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Dynamic Carrier Control
Dynamic carrier control (DCC) is a method of reducing power consumption in radio transmitters during periods of low audio activity or silence. It is a type of Modulation-Dependent Carrier Level control, or MDCL. All modern high-power (>50 kW) shortwave radio transmitters incorporate DCC of some kind, as well as some mediumwave (MW) transmitters. DCC causes the carrier wave level to be automatically reduced when the audio is very weak or no audio is present. During periods of silence (no audio), the carrier power is reduced by 50%, so the 250 kW transmitter is putting out a carrier of 125 kW during audio pauses. This carrier power reduction saves electricity. History This amplitude modulation (and vestigial SSB modulation) energy-saving mode was devised in the late 1930s. The system was originally referred to as the Hapsburg Carrier System. DCC was not implemented in transmitter designs until the 1980s, because of some of the complexities of the control circuit. * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Radio Transmitter
In electronics and telecommunications, a radio transmitter or just transmitter (often abbreviated as XMTR or TX in technical documents) is an electronic device which produces radio waves with an antenna with the purpose of signal transmission to a radio receiver. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves. Transmitters are necessary component parts of all electronic devices that communicate by radio, such as radio (audio) and television broadcasting stations, cell phones, walkie-talkies, wireless computer networks, Bluetooth enabled devices, garage door openers, two-way radios in aircraft, ships, spacecraft, radar sets and navigational beacons. The term ''transmitter'' is usually limited to equipment that generates radio waves for communication purposes; or radiolocation, such as radar and navigational transmitters. Generators of radio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Open Market
The term open market is used generally to refer to an economic situation close to free trade. In a more specific, technical sense, the term refers to interbank trade in securities. In economic theory Economists judge the "openness" of markets according to the amount of government regulation of those markets, the scope for competition, and the absence or presence of local cultural customs which get in the way of trade. In principle, a fully open market is a completely free market in which all economic actors can trade without any external constraint. In reality, few markets exist which are open to that extent, since they usually cannot operate without an enforceable legal framework for trade which guarantees security of property, the fulfillment of contractual obligations associated with transactions, and the prevention of cheating. A physical open market is a space where anyone wishing to trade physical goods may do so free of selling charges and taxes, and has come to be regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Telefunken
Telefunken was a German radio and television producer, founded in Berlin in 1903 as a joint venture between Siemens & Halske and the ''AEG (German company), Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ("General electricity company"). Prior to World War I, the company set up the first world-wide network of communications and was the first in the world to sell electronic televisions with cathode-ray tubes, in Germany in 1934. The brand had several incarnations: * ''Gesellschaft für drahtlose Telegraphie Gesellschaft mit beschränkter Haftung, m.b.H., System Telefunken'', founded in 1903 as a joint venture between AEG and Siemens & Halske * ''Telefunken, Gesellschaft für drahtlose Telegraphie m.b.H.'', in 1923; since 1941 as subsidiary of AEG alone * ''Telefunken Gesellschaft mit beschränkter Haftung, GmbH'', in 1955 * ''Telefunken Aktiengesellschaft (AG)'', in 1963 * ''Allgemeine Elektrizitäts-Gesellschaft AEG-Telefunken'', created in 1967 through a merger between Telefunken ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
RIZ (company)
RIZ is a Croatian electronics company headquartered in Zagreb. It was founded in 1948 as Radio Industrija Zagreb. It began manufacturing radios, Phonograph, gramophones, television sets, semiconductors (transistors, integrated circuits, capacitors) as well as military transmission devices. Currently, it only manufactures transmitters, Antenna (radio), antennas and electronic electricity meters. They manufactured the first TV in Yugoslavia, TV 101, from a licence by Philips in 1955. History The company was founded on 24 December 1948 by a team of experts from ''Radio Zagreb'' (today Croatian Radio) under a state decree for the purpose of manufacturing and servicing transmitters for the provider. It was originally a partner of a state institution called 'Composite Organisation of Associated Labour' with about 50 employees. A year after its founding, they produced their first 15 kW mid-wave transmitter called 'Učka', which began mass production in 1952. Shortly after that, they branch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Nautel
Nautel Ltd. is a Canadian manufacturer of AM and FM radio broadcast transmitters, navigational radio beacons, Differential Global Positioning System (DGPS) transmitters, NOAA Weather Radio, NOAA weather radio transmitters, LF PNT/Loran-C#eLORAN, eLORAN transmitters, Sonar, SONAR high-power low-frequency amplifiers and Sonar, SONAR systems, medium frequency (MF) telegraph and NAVTEX transmitters, and high frequency (HF) amplifiers for dielectric heating applications. Nautel was the first company to develop a commercially available, fully Solid state (electronics), solid-state AM broadcast transmitter. History Nautel was founded in 1969 in the rural community of Hackett's Cove, Nova Scotia. Its primary operation was building and supplying solid state navigation Beacon, beacons for the Canadian government. In an effort to better serve the US market, Nautel Maine Inc., a wholly owned subsidiary located in Bangor, Maine, Bangor, Maine, was founded in 1974. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Continental Electronics
Continental Electronics is an American manufacturer of broadcast and military radio transmitters, based in Dallas, Texas. Although Continental today is best known for its FM, shortwave, and military VLF transmitters, Continental is most significant historically for its line of mediumwave ( AM) transmitters, many of which are still in active service as either main transmitters or backup facilities. Among clear-channel AM stations in the U.S. and Canada, the Continental 317C was the most popular transmitter type in the 1970s and 1980s. History Continental Electronics was founded in Dallas in 1946 by James O. Weldon, as a spin-off of the broadcast consulting business in which he was a partner, Weldon & Carr. In 1953, when Western Electric's radio equipment business was broken up by Federal antitrust regulators, Continental acquired the AM transmitter business, and with it the U.S. patent on the Doherty linear RF amplifier. Continental became part of Ling-Temco-Vought in about 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Thales Group
Thales S.A., Trade name, trading as Thales Group (), is a French multinational corporation, multinational aerospace and defence industry, defence corporation specializing in electronics. It designs, develops and manufactures a wide variety of aerospace and military systems, devices and equipment but also operates in the computer security, cybersecurity and formerly civil ground transportation sectors. The company is headquartered in Paris' business district, La Défense, and its stock is listed on Euronext Paris. Founded as Thomson-CSF in 1968, the group was rebranded ''Thales'' (named after the Greek philosopher Thales , pronounced as in French language, French) in 2000 due to the company's desire to simplify and improve the group's brand. Thales is partially owned by the Agence des participations de l'État, French state and operates in more than 68 countries. In 2023, the company generated €18,42 billion in revenue and was the 17th largest defence contractor in the world, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Skywave
In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. Since it is not limited by the curvature of the Earth, skywave propagation can be used to communicate beyond the horizon, at intercontinental distances. It is mostly used in the shortwave frequency bands. As a result of skywave propagation, a signal from a distant AM broadcasting station, a shortwave station, or – during sporadic E propagation conditions (principally during the summer months in both hemispheres) – a distant VHF FM or TV station can sometimes be received as clearly as local stations. Most long-distance shortwave ( high frequency) radio communication – between 3 and 30 MHz – is a result of skywave propagation. Since the early 1920s amateur radio operators (or "hams"), limited to lower transmitter power than broadcast statio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
FM Stereo
FM broadcasting is a method of radio broadcasting that uses frequency modulation (FM) of the radio broadcast carrier wave. Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to transmit high-fidelity sound over broadcast radio. FM broadcasting offers higher fidelity—more accurate reproduction of the original program sound—than other broadcasting techniques, such as AM broadcasting. It is also less susceptible to common forms of interference, having less static and popping sounds than are often heard on AM. Therefore, FM is used for most broadcasts of music and general audio (in the audio spectrum). FM radio stations use the very high frequency range of radio frequencies. Broadcast bands Throughout the world, the FM broadcast band falls within the VHF part of the radio spectrum. Usually 87.5 to 108.0 MHz is used, or some portion of it, with few exceptions: * In the former Soviet republics, and some former Eastern Bloc countr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Frequency Modulation
Frequency modulation (FM) is a signal modulation technique used in electronic communication, originally for transmitting messages with a radio wave. In frequency modulation a carrier wave is varied in its instantaneous frequency in proportion to a property, primarily the instantaneous amplitude, of a message signal, such as an audio signal. The technology is used in telecommunications, radio broadcasting, signal processing, and Run-length limited#FM: .280.2C1.29 RLL, computing. In Analog signal, analog frequency modulation, such as radio broadcasting of voice and music, the instantaneous frequency deviation, i.e. the difference between the frequency of the carrier and its center frequency, has a functional relation to the modulating signal amplitude. Digital data can be encoded and transmitted with a type of frequency modulation known as frequency-shift keying (FSK), in which the instantaneous frequency of the carrier is shifted among a set of frequencies. The frequencies m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders of Russia, land borders with fourteen countries. Russia is the List of European countries by population, most populous country in Europe and the List of countries and dependencies by population, ninth-most populous country in the world. It is a Urbanization by sovereign state, highly urbanised country, with sixteen of its urban areas having more than 1 million inhabitants. Moscow, the List of metropolitan areas in Europe, most populous metropolitan area in Europe, is the capital and List of cities and towns in Russia by population, largest city of Russia, while Saint Petersburg is its second-largest city and Society and culture in Saint Petersburg, cultural centre. Human settlement on the territory of modern Russia dates back to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Manufacturer
Manufacturing is the creation or Production (economics), production of goods with the help of equipment, Work (human activity), labor, machines, tools, and chemical or biological processing or formulation. It is the essence of the secondary sector of the economy. The term may refer to a range of Human behavior, human activity, from handicraft to High tech manufacturing, high-tech, but it is most commonly applied to industrial design, in which raw materials from the primary sector of the economy, primary sector are transformed into finished goods on a large scale. Such goods may be sold to other manufacturers for the production of other more complex products (such as aircraft, Major appliance, household appliances, furniture, sports equipment or automobiles), or distributed via the tertiary industry to end users and consumers (usually through wholesalers, who in turn sell to retailers, who then sell them to individual customers). Manufacturing engineering is the field of engine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
