Amplitude modulation

From Glossary of Meteorology

amplitude modulation

Changing the amplitude of a carrier wave by some means so that the resultant waveform transmits a signal conveying information.

For example, if the carrier wave with angular frequency ω is cos(ωt), the corresponding amplitude-modulated signal is
where g(t) is a function that varies more slowly with time than does the carrier wave.
Compare frequency modulation.