International Classification of Emissions

The following short list of classifications of emissions is for those modes most frequently used by non-amateur ‎stations operating in the Amateur Bands and is for you guidance only. While the list is not complete it covers the ‎Minimum format to be used when submitting reports. For your further information the paper contains an extract ‎of the ITU classifications of emission for those who wish to report the full details of signals heard.‎

Some examples of symbols for the most common classes of emission.‎

 Telephony:‎
   Single side band, suppressed carrier (SSB)‎  J3E
   Frequency modulation (FM)‎   F3E
   Phase modulation (PM)‎    G3E
   Amplitude modulation (AM)‎   A3E
 
 RTTY & SITOR:‎
   Direct frequency shift keying of the carrier  F1B
   Frequency shift keyed audio tone (FM)‎  F2A
   Frequency shift keyed audio tone (SSB)‎  J2B

 Morse:‎
   On/off keying of carrier (hand sending)‎  A1A
   On/off keying of carrier for automatic reception A1B
  On/off keying of the Audio tone (FM transmitter)‎ F2A

Extract from the Radio Regulations of Article 2, Nomenclature.‎

Section III. Designation of Emissions

S2.2‎ Emissions shall be designated according to their necessary bandwidth and their classification ‎in accordance with the method described in Appendix 1.‎

Extract from the Radio Regulations of Appendix 1‎

APENDIX S1‎

Classification of Emissions and Necessary Bandwidths

‎(see Article 2)‎

Section II. Classification

‎§ 3.‎ The class of emission is a set of characteristics conforming to § 4 below.‎

‎§ 4.‎ Emissions shall be classified and symbolised according to their basic characteristics as given in Sub-‎Section IIA and any optional additional characteristics as provided for in Sub-Section IIB.‎

‎§ 5.‎ The basic characteristics (see Sub-Section IIA) are;‎

‎(1) first symbol - type of modulation of the main carrier;‎
‎(2) second symbol - nature of signal(s) modulating the main carrier;‎
‎(3) third symbol - type of information to be transmitted.‎

Modulation used only for short periods and for incidental purposes (such as, in many cases, for ‎identification or calling) may be ignored provided that the necessary bandwidth as indicated is not thereby ‎increased.‎

Sub-Section IIA. Basic Characteristics

‎§ 6.‎ ‎(1) First symbol - type of modulation of the main carrier‎
 ‎(1.1) Emission of an unmodulated carrier‎    N
 ‎(1.2) Emission in which the main carrier is amplitude-modulated ‎(including cases where sub-carriers are angle-modulated)‎ 
  ‎(1.2.1) Double-sideband      A
  ‎(1.2.2) Single-sideband, full carrier    H
  ‎(1.2.3) Single-sideband, reduced or variable level carrier  R
  ‎(1.2.4) Single-sideband, suppressed carrier    J
  ‎(1.2.5) Independent sidebands     B
  ‎(1.2.6) Vestigial sidebands‎     C
  ‎(1.3) Emission in which the main carrier is angle-modulated
  ‎(1.3.1) Frequency modulation‎     F
  ‎(1.3.2) Phase Modulation‎      G
 ‎ (1.4) Emission in which the main carrier is amplitude - and‎ angle-modulated either simultaneously or in a pre-established sequence      D

 ‎(1.5) Emission of pulses2‎
   ‎(1.5.1) Sequence of unmodulated pulses‎    P
  ‎ (1.5.2) A sequence of pulses‎
   ‎(1.5.2.1) modulated in amplitude‎    F
   ‎(1.5.2.2) modulated in width/duration‎   L
   ‎(1.5.2.3) modulated in position/phase‎   M
   ‎(1.5.2.4) in which the carrier is angle modulated‎
    ‎ during the angle-period of the pulse  Q
   ‎(1.5.2.5) which is a combination of the forgoing‎
    ‎ or is produced by other means‎   V
 ‎(1.6) Cases not covered above, in which an emission consists of
  ‎ the main carrier modulated, either simultaneously or in a‎
  ‎ pre-established sequence, in a combination of tow or more of
  ‎ the following modes; amplitude, angle, pulse‎   W
 ‎(1.7) Cases not otherwise covered‎     X
    
‎2Emissions where the main carrier is directly modulated by a signal which has been coded into ‎quantized form (e.g. pulse code modulation) should be designated under (1.2) or (1.3)‎

‎§ 6.‎ ‎(2) Second symbol - nature of signals(s) modulating the main carrier
  ‎(2.1) No modulating signal‎      ‎0‎
  ‎(2.2) A single channel containing quantized or digital information‎
   without the use of a modulating sub-carrier3‎   ‎1‎
  ‎(2.3) A single channel containing quantized or digital information‎
   with the use of a modulating sub-carrier3‎    ‎2‎
  ‎(2.4) A single channel containing analogue information‎   ‎3‎
  ‎(2.5) Two or more channels containing quantized or digital‎
   ‎ information‎       ‎7‎
  ‎(2.5) Two or more channels containing analogue information ‎  ‎8‎
  ‎(2.7) Composite system with one or ,more channels containing
   ‎ quantized or digital information, together with one or more‎
   ‎ channels containing analogue information‎    ‎9‎
  ‎(2.8) Cases not otherwise covered‎     X
    
 ‎3 This excludes time-division multiplex.‎
‎§ 6.‎ ‎(3) Third Symbol - type of information to be transmitted‎
  ‎(3.1) No information transmitted‎     N
  ‎(3.2) Telegraphy - for aural reception‎     A
  ‎(3.3) Telegraphy - for automatic reception‎    B
  ‎(3.4) Facsimile‎       C
  ‎(3.5) Data transmission, telemetry, telecommand    D
  ‎(3.6) Telephony (including sound broadcasting)‎    E
  ‎(3.7) Television (video)‎      F
  ‎(3.8) Combination of above‎      W
  ‎(3.9) Cases not otherwise covered‎     X

    
 ‎4 In this context the word ‘information’ does not include information of a constant, unvarying nature ‎such as is provided by standard frequency emissions, continuous wave and pulse radar. etc.‎

Sub-Section IIB. Optional Characteristics for the Classification of Emissions

‎§ 7.‎  Two optional characteristic should be added for a more complete description of an
emission. These are (see also Recommendation 62)‎
   Fourth symbol - Details of signal(s)‎
   Fifth symbol - Nature of multiplexing‎
   Where the fourth or fifth symbol is used it shall be as indicated below.‎
   Where the fourth or fifth symbol is not used this should be indicated by a dash where each ‎symbol would otherwise appear

‎§ 7.‎ ‎(1)‎ Fourth symbol - Details of signal(s)‎
  ‎(1.1)‎ Two-condition code with elements of differing numbers and/or
   durations       A
  ‎(1.2)‎ Two-condition code with elements of the same number and
   duration without error correction     B
  ‎(1.3)‎ Two-condition code with elements of the same number and
   duration with error correction     C
  ‎(1.4)‎ Four-condition code in which each condition represents a ‎
   signal element (of one or more bits)‎    D
  ‎(1.5)‎ Multi-condition code in which each condition represents a ‎
   signal element (or one or more bits)‎    E
  ‎(1.6)‎ Multi-condition code in which each condition or combination
   of conditions represents a character    F
  ‎(1.7)‎ Sound of broadcasting quality (monophonic)‎   G
  ‎(1.8)‎ Sound of broadcasting quality (stereophonic or quadraphonic)‎ H
  ‎(1.9)‎ Sound of commercial quality (excluding categories given in
   sub-paragraphs 1.10 and 1.11)‎     J
  ‎(1.10)‎ Sound of commercial quality with the use of frequency
   inversion or band splitting     K
  ‎(1.11)‎ Sound of commercial quality with separate frequency- modulated‎
   signals to control the level of demodulated signal   L
  ‎(1.12)‎ Monochrome       M
  ‎(1.13)‎ Colour       N
  ‎(1.14)‎ Combination of the above     W
  ‎(1,15)‎ Cases not otherwise covered     X
‎§ 7.‎ ‎(2)‎ Fifth symbol - Nature of Multiplexing‎
  ‎(2.1)‎ None        N
  ‎(2.2)‎ Code-division multiplex5‎     C
  ‎(2.3)‎ Frequency-division multiplex     F
  ‎(2.4)‎ Time-division multiplex     T
  ‎(2.5)‎ Combination of frequency-division multiplex and time-division
   multiplex       W ‎
  ‎(2.6)‎ Other types of multiplexing     X
     
 ‎5 This includes bandwidth expansion technique