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Digital Audio Broadcasting
Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services. Types In digital broadcasting systems, the analog audio signal is digitized, compressed using an audio coding format such as AAC+ ( MDCT) or MP2, and transmitted using a digital modulation scheme. The aim is to increase the number of radio programs in a given spectrum, to improve the audio quality, to eliminate fading problems in mobile environments, to allow additional datacasting services, and to decrease the transmission power or the number of transmitters required to cover a region. However, analog radio (AM and FM) is still more popular and listening to radio over IP ( Internet Protocol) is growing in popularity. In 2012 four digital wireless radio systems are recognized by the International Telecommunication Union: the two European systems Digital Audio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Spectrum
The radio spectrum is the part of the electromagnetic spectrum with frequencies from 0 Hz to 3,000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU). Different parts of the radio spectrum are allocated by the ITU for different radio transmission technologies and applications; some 40 radiocommunication services are defined in the ITU's Radio Regulations (RR). In some cases, parts of the radio spectrum are sold or licensed to operators of private radio transmission services (for example, cellular telephone operators or broadcast television stations). Ranges of allocated frequencies are often referred to by their provisioned use (for exa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Radio Mondiale
Digital Radio Mondiale (DRM; ''mondiale'' being Italian and French for "worldwide") is a set of digital audio broadcasting technologies designed to work over the bands currently used for analogue radio broadcasting including AM broadcasting—particularly shortwave—and FM broadcasting. DRM is more spectrally efficient than AM and FM, allowing more stations, at higher quality, into a given amount of bandwidth, using xHE-AAC audio coding format. Various other MPEG-4 and Opus codecs are also compatible, but the standard now specifies xHE-AAC. Digital Radio Mondiale is also the name of the international non-profit consortium that has designed the platform and is now promoting its introduction. Radio France Internationale, TéléDiffusion de France, BBC World Service, Deutsche Welle, Voice of America, Telefunken (now Transradio) and Thomcast (now Ampegon) took part at the formation of the DRM consortium. The principle of DRM is that bandwidth is the limiting factor, and com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dedicated Short-range Communications
Dedicated short-range communications (DSRC) are one-way or two-way short-range to medium-range wireless communication channels specifically designed for automotive use and a corresponding set of protocols and standards. History In October 1999, the United States Federal Communications Commission (FCC) allocated 75 MHz of spectrum in the 5.9 GHz band to be used by intelligent transportation systems (ITS). In August 2008, the European Telecommunications Standards Institute (ETSI) allocated 30 MHz of spectrum in the 5.9 GHz band for ITS. By 2003, it was used in Europe and Japan in electronic toll collection. DSRC systems in Europe, Japan and the U.S. are not compatible and include some very significant variations (5.8 GHz, 5.9 GHz or even infrared, different baud rates, and different protocols). Singapore's Electronic Road Pricing scheme plans to use DSRC technology for road use measurement (ERP2) to replace its ERP1 overhead gantry method. In June ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-way Digital Radio Standards
Two-way or Two Way may refer to: * " 2-Way", single by rapper Lil' Romeo * Two-way, Cincinnati chili topped on spaghetti * "Two Way" (KT Tunstall and James Bay duet), 2016 See also * * * * 3-Way (other) {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital TV
Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio (commonly 16:9) in contrast to the narrower format of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more wide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Signal (electronics)
A digital signal is a signal that represents data as a sequence of discrete values; at any given time it can only take on, at most, one of a finite number of values. This contrasts with an analog signal, which represents continuous values; at any given time it represents a real number within a continuous range of values. Simple digital signals represent information in discrete bands of analog levels. All levels within a band of values represent the same information state. In most digital circuits, the signal can have two possible valid values; this is called a binary signal or logic signal. They are represented by two voltage bands: one near a reference value (typically termed as ''ground'' or zero volts), and the other a value near the supply voltage. These correspond to the two values "zero" and "one" (or "false" and "true") of the Boolean domain, so at any given time a binary signal represents one binary digit (bit). Because of this discretization, relatively small chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Information
Information is an abstract concept that refers to that which has the power to inform. At the most fundamental level information pertains to the interpretation of that which may be sensed. Any natural process that is not completely random, and any observable pattern in any medium can be said to convey some amount of information. Whereas digital signals and other data use discrete signs to convey information, other phenomena and artifacts such as analog signals, poems, pictures, music or other sounds, and currents convey information in a more continuous form. Information is not knowledge itself, but the meaning that may be derived from a representation through interpretation. Information is often processed iteratively: Data available at one step are processed into information to be interpreted and processed at the next step. For example, in written text each symbol or letter conveys information relevant to the word it is part of, each word conveys information ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Communications
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraft ... [...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 frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and 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 SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations. The prefix ' in ''microwave'' is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small" (having shorter wavelengths), compared to the radio waves used prior to microwave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Transmission
Data transmission and data reception or, more broadly, data communication or digital communications is the transfer and reception of data in the form of a digital bitstream or a digitized analog signal transmitted over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication using radio spectrum, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal. Analog transmission is a method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. The messages are either represented by a sequence of pulses by means of a line code (''baseband transmission''), or by a limited set of continuously varying waveforms ('' passband transmission''), using a digital modulati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wireless
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most common wireless technologies use radio waves. With radio waves, intended distances can be short, such as a few meters for Bluetooth or as far as millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of applications of radio ''wireless technology'' include GPS units, garage door openers, wireless computer mouse, keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones. Somewhat less common methods of achieving wireless communications involve other electromagnetic phen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD Radio
HD Radio (HDR) is a trademark for an in-band on-channel (IBOC) digital radio broadcast technology. It generally simulcasts an existing analog radio station in digital format with less noise and with additional text information. HD Radio is used primarily by AM and FM radio stations in the United States, Canada, and Mexico, with a few implementations outside North America. The term "on channel" is a misnomer because the system actually broadcasts on the ordinarily unused channels adjacent to an existing radio station's allocation. This leaves the original analog signal intact, allowing enabled receivers to switch between digital and analog as required. In most FM implementations, from 96 to 128 kbps of capacity is available. High-fidelity audio requires only 48 kbps so there is ample capacity for additional channels, which HD Radio refers to as "multicasting". HD Radio is licensed so that the simulcast of the main channel is royalty-free. The company makes its money ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
