The emission designator begins with the necessary bandwidth, followed by three symbols. The first symbol identifies the type of modulation of the main carrier. The second identifies the nature of the signal or signals modulating the carrier. The third identifies the type of information transmitted.
| Position | What it describes | Examples / notes |
|---|---|---|
| Bandwidth | Necessary bandwidth | Written before the three symbols, for example 2K80. |
| First symbol | Modulation of main carrier | A: double-sideband AM; J: SSB suppressed carrier; F: frequency modulation. |
| Second symbol | Nature of modulating signal | Single or multiple channels; digital or analogue characteristics. |
| Third symbol | Type of information | Telegraphy, telephony, facsimile, television, data or combinations. |
The complete ITU emission table contains more symbols and detailed definitions. Use the current ITU Radio Regulations, Appendix 1, when interpreting a designator for legal or engineering work.