Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
(a,b) Isolation of first harmonic. The echolocation calls were broadband FM sweeps with a prominent second harmonic. The first harmonic was isolated by harmonic filtering, which removed the interference in time signals and spectra that was due to the frequency overlap between first and second harmonic.
