Editing Amplitude modulation (section)

=== Shift keying ===
A simple form of digital amplitude modulation which can be used for transmitting [[digital data|binary data]] is [[on–off keying]], the simplest form of amplitude-shift keying, in which [[binary numeral system|ones and zeros]] are represented by the presence or absence of a carrier. On–off keying is likewise used by radio amateurs to transmit [[Morse code]] where it is known as continuous wave (CW) operation, even though the transmission is not strictly "continuous". A more complex form of AM, [[quadrature amplitude modulation]] is now more commonly used with digital data, while making more efficient use of the available bandwidth.