From WordNet (r) 3.0 (2006) :
amplitude modulation
n 1: modulation of the amplitude of the (radio) carrier wave
[syn: amplitude modulation, AM]
From The Free On-line Dictionary of Computing (30 December 2018) :
Amplitude Modulation
(AM) A method of encoding data by varying
the amplitude of a constant frequency carrier.
Contrast Frequency Modulation.
(2001-04-30)