High frequency
High frequency ( HF , English RF for radio frequency ) is the designation in electrical engineering for frequencies above those of audible sound waves, which are referred to as low frequency . In technical colloquial language, the word "high frequency" is also used as a short form for high frequency voltage or power.
In acoustics , this frequency range is called ultrasound . In medicine , frequencies above 1 kHz are referred to as HF.
The classification of high-frequency and high- frequency technical systems depends on whether special physical properties are technically decisive compared to low-frequency. According to line theory , even 50 Hz high-voltage lines from a length of around 1000 km must be treated as high-frequency systems, because at this length they are already λ / 4-long lines (see Ferranti effect ).
In electrical engineering , the frequency range from 9 kHz to long-wave light (THz range) is referred to as high frequency. The EMC standard starts at 9 kHz.
This rough division of the frequency ranges is not to be confused with that which u. a. the long wave as LF, the center shaft as MF, the short-wave as HF and the ultra-short wave referred to as VHF. All of these areas are high frequency (HF) in the sense discussed here. The finer classification with English abbreviations is also used in Germany in ( amateur ) radio technology.
All systems for wireless electromagnetic communication work in the high frequency range, with a few exceptions such as Sanguine and ZEVS .
High-frequency voltage or power up to the MHz range is transmitted with coaxial cables , above about 1 GHz with waveguides . Detachable coaxial cable connections are i. d. Usually made possible by coaxial connectors .
literature
- Jürgen Detlefsen, Uwe Siart: Basics of high frequency technology . 2nd Edition. Oldenbourg Verlag, Munich Vienna 2006, ISBN 3-486-57866-9 .
- Curt Rint: Lexicon of high frequency, communications and electrical engineering. Volume 3, Verlag Technik, 1958.
- Rudolf Schiffel, Artur Köhler: Workbook high frequency technology. Basics - formula collection - data collection - components and diagrams, Franzis Verlag, Poing 2003, ISBN 978-3-7723-5520-2 .
- Walter Berndt, Werner W. Diefenbach, Kurt Kretzer: Handbook for high frequency and electrical technicians. Specialized dictionary with definitions and illustrations, Volume 5, Verlag für Radio-Foto-Kinotechnik, 1957.
Individual evidence
- ↑ Alois Krischke, Karl Rothammel : Rothammels Antennenbuch. 13th edition. DARC Verlag, Baunatal 2013, ISBN 978-3-88692-065-5 , pp. 68-72.