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European Cable Television Frequencies
These tables detail the frequencies used in European cable networks. Cable networks use frequencies which are used by different users terrestrially, like the military, police radio, etc. Because of the late introduction of cable television in Europe, older television sets generally could not receive the special cable-only channels, so some countries (like Germany) still have the rule that the public TV stations must be located either in Band I or Band III. The Hyperband was allocated later than the other cable-only channels, so television sets produced in the late 80s and early 90s may lack this band. In most cable networks, the UHF band is unusable because its frequency is too high, so TV stations are only allocated within Band I, III, the Mid-, Super- and Hyperband. Even in modern cable networks, only some UHF channels (like only channels 21-26) may be usable. This leads to a high level of congestion in many European cable TV networks, especially as analogue transmission, which is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated between the Baltic and North seas to the north, and the Alps to the south; it covers an area of , with a population of almost 84 million within its 16 constituent states. Germany borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The nation's capital and most populous city is Berlin and its financial centre is Frankfurt; the largest urban area is the Ruhr. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. In 962, the Kingdom of Germany formed the bulk of the Holy Roman Empire. During the 16th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DOCSIS
Data Over Cable Service Interface Specification (DOCSIS) is an international telecommunications standard that permits the addition of high-bandwidth data transfer to an existing cable television (CATV) system. It is used by many cable television operators to provide cable Internet access over their existing hybrid fiber-coaxial (HFC) infrastructure. History DOCSIS was originally developed by CableLabs and contributing companies, including Arris, BigBand Networks, Broadcom, Cisco, Comcast, Conexant, Correlant, Cox, Harmonic, Intel, Motorola, Netgear, Terayon, Time Warner Cable, and Texas Instruments. Versions ; : Released in March 1997, DOCSIS 1.0 included functional elements from preceding proprietary cable modems. ; : Released in April 1999, DOCSIS 1.1 standardized quality of service (QoS) mechanisms that were outlined in DOCSIS 1.0. ; (abbreviated D2) : Released in December 2001, DOCSIS 2.0 enhanced upstream data rates in response to increased demand for symmetric s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Radio
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). By mole fraction (i.e., by number of molecules), dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air composition, temperature, and atmospheric pressure vary with altitude. Within the atmosphere, air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is found only in E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Cable Television Frequencies
The Pan-American television frequencies are different for terrestrial and cable television systems. Terrestrial television channels are divided into two bands: the VHF band which comprises channels 2 through 13 and occupies frequencies between 54 and 216 MHz, and the UHF band, which comprises channels 14 through 36 and occupies frequencies between 470 and 700 MHz. These bands are different enough in frequency that they often require separate antennas to receive (although many antennas cover both VHF and UHF), and separate tuning controls on the television set. The VHF band is further divided into two frequency ranges: VHF low band (Band I) between 54 and 88 MHz, containing channels 2 through 6, and VHF high band (Band III) between 174 and 216 MHz, containing channels 7 through 13. The wide spacing between these frequency bands is responsible for the complicated design of rooftop TV antennas. The UHF band has higher noise and greater attenuation, so higher gain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
