Types of radio emissions

The International Telecommunication Union uses a special system for classifying radio frequency signals. Each type of radio emission is classified according to its bandwidth, method of modulation, nature of the modulating signal, and type of information transmitted on the carrier signal.

An emission designation is of the form BBBB 123 45, where BBBB is the bandwidth of the signal, 1 is a letter indicating the type of modulation used, 2 is a digit representing the type of modulating signal, 3 is a letter corresponding to the type of information transmitted, 4 is a letter indicating the practical details of the transmitted information, and 5 is a letter that represents the method of multiplexing. The 4 and 5 fields are optional.

Contents

1 Designation details

1.1 Bandwidth
1.2 Type of modulation
1.3 Type of modulating signal
1.4 Type of transmitted information
1.5 Details of information
1.6 Multiplexing

Designation details

Bandwidth

The bandwidth is expressed as three digits and a letter that occupies the position normally used for a decimal point. The letter indicates what unit of frequency is used to express the bandwidth. H indicates Hertz, K indicates kilohertz, M indicates megahertz, and G indicates gigahertz. For instance, "500H" means 500 Hz, and "2M50" means 2.5 MHz.

Type of modulation

N	Unmodulated carrier
A	Double-sideband amplitude modulation (AM broadcast radio)
H	Single-sideband with full carrier (used by CHU)
R	Single-sideband with attenuated carrier
J	Single-sideband with no carrier (Shortwave utility and amateur stations)
B	Two sidebands containing different signals
C	Vestigial sideband (e.g. NTSC)
F	Frequency modulation (FM broadcast radio)
G	Phase modulation
D	Combination of AM and FM or PM
P	Sequence of pulses without modulation
K	Pulse amplitude modulation
L	Pulse width modulation (used by WWVB)
M	Pulse position modulation
Q	Sequence of pulses, phase or frequency modulation within each pulse
V	Combination of pulse modulation methods
W	Combination of any of the above
X	None of the above

Type of modulating signal

0	No modulating signal
1	One channel containing digital information, no subcarrier
2	One channel containing digital information, using a subcarrier
3	One channel containing analogue information
7	More than one channel containing digital information
8	More than one channel containing analogue information
9	Combination of analogue and digital channels
X	None of the above

Type of transmitted information

N	No transmitted information
A	Aural telegraphy (Morse code)
B	Electronic telegraphy (Radioteletype and digital modes)
C	Facsimile (Still images)
D	Telemetry or Telecommand (Remote control)
E	Telephony (voice or audio signals)
F	Video (television signals)
W	Combination of any of the above
X	None of the above

Details of information

A	Two-condition code, elements vary in quantity and duration
B	Two-condition code, elements fixed in quantity and duration
C	Two-condition code, elements fixed in quantity and duration, error-correction included
D	Four-condition code, one condition per "signal element"
E	Multi-condition code, one condition per "signal element"
F	Multi-condition code, one character represented by one or more conditions
G	Monophonic broadcast-quality sound
H	Stereophonic or quadraphonic broadcast-quality sound
J	Commercial-quality sound (non-broadcast)
K	Commercial-quality sound—frequency inversion and-or "band-splitting" employed
L	Commercial-quality sound, independent FM signals, such as pilot tones, used to control the demodulated signal
M	Greyscale images or video
N	Full-color images or video
W	Combination of two or more of the above
X	None of the above

Multiplexing

N	None used
C	Code-division (excluding spread spectrum)
F	Frequency-division
T	Time-division
W	Combination of Frequency-division and Time-division
X	None of the above

Categories: Radio modulation modes | Radio

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