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.
Top panel: An Instrinsic Mode function from a simulated signal (black line) and an amplitude threshold (dotted line). Bottom Panel: 2D Hilbert-Huang Transform. Darker colours indicate greater power and the black lines indicate cycle average instantaneous frequency of large amplitude cycles.
