> In each chirp, there is one fundamental frequency at about 100 kHz, then another one at about 50 kHz, and two more above it at 150 kHz and 182 kHz.
Or a 50kHz fundamental frequency with overtones at 100, 150 and 200 (which looks like 384-200=184 because of aliasing, notice how the shape is reflected).
Or a 50kHz fundamental frequency with overtones at 100, 150 and 200 (which looks like 384-200=184 because of aliasing, notice how the shape is reflected).