Modulation classification

This page contains an abstract of the modulation classification according to the ITU standard.

The classification is done with a three-symbol code: the first symbol (which is usually a letter) describes the modulation of the main carrier, the second symbol (which is usually a digit) describes the signal that modulates the main carrier and the third symbol (which is usually a letter) describes the transmitted information.

Extra modulations only used for a short amount of time (for example for sending the call-ID) are often not taken into account if the main bandwidth is not increased.

First symbol: modulation of the main carrier	Second symbol: type of signal(s) modulating the main carrier	Third symbol: type of transmitted information
N Unmodulated carrier Amplitude modulation A Double sideband amplitude modulated carrier. H Single sideband, full carrier R Single sideband, reduced (or variable) carrier. J Single sideband, suppressed carrier B Independent sidebands C Vestigial sideband Angular modulation F Frequency modulation G Phase modulation Pulse modulation D Amplitude and phase modulation P Unmodulated pulse modulation K Pulse amplitude modulation L Pulse width/length modulation M Pulse position/phase modulation Q Phase modulation during pulses V Other pulse modulations Other modulations W Other combinations of amplitude, phase and pulse modulation X Other modulations	0 No modulation signal 1 One digital channel, no subcarrier 2 One digital channel, with subcarrier 3 One analog channel 7 Two or more digital channels 8 Two or more analog channels 9 Compound system with one or more digital channels and one or more analog channels X Other signals	N No information A Telegraph - manual decoding B Telegraph - automatic decoding C Fax D Data transmission, remote control E Telephone, audio F Television, video W Combination of the above X Other information

Examples: