instead, it is sinusoidal. Please zoom in and check, which should be the resonate frequency oscillating.