Modes
A mode is the way of changing electromagnetic waves, modulating them so that transmission of information is possible. There are three "true" modes, or methods of modulation: Amplitude Modulation (AM), Frequency Modulation (FM) and Continuous Wave (CW)
"True" Modes
Digital modes
Technically, whenever a signal is turned on and off to enable transmission of information, it can be considered to be a digital mode. Under this definition, CW is certainly a digital mode. This section refers to methods of transmitting that are digital, or that require digital processing in part of the transmission or receiving process.