Guilin Sun
Ansys Employee

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. 

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