In music, the term "modulation" means a key change. This article is about the concept of signal modulation in communications engineering.
Modulation describes a range of techniques for encoding information on a carrier signal, typically a sine-wave signal. A device that performs modulation is known as a modulator.
Modulation techniques include:
Pulse modulation techniques include:
Where Morse code is used to turn the carrier wave on and off, the term used is not 'amplitude keying', but 'continuous wave' (CW) operation.
Modulation is frequently used in conjunction with various channel access methods.