You searched for: “amplitude modulations
amplitude modulation, AM (s) (noun), amplitude modulations (pl)
The deliberate processing of a carrier signal which is used in ordinary radio and TV broadcasting: The amplitude modulation varies in accordance with the level of the modulating signal while transmitting the video portion of a television signal.

Variation of the amplitude modulation of a carrier wave, commonly a radio wave, presents fluctuations in the audio or video signals that are being transmitted.

A higher amplitude modulation wave is interpreted as a "1" and a normal wave is interpreted as a zero.

The method of changing an amplitude modulation is known as "amplitude shift keying", or ASK.