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Distance measuring equipment. In aviation, distance measuring equipment (DME) is a radio navigation technology that measures the slant range (distance) between an aircraft and a ground station by timing the propagation delay of radio signals in the frequency band between 960 and 1215 megahertz (MHz). Line-of-visibility between the aircraft and ...
44.1 kHz: Common audio sampling frequency: 10 5: 100 kHz: 740 kHz: The clock speed of the world's first commercial microprocessor, the Intel 4004 (1971) 10 6: 1 megahertz (MHz) 530 kHz to 1.710 MHz: Electromagnetic – AM radio broadcasts 1 MHz to 8 MHz: Clock speeds of early home/personal computers (mid-1970s to mid-1980s) 10 7: 10 MHz: 13.56 MHz
The hertz is defined as one per second for periodic events. The International Committee for Weights and Measures defined the second as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom" [3] [4] and then adds: "It follows that the hyperfine splitting in the ground state of the ...
V. VI. v. t. e. Very high frequency (VHF) is the ITU designation [1] for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra ...
Standard frequency and time signal-satellite service (short: SFTSS) is, according to Article 1.54 of the International Telecommunication Union's (ITU) Radio Regulations (RR), [2] defined as A radiocommunication service using space stations on earth satellites for the same purposes as those of the standard frequency and time signal service.
t. e. An audio frequency or audible frequency (AF) is a periodic vibration whose frequency is audible to the average human. The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch. [1] The generally accepted standard hearing range for humans is 20 to 20,000 Hz. [2][3][4] In air at atmospheric pressure ...
Ground wave is important for radio signals below 30 MHz, but is generally insignificant at higher frequencies where line-of-sight propagation dominates. AM and longwave broadcasting, navigation systems such as LORAN , low-frequency time signals , non-directional beacons , and short-range HF communications all make use of it.
The World Health Organization (WHO) have used ELF to refer to the concept of "extremely low frequency (ELF) electric and magnetic fields (EMF)". [17] The WHO also stated that at frequencies between 0 and 300 Hz, "the wavelengths in air are very long (6,000 km (3,700 mi) at 50 Hz and 5,000 km (3,100 mi) at 60 Hz), and, in practical situations ...