science

Types of radio emissions

Types of radio emissions is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Types of radio emissions rather than just read about it. In short: The International Telecommunication Union uses an internationally agreed 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.

Key takeaways

Types of radio emissions belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Types of radio emissions to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Types of radio emissions from memory before moving on to harder problems.

Reference excerpt

The International Telecommunication Union uses an internationally agreed 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. It is based on characteristics of the signal, not on the transmitter used. 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 of the main carrier (not including any subcarriers which is why FM stereo is F8E and not D8E), 2 is a digit representing the type of modulating signal again of the main carrier, 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. This designation system was agreed at the 1979 World Administrative Radio Conference (WARC 79), and gave rise to the Radio Regulations that came into force on 1 January 1982. A similar designation system had been in use under prior Radio Regulations.

Designation details

Bandwidth The bandwidth (BBBB above) is expressed as four characters: three digits and one letter. The letter occupies the position normally used for a decimal point, and indicates what unit of frequency is used to express the bandwidth. The letter 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. The first character must be a digit between 1 and 9 or the letter H; it may not be the digit 0 or any other letter.

Type of modulation

Type of modulating signal

Types 4 and 5 were removed from use with the 1982 Radio Regulations. In previous editions, they had indicated facsimile and video, respectively.

Type of transmitted information

Details of information

Multiplexing

Common examples There is some overlap in signal types, so a transmission might legitimately be described by two or more designators. In such cases, there is usually a preferred conventional designator.

Broadcasting A3E or A3E G Ordinary amplitude modulation used for low frequency and medium frequency AM broadcasting A8E, A8E H AM stereo broadcasting. F8E, F8E H FM broadcasting for radio transmissions on VHF, and as the audio component of analogue television transmissions. Since there are generally pilot tones (subcarriers) for stereo and RDS the designator '8' is used, to indicate multiple signals. C3F, C3F N Analogue PAL, SÉCAM, or NTSC television video signals (formerly type A5C, until 1982) C7W ATSC digital television, commonly on VHF or UHF G7W DVB-T, ISDB-T, or DTMB digital television, commonly on VHF or UHF

Two-way radio A3E AM speech communication – used for aeronautical & amateur communications F3E FM speech communication – often used for marine radio and many other VHF communications 20K0 F3E Wide FM, 20.0 kHz width, ±5 kHz deviation, still widely used for amateur radio, NOAA weather radio, marine, and aviation users and land mobile users below 50 MHz 11K2 F3E Narrow FM, 11.25 kHz bandwidth, ±2.5 kHz deviation – In the United States, all Part 90 Land Mobile Radio Service (LMRS) users operating above 50 MHz were required to upgrade to narrowband equipment by 1 January 2013. 6K00 F3E Even narrower FM, future roadmap for Land Mobile Radio Service (LMRS), already required on 700 MHz public safety band J3E SSB speech communication, used on HF bands by marine, aeronautical and amateur users R3E SSB with reduced carrier (AME) speech communication, primarily used on HF bands by the military (a.k.a. compatible sideband)

Low-speed data N0N Continuous, unmodulated carrier, formerly common for radio direction finding (RDF) in marine and aeronautical navigation. A1A Signalling by keying the carrier directly, a.k.a. continuous wave (CW) or on–off keying, currently used in amateur radio. This is often but not necessarily Morse code. A2A Signalling by transmitting a modulated tone with a carrier, so that it can easily be heard using an ordinary AM receiver. It was formerly widely used for station identification of non-directional beacons, usually but not exclusively Morse code (an example of a modulated continuous wave, as opposed to A1A, above). F1B Frequency-shift keying (FSK) telegraphy, such as RTTY. F1C High frequency Radiofax F2D Data transmission by frequency modulation of a radio frequency carrier with an audio frequency FSK subcarrier. Often called AFSK/FM. J2B Phase-shift keying such as PSK31 (BPSK31)

Other P0N Unmodulated Pulse-Doppler radar

Notes

References

Further reading "Complete List of Radio Regulations". Retrieved 2011-12-17. Radio Regulations, ITU, Geneva, 1982 Radio Regulations, 2004, ITU Geneva, 2004, cf. Volume 2 - Appendices, Appendix 1 Radiocommunications Vocabulary, Recommendation ITU-R V.573-4, ITU-R, Geneva, 2000 Determination of Necessary Bandwidths Including Examples for their Calculation, Recommendation ITU-R SM.1138, Geneva, 1995 Emission characteristics of radio transmissions, Australian Communications Authority, Canberra Notes Regarding Designation of Emission, Industry Canada, 1982 Eckersley, R.J. Amateur Radio Operating Manual, 3rd edition, Radio Society of Great Britain, 1985, ISBN 0-900612-69-X

Worked examples

Example 1 — a first encounter with Types of radio emissions

Start with the simplest possible case. Write down what Types of radio emissions claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Types of radio emissions before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Types of radio emissions ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Types of radio emissions

In research: Types of radio emissions appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Types of radio emissions in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Types of radio emissions is common in secondary-school and first-year university syllabi. It links to neighbouring topics Radio communications, Radio modulation modes, so understanding it makes those chapters shorter.
In everyday life: Look for Types of radio emissions outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Types of radio emissions in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Types of radio emissions means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Types of radio emissions out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Types of radio emissions in simple terms?

Why does Types of radio emissions matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Types of radio emissions?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Types of radio emissions.