Amateur Emission Designations
Classification of Emissions.
Emission classifications provide an internationally recognised standard in which to specify accurately and concisely, the significant characteristics of a transmission.
A total of nine letters & figures are used. The first four give details of the bandwidth needed, the next three are the basic characteristics of the emission and the last two (optional) give any extra details which might be needed to further describe the emission.
6M25 C3F MN
6.25 MHz bandwidth vestigial sideband single channel analogue television monochrome signal with no multiplexing.
Following is a listing of emission types that maybe found in Amateur Radio
First Four Symbols
These give details of the bandwidth using three digits & one letter, with the letter providing the position of the decimal point. The letters used are H for Hertz, K for Kilohertz, M for Megahertz and G for Gigahertz.
Example: 6M25 (6.25MHz)
Next Three Symbols
The first defines the type of modulation of the main carrier. The next describes the nature of the signal modulating the carrier and the third describes the type of information being transmitted.
First Symbol- type of modulation of the main carrier
Emission in which the main carrier is amplitude modulated:
Double sideband (amplitude modulated)
Single sideband, full carrier
Single sideband, reduced carrier
Single sideband, Suppressed carrier
Emissions in which the main carrier is angle modulated:
Emission of pulses:
Unmodulated sequence of pulses
Second Symbol - nature of the signal(s) modulating the main carrier.
No modulating signal
A single channel containing quantitised or digital information without the use of a modulating sub-carrier
A single channel containing quantitised or digital information with the use of a modulating sub-carrier
A single channel containing analogue information
Two or more channels containing analogue information
Third Symbol - type of information being transmitted.
No information being transmitted
Telegraphy - for aural reception
Telegraphy for automatic reception
Data transmission, telemetry, telecommand
Combination of the above
Last Two Symbols (Optional)
- First Symbol - details of signal
Sound of commercial quality with the use of frequency inversion or bandsplitting
- Second Symbol -nature of multiplexing