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Radio Networks
There are two types of radio network currently in use around the world: the one-to-many (simplex communication) broadcast network commonly used for public information and mass-media entertainment, and the two-way radio (duplex communication) type used more commonly for public safety and public services such as police, fire, taxicabs, and delivery services. Cell phones are able to send and receive simultaneously by using two different frequencies at the same time. Many of the same components and much of the same basic technology applies to all three. The two-way type of radio network shares many of the same technologies and components as the broadcast-type radio network but is generally set up with fixed broadcast points (transmitters) with co-located receivers and mobile receivers/transmitters or transceivers. In this way both the fixed and mobile radio units can communicate with each other over broad geographic regions ranging in size from small single cities to entire states/provi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simplex Communication
Simplex communication is a communication channel that sends information in one direction only."Simplex" ''The IEEE Authoritative Dictionary of Standard Terms, 7th Ed.'', 2000, Inst. of Electrical and Electronic Engineers, p.1053 The International Telecommunication Union definition is a communications channel that operates in one direction at a time, but that may be reversible; this is termed half duplex in other contexts. A duplex communication channel requires two simplex channels operating in opposite directions at the same time. For example, in TV and radio broadcasting, information flows only from the transmitter site to multiple receivers. A pair of walkie-talkie two-way radios provide a simplex circuit in the ITU sense; only one party at a time can talk, while the other listens until it can hear an opportunity to transmit. The transmission medium (the radio signal over the air) can carry information in only one direction. The old Western Union company used the term simpl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Funding
A subsidy or government incentive is a form of financial aid or support extended to an economic sector (business, or individual) generally with the aim of promoting economic and social policy. Although commonly extended from the government, the term subsidy can relate to any type of support – for example from NGOs or as implicit subsidies. Subsidies come in various forms including: direct (cash grants, interest-free loans) and indirect ( tax breaks, insurance, low-interest loans, accelerated depreciation, rent rebates). Furthermore, they can be broad or narrow, legal or illegal, ethical or unethical. The most common forms of subsidies are those to the producer or the consumer. Producer/production subsidies ensure producers are better off by either supplying market price support, direct support, or payments to factors of production. Consumer/consumption subsidies commonly reduce the price of goods and services to the consumer. For example, in the US at one time it was cheaper to bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coaxial Cable
Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a protective outer sheath or jacket. The term '' coaxial'' refers to the inner conductor and the outer shield sharing a geometric axis. Coaxial cable is a type of transmission line, used to carry high-frequency electrical signals with low losses. It is used in such applications as telephone trunk lines, broadband internet networking cables, high-speed computer data busses, cable television signals, and connecting radio transmitters and receivers to their antennas. It differs from other shielded cables because the dimensions of the cable and connectors are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a transmission line. Coaxial cable was used in the first (1858) and fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequency, frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both Ultra high frequency, UHF and Extremely high frequency, EHF (millimeter wave) bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 0.3 m and 3 mm). In all cases, microwaves include the entire Super high frequency, SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum. Frequencies in the microwave range are often referred to by their Radio band#IEEE, IEEE radar band designations: S band, S, C band (IEEE), C, X band, X, Ku band, Ku, K band (IEEE), K, or Ka band, Ka band, or by similar NATO or EU designations. The prefix ' in ''microwave'' is not meant to suggest a wavelength in the M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FM Broadcasting
FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is capable of higher fidelity—that is, more accurate reproduction of the original program sound—than other broadcasting technologies, such as AM broadcasting. It is also less susceptible to common forms of interference, reducing static and popping sounds often heard on AM. Therefore, FM is used for most broadcasts of music or 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 thereof, with few exceptions: * In the former Soviet republics, and some former Eastern Bloc countries, the older 65.8–74 M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upstate New York
Upstate New York is a geographic region consisting of the area of New York State that lies north and northwest of the New York City metropolitan area. Although the precise boundary is debated, Upstate New York excludes New York City and Long Island, and most definitions of the region also exclude all or part of Westchester and Rockland counties, which are typically included in Downstate New York. Major cities across Upstate New York from east to west include Albany, Utica, Binghamton, Syracuse, Rochester, and Buffalo. Upstate New York is divided into several subregions: the Hudson Valley (of which the lower part is sometimes debated as to being "upstate"), the Capital District, the Mohawk Valley region, Central New York, the Southern Tier, the Finger Lakes region, Western New York, and the North Country. Before the European colonization of the United States, Upstate New York was populated by several Native American tribes. It was home to the Iroquois Confederacy, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rural Radio Network
The Rural Radio Network (RRN) was an interconnected group of six commercial FM radio stations spread across upstate New York and operated from Ithaca, New York -- the first all-radio, no-wireline network in the world. It began operation in 1948 as an innovative broadcast service to the agricultural community, but competition from television—and a lack of affordable, well-performing FM receivers—caused the founders' original business plan to fail. The stations changed ownership, as well as Radio formats, several times in futile attempts to achieve profitability. Perhaps the group's most notable owner was the Christian Broadcasting Network, headed by televangelist Pat Robertson, which acquired the stations through a corporate donation in 1969. A decade later, Robertson decided to sell the stations and the licenses were gradually transferred to individual owners in 1981 and 1982, thus dissolving one of the nation's earliest FM networks. Network history through 1981 Planning ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gramophone Record
A phonograph record (also known as a gramophone record, especially in British English), or simply a record, is an analog sound storage medium in the form of a flat disc with an inscribed, modulated spiral groove. The groove usually starts near the periphery and ends near the center of the disc. At first, the discs were commonly made from shellac, with earlier records having a fine abrasive filler mixed in. Starting in the 1940s polyvinyl chloride became common, hence the name vinyl. The phonograph record was the primary medium used for music reproduction throughout the 20th century. It had co-existed with the phonograph cylinder from the late 1880s and had effectively superseded it by around 1912. Records retained the largest market share even when new formats such as the compact cassette were mass-marketed. By the 1980s, digital media, in the form of the compact disc, had gained a larger market share, and the record left the mainstream in 1991. Since the 1990s, records con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from el, τῆλε (''tēle'', ''far'') and φωνή (''phōnē'', ''voice''), together meaning ''distant voice''. A common short form of the term is ''phone'', which came into use early in the telephone's history. In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. The essential elements of a telephone are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Chain (signal Processing Chain)
Signal chain, or signal-processing chain is a term used in signal processing and mixed-signal system design to describe a series of signal-conditioning electronic components that receive input (data acquired from sampling either real-time phenomena or from stored data) sequentially, with the output of one portion of the chain supplying input to the next. Signal chains are often used in signal processing applications to gather and process data or to apply system controls based on analysis of real-time phenomena. Definition This definition comes from common usage in the electronics industry and can be derived from definitions of its parts:Sippi, C. & Sippi, P., Computer Dictionary and Handbook, 1972, Bobbs-Merrill, New York, *Signal: "The event, phenomenon, or electrical quantity, that conveys information from one point to another". *Chain: "1. Any series of items linked together. 2. Pertaining to a routine consisting of segments which are run through the computer in tandem, onl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advertising
Advertising is the practice and techniques employed to bring attention to a product or service. Advertising aims to put a product or service in the spotlight in hopes of drawing it attention from consumers. It is typically used to promote a specific good or service, but there are wide range of uses, the most common being the commercial advertisement. Commercial advertisements often seek to generate increased consumption of their products or services through "branding", which associates a product name or image with certain qualities in the minds of consumers. On the other hand, ads that intend to elicit an immediate sale are known as direct-response advertising. Non-commercial entities that advertise more than consumer products or services include political parties, interest groups, religious organizations and governmental agencies. Non-profit organizations may use free modes of persuasion, such as a public service announcement. Advertising may also help to reassure employees ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commercial Broadcasting
Commercial broadcasting (also called private broadcasting) is the broadcasting of television programs and radio programming by privately owned corporate media, as opposed to state sponsorship. It was the United States′ first model of radio (and later television) during the 1920s, in contrast with the public television model in Europe during the 1930s, 1940s and 1950s, which prevailed worldwide, except in the United States and Brazil, until the 1980s. Features Advertising Commercial broadcasting is primarily based on the practice of airing radio advertisements and television advertisements for profit. This is in contrast to public broadcasting, which receives government subsidies and usually does not have paid advertising interrupting the show. During pledge drives, some public broadcasters will interrupt shows to ask for donations. In the United States, non-commercial educational (NCE) television and radio exists in the form of community radio; however, premium cab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
