I haven't matched the audio up with the file, but I don't think its necessary for the example attached. The gist is that I am using the 1st, 2nd and 3rd derivative to look at a fish vocalization. the 3-D plot on the left shows those data points (based on what I read in the manual). I took a min-max of each series as well and plotted on the right in the stem for each snapshot (its slowed down by about a factor of 10, the signal is about 2.5 seconds long. I think I am looking at a periodic non-linear signal (this makes sense since the fish is basically vocalizing with a set of sin waves so I expect continuous derivatives).

in summary, since each derivative is uniform but mean power is ~=0, the signal is non-linear periodic. if I'm wrong, can you please tell me where?