Modulation type
The type of modulation of a radio signal is the method that describes how the desired useful signal is modulated onto a carrier signal . Modulation types are classified according to a template from the International Telecommunication Union (ITU). A nine-character scheme is used for this, which is structured as follows: BBBBMSIDX
- BBBB: bandwidth of the signal, e.g. B. 6K00 (6.00 kHz)
- M: type of modulation, e.g. B. A (amplitude modulation)
- S: type of signal, e.g. B. 3 ( analog signal )
- I: type of information, e.g. B. E (telephony, also broadcasting)
- D: detailing (optional), e.g. B. G (monophone)
- X: multiplex method (optional), e.g. B. N (no multiplex)
The example 6K00A3EGN denotes e.g. B. an amplitude-modulated , analog , monophonic broadcast signal with a bandwidth of 6 kHz, as z. B. is typical for medium wave and short wave radio transmitters .
Bandwidth, detailing and multiplexing methods are often left out so that the designation consists of only three characters (MSI), e.g. B. A3E.
Please note that some modulation identifiers are equivalent and indistinguishable. The difference comes from the type of processing. So z. B. for a frequency shift keying of the oscillator of a transmitter, whereby the frequency jumps back and forth between two values (FSK, Frequency Shift Keying). The same is achieved by keying an LF oscillator and modulating a J3E transmitter with this analog signal (AFSK, Audio Frequency Shift Keying).
Bandwidth
The bandwidth is indicated by three digits and a letter. The letter can be an H (Hertz), a K (kHz), an M (MHz) or a G (GHz). The letter is in place of the comma.
| Area | Letter | Smallest value | Greatest value | example |
|---|---|---|---|---|
| 0.001 Hz ... 999 Hz | H | H001 | 999H | 25H3: 25.3 Hz |
| 1 kHz ... 999 kHz | K | 1K00 | 999K | 2K40: 2.4 kHz |
| 1 MHz ... 999 MHz | M. | 1M00 | 999M | 1M25: 1.25 MHz |
| 1 GHz… 999 GHz | G | 1G00 | 999G | 5G65: 5.65 GHz |
Modulation type of the main carrier
| character | meaning | example |
|---|---|---|
| N | No modulation | |
| A. | Amplitude modulation | Long, medium or shortwave broadcast signal |
| H | Amplitude modulation ( single sideband modulation , full carrier) | Distress call |
| R. | Amplitude modulation (single sideband modulation, reduced carrier) | |
| J | Amplitude modulation (single sideband modulation, suppressed carrier) | Radiotelephony signal in short-wave long-distance traffic (commercial, military or amateur radio service ) |
| B. | Amplitude modulation with different sidebands | |
| C. | Amplitude modulation, vestigial sideband modulation | Analog television |
| D. | Amplitude modulation, angle modulation | WIRELESS INTERNET ACCESS |
| F. | Angle modulation, frequency modulation | FM broadcasting |
| G | Angle modulation, phase modulation | |
| P | Unmodulated pulse train | RADAR |
| K | Amplitude modulated pulses | Remote control, telemetry |
| L. | Width-modulated pulses (pulse duration) | Remote control, telemetry |
| M. | Phase modulated pulses (pulse position) | Remote control, telemetry |
| Q | Carrier phase modulated during a pulse | |
| V | Combinations of the above modulations or methods that are not based on one
Modulation of amplitude, frequency / phase or pulse properties are based. |
|
| W. | Cases not listed above in which the method consists of at least two simultaneous or sequential methods from amplitude, frequency / phase or pulse properties. | |
| X | Everything else |
Signal type
| character | meaning | example |
|---|---|---|
| 0 | No modulating signal | |
| 1 | Single-channel digital or quantized signal without
Use of an auxiliary beam |
Teletype, FSK (Frequency Shift Keying), the carrier frequency
is modulated |
| 2 | Single-channel digital or quantized signal with
an auxiliary carrier |
Teletype, AFSK (audio FSK), with an analog signal being used
a single sideband transmitter modulates |
| 3 | Single-channel analog signal | Monophonic broadcast |
| 7th | Multi-channel digital or quantized signal | Two-channel teletype |
| 8th | Multi-channel analog signal | Stereo broadcasting |
| 9 | Mixed signal | |
| X | Everything else |
Information type
| character | meaning | example |
|---|---|---|
| N | No information | |
| A. | Telegraphy for aural recording | Morse code |
| B. | Telegraphy for machine reception | Teletype |
| C. | fax | Weather maps |
| D. | Data, telemetry, remote control | autom. Weather measuring stations |
| E. | Telephony, radio | |
| F. | Television signal | |
| W. | Mixtures of the above types of information | |
| X | Everything else |
Detailing (optional)
A distinction is made between signals with two or more discrete states, sound and television signals.
| character | meaning | example |
|---|---|---|
| A. | Binary code with varying number of elements or character duration | Morse code |
| B. | Binary code with constant number of elements / character duration, without error detection / correction | ASCII code without parity bit |
| C. | Binary code with constant number of elements / character duration, with error detection / correction | ASCII code with parity bit |
| D. | Code with four states, each representing a signal element
or one or more bits |
Two-channel teletype |
| E. | Like D, but more than four states. | Analog modem |
| F. | Like E, but one character per state | Piccolo Teletype : One tone per letter. |
| G | Single channel broadcast signal | Medium wave transmitter |
| H | Two or more channel radio signal | FM stereo transmitter |
| J | Simple quality sound signal | CB radio |
| K | Simple quality sound signal with frequency inversion or band division | Analog radio for authorities |
| L. | Simple quality sound signal with additional frequency-modulated
Information about amplitude control |
|
| M. | Monochrome television signal | Surveillance cameras |
| N | Colored television signal | watch TV |
| W. | Combinations | |
| X | Others |
Multiplex information
| character | meaning |
|---|---|
| N | No multiplex signal |
| C. | Code division multiplex |
| F. | Frequency division multiplex |
| T | Time division multiplex |
| W. | Combinations |
| X | Others |
Frequently used types of modulation
- A1A: Morse code with keyed carrier (old A1)
- A2A: Morse code with modulated subcarrier (old A2)
- A3E: amplitude-modulated telephony signal (old A3)
- A3F: amplitude-modulated video signal (old A5)
- J3E: SSB single sideband modulation (LSB / USB) (old A3j)
- F1B: frequency-modulated teletype telegraphy through keyed carrier (old F1)
- F1C: frequency-modulated facsimile transmission through keyed carrier (old F4)
- F1D: frequency-modulated telecontrol through keyed carrier (old F9)
- F2A: frequency-modulated Morse code with a modulated subcarrier (old F2)
- F2B: frequency-modulated teletype telegraphy with a modulated subcarrier (old F2)
- F2C: frequency-modulated facsimile transmission with a modulated subcarrier (old F4)
- F2D: frequency-modulated telecontrol with a modulated subcarrier (old F9)
- F3C: analog frequency-modulated facsimile signal (old F4)
- F3E: frequency-modulated telephony (old F3)
- F3F: frequency-modulated video signal (old F5)
- G1A: phase-modulated Morse code without auxiliary carrier
- G1B: phase modulated telex without subcarrier
- G1C: phase modulated fax transmission without subcarriers
- G1D: phase-modulated data transmission without subcarriers
- G2A: phase-modulated Morse code with auxiliary carrier
- G2B: phase-modulated telex with subcarrier
- G2C: phase modulated fax transmission with subcarrier
- G2D: phase-modulated data transmission with subcarrier
- G3C: phase modulated fax transmission
- G3E: phase modulated telephony
- G3F: phase modulated video transmission
literature
- Hans Georg Möller: The physical basics of high frequency technology. 3rd edition, Springer Verlag, Berlin Heidelberg 1955.
- Ralf Gessler, Thomas Krause: Wireless networks for the local area. 2nd edition, Springer Fachmedien, Wiesbaden 2014, ISBN 978-3-8348-1239-1 .
- HH Meinke, Friedrich-Wilhelm Gundlach, Klaus Lange, Karl-Heinz Locher: Pocket book of high frequency technology. Volume 3 systems, Springer Verlag, Berlin / Heidelberg 1992, ISBN 978-3-540-54716-7 .
- Erwin Hölzler, Dietwald Thierbach (ed.): News transmission. Basics and technology, Springer-Verlag, Berlin / Heidelberg 1966.
- Andres Keller: Broadband cables and access networks. Technical principles and standards. Springer-Verlag, Berlin / Heidelberg 2011, ISBN 978-3-642-17631-9 .
Web links
- "Classification of emissions and necessary bandwidths" , Appendix I, WRC-12 of the ITU (accessed on July 28, 2019)
- The types of modulation - theory and practical applications (accessed on September 14, 2017)
- International system of modulation type designations (accessed on September 14, 2017)
- Method for classifying the type of modulation of a data signal (accessed September 14, 2017)
- Wireless audio transmission (accessed September 14, 2017)