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Classes of radio emission - this page is a stub

In the past, the type of modulation of a transmitter or receiver, was specified as an abbreviation, such as AM for Amplitude Modulation, or FM for Frequency modulation. In the late 1970s, the designators for all modulation types were standardised by the International Telecommunication Union (ITU), resulting in a complex scheme of confusing identifiers that changed over time [1].

The new designators follow a scheme that has been agreed by the telecom authorities of most countries, and cover even the most complex modern digital modulation types. Confusingly how­ever, it does not discriminate between Lower Side Band (LSB) and Upper Side Band (USB), which is why many radio amateurs and professionals are still using the original (legacy) designators. 1

  1. LSB and USB are both covered by J3E (formerly A3J), the designator for Single Side Band (SSB) with suppressed carrier.  Wikipedia

Some examples
Below is a non-exhaustive overview of radio frequency (RF) modulation types that are used with some of the equipment described on this website. The list may be expanded in the future and suggestions for improvement are welcome. For a more complete overview, see  Wikipedia.

New Old Legacy Description
A0N A0 CW Telegraphy without modulated subcarrier
A1A A1 CW Continuous Wave, or AM ON/OFF keying
A1B A1 RTTY Radio Teletype
A2A A2 MCW Modulated tone with carrier
A3E A3 AM Amplitude Modulation
F1A F1 CW Telegraphy with frequency shift keying
F1B F1 FSK Frequency Shift Keying - Radio Teletype (RTTY)
F1C F4 FAX Facsimile
F3C F4 FAX Facsimile
F3E F3 FM Frequency Modulation
F7B F6 MFSK Multi-Frequency Shift Keying
H3E A3H SSB Single Sideband with full carrier
J2A A2J CW Telegraphy, modulated tone, suppressed carrier
J2B A2J PSK Phase-shift keying, e.g. PSK31 (BPSK31)
J3E A3J SSB Single Side Band (USB or LSB), suppressed carrier
J7B - DSB Double Side Band (independently modulated sidebands)
R3E - VSB Vestigial Side Band, Single Side Band, reduced carrier
Common legacy modulation types
  • AM
    Amplitude Modulation
  • FM
    Frequency Modulation
  • SSB
    Single Side Band (either LSB or USB)
  • LSB
    Lower Side Band
  • USB
    Upper Side Band
  • PPM
    Pulse Position MNodulation
Modulation types
  • PSK
    Phase Shift Keying
  • QPSK
    Quadrature Phase Shift Keying
    Differential Quadrature Phase Shift Keying
Pulse Position Modulation   PPM

  1. Wikipedia, Types of radio emissions
    Retrieved April 2020.

  2. R&S manual of Transmission Methods
    4070.0711.02-03. Rohde & Schwarz, München (Germany) 2014.

  3. Utility DX-ers Forum (UDXF) website
    Retrieved March 2021.
Further information
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Crypto Museum. Created: Sunday 26 April 2020. Last changed: Sunday, 05 November 2023 - 15:36 CET.
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