A signal and the magnitude of its analytic signal, to demonstrate the envelope effect. I made it using Octave (that uses Gnuplot internally to output in SVG).
original work by <a href="//commons.wikimedia.org/wiki/User:Omegatron" title="User:Omegatron">User:Omegatron</a>, adapted to SVG by <a href="//commons.wikimedia.org/wiki/User:Alejo2083" title="User:Alejo2083">Alessio Damato</a>
CC BY-SA 3.0
<a href="//commons.wikimedia.org/wiki/File:Analytic.png" title="File:Analytic.png">Image:Analytic.png</a>