Figure 2.

Analysis and synthesis of the 40 kHz harmonic vocalization. A, Background noise and small recording artifacts are present in the original recording. B, Synthesis of the signal faithfully regenerated the harmonic content of the vocalization in the absence of the noise present in the original recording. C, Duration doubled without altering the frequency. D, AM removed without altering the FM. E, FM removed without altering the AM. F, An inharmonic vocalization generated by multiplying the fundamental frequency by 150%.