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Multi-Band Excitation
In telecommunications, a multi-band device (including (2) dual-band, (3) tri-band, (4) quad-band and (5) penta-band devices) is a communication device (especially a mobile phone) that supports multiple radio frequency bands. All devices which have more than one channel use multiple frequencies; a band however is a group of frequencies containing many channels. Multiple bands in mobile devices support roaming between different regions where different standards are used for mobile telephone services. Where the bands are widely separated in frequency, parallel transmit and receive signal path circuits must be provided, which increases the cost, complexity and power demand of multi-band devices. The term quad-band describes a device that supports four frequency bands: the 850 and 1900 MHz bands, which are used in the Americas, and 900 / 1800, which are used in most other parts of the world. Most GSM/ UMTS phones support all four bands, while most CDMA2000/1xRTT phones (mostly Nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola Timeport L7089
Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011. Motorola Solutions is the legal successor to Motorola, Inc., as the reorganization was structured with Motorola Mobility being spun off. Motorola Mobility was acquired by Lenovo in 2014. Motorola designed and sold wireless network equipment such as cellular transmission base stations and signal amplifiers. Motorola's home and broadcast network products included set-top boxes, digital video recorders, and network equipment used to enable video broadcasting, computer telephony, and high-definition television. Its business and government customers consisted mainly of wireless voice and broadband systems (used to build private networks), and, public safety communications systems like Astro an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attenuation
In physics, attenuation (in some contexts, extinction) is the gradual loss of flux intensity through a medium. For instance, dark glasses attenuate sunlight, lead attenuates X-rays, and water and air attenuate both light and sound at variable attenuation rates. Hearing protectors help reduce acoustic flux from flowing into the ears. This phenomenon is called acoustic attenuation and is measured in decibels (dBs). In electrical engineering and telecommunications, attenuation affects the propagation of waves and signals in electrical circuits, in optical fibers, and in air. Electrical attenuators and optical attenuators are commonly manufactured components in this field. Background In many cases, attenuation is an exponential function of the path length through the medium. In optics and in chemical spectroscopy, this is known as the Beer–Lambert law. In engineering, attenuation is usually measured in units of decibels per unit length of medium (dB/cm, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GSM Frequency Bands
GSM frequency bands or frequency ranges are the cellular frequencies designated by the ITU for the operation of GSM mobile phones and other mobile devices. Frequency bands GSM frequency usage around the world A dual-band 900/1800 device is required to be compatible with most networks apart from deployments in ITU Region 2. GSM-900, EGSM/EGSM-900 and GSM-1800 GSM-900 and GSM-1800 are used in most parts of the world (ITU-Regions 1 and 3): Africa, Europe, Middle East, Asia (apart from Japan and South Korea where GSM has never been introduced) and Oceania. In common GSM-900 is most widely used. Fewer operators use GSM-1800. Mobile Communication Services on Aircraft (MCA) uses GSM-1800. In some countries GSM-1800 is also referred to as "Digital Cellular System" (DCS). GSM-850 and GSM-1900 GSM-1900 and GSM-850 are used in most of North, South and Central America (ITU-Region 2). In North America, GSM operates on the primary mobile communication bands 850 MHz and 190 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of UMTS Networks
A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organizations * List College, an undergraduate division of the Jewish Theological Seminary of America * SC Germania List, German rugby union club Other uses * Angle of list, the leaning to either port or starboard of a ship * List (information), an ordered collection of pieces of information ** List (abstract data type), a method to organize data in computer science * List on Sylt, previously called List, the northernmost village in Germany, on the island of Sylt * ''List'', an alternative term for ''roll'' in flight dynamics * To ''list'' a building, etc., in the UK it means to designate it a listed building that may not be altered without permission * Lists (jousting), the barriers used to designate the tournament area where medieval knights jousted * ''The Book of Lists'', an American series of books with unusual lists See also * The List (other) * Listing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-Mobile US
T-Mobile US, Inc. is an American wireless network operator headquartered in Overland Park, Kansas and Bellevue, Washington, U.S. Its largest shareholder is a multinational telecommunications company Deutsche Telekom AG, which , holds 48.4 percent of the common stock. T-Mobile US is the second-largest wireless carrier in the United States, with more than 110 million subscribers . The company was founded in 1994 as VoiceStream Wireless before Deutsche Telekom purchased it in 2001 and renamed it after its T-Mobile brand. T-Mobile US provides wireless voice and data services in the United States under the T-Mobile and Metro by T-Mobile brands (the latter was acquired via the purchase of MetroPCS in a reverse takeover in 2013, resulting in T-Mobile going public on the NASDAQ stock exchange), and also serves as the host network for many mobile virtual network operators. The company has annual revenues of over $40 billion. In 2015, ''Consumer Reports'' named T-Mobile the number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectrum Repacking
A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism. As scientific understanding of light advanced, it came to apply to the entire electromagnetic spectrum. It thereby became a mapping of a range of magnitudes (wavelengths) to a range of qualities, which are the perceived "colors of the rainbow" and other properties which correspond to wavelengths that lie outside of the visible light spectrum. Spectrum has since been applied by analogy to topics outside optics. Thus, one might talk about the " spectrum of political opinion", or the "spectrum of activity" of a drug, or the "autism spectrum". In these uses, values within a spectrum may not be associated with precisely quantifiable numbers or definitions. Such uses imply a broad range of conditi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adjacent-channel Interference
Adjacent-channel interference (ACI) is interference caused by extraneous power from a signal in an adjacent channel. ACI may be caused by inadequate filtering (such as incomplete filtering of unwanted modulation products in FM systems), improper tuning or poor frequency control (in the reference channel, the interfering channel or both). ACI is distinguished from crosstalk.Federal Standard 1037Accessed: 2011-10-19. (Archived by WebCite at http://webcitation.org/62Z8qe0pC)/ref> Origin The adjacent-channel interference which receiver A experiences from a transmitter B is the sum of the power that B emits into A's channel—known as the "unwanted emission", and represented by the ACLR (Adjacent Channel Leakage Ratio)—and the power that A picks up from B's channel, which is represented by the ACS (Adjacent Channel Selectivity). B emitting power into A's channel is called adjacent-channel leakage (unwanted emissions). It occurs for two reasons. First, because RF filters require ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verizon Wireless
Verizon is an American wireless network operator that previously operated as a separate division of Verizon Communications under the name Verizon Wireless. In a 2019 reorganization, Verizon moved the wireless products and services into the divisions Verizon Consumer and Verizon Business, and stopped using the Verizon Wireless name. Verizon is the largest wireless carrier in the United States, with 142.8 million subscribers at the end of Q4 2021. The company is headquartered in Basking Ridge, New Jersey. It was founded in 2000 as a joint venture of American telecommunications firm Bell Atlantic, which would soon become Verizon Communications, and British multinational telecommunications company Vodafone. Verizon Communications became the sole owner in 2014 after buying Vodafone's 45-percent stake in the company. It operates a national 4G LTE network covering about 99 percent of the U.S. population, which in the second half of 2020 won or tied for top honors in each ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northeast Corridor
The Northeast Corridor (NEC) is an electrified railroad line in the Northeast megalopolis of the United States. Owned primarily by Amtrak, it runs from Boston through Providence, New Haven, Stamford, New York City, Philadelphia, Wilmington, and Baltimore to Washington, D.C. The NEC closely parallels Interstate 95 for most of its length, and is the busiest passenger rail line in the United States both by ridership and by service frequency as of 2013. The NEC carries more than 2,200 trains daily. The corridor is used by many Amtrak trains, including the high-speed Acela, intercity trains and several long-distance trains. Most of the corridor also has frequent commuter rail service, operated by the MBTA, Shore Line East, Hartford Line, Metro-North Railroad, Long Island Rail Road, New Jersey Transit, SEPTA and MARC. While large through freights have not run on the NEC since the early 1980s, several companies continue to run smaller local freights over some select few sec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the most populated subnational entity in North America and the 34th most populous in the world. The Greater Los Angeles area and the San Francisco Bay Area are the nation's second and fifth most populous urban regions respectively, with the former having more than 18.7million residents and the latter having over 9.6million. Sacramento is the state's capital, while Los Angeles is the most populous city in the state and the second most populous city in the country. San Francisco is the second most densely populated major city in the country. Los Angeles County is the country's most populous, while San Bernardino County is the largest county by area in the country. California borders Oregon to the north, Nevada and Arizona to the east, the M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pay TV
Pay television, also known as subscription television, premium television or, when referring to an individual service, a premium channel, refers to subscription-based television services, usually provided by multichannel television providers, but also increasingly via digital terrestrial, and streaming television. In the United States, subscription television began in the late 1970s and early 1980s in the form of encrypted analog over-the-air broadcast television which could be decrypted with special equipment. The concept rapidly expanded through the multi-channel transition and into the post-network era. Other parts of the world beyond the United States, such as France and Latin America have also offered encrypted analog terrestrial signals available for subscription. The term is most synonymous with premium entertainment services focused on films or general entertainment programming such as, in the United States, Cinemax, Epix, HBO, Showtime, and Starz, but such services ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MediaFLO
MediaFLO was a technology developed by Qualcomm for transmitting audio, video and data to portable devices such as mobile phones and personal televisions, used for mobile television. In the United States, the service powered by this technology was branded as FLO TV. Broadcast data transmitted via MediaFLO includes live, real time audio and video streams, as well as scheduled video and audio clips and shows. The technology could also carry Internet Protocol datacast application data, such as stock market quotes, sports scores, and weather reports. In October 2010, Qualcomm announced it was suspending new sales of the service to consumers. In December 2010, AT&T announced that it will purchase Qualcomm's FCC licenses in the 700 MHz band. FLO TV discontinued service on March 27, 2011. Overview The "FLO" in MediaFLO stood for ''Forward Link Only'', meaning that the data transmission path is one way, from the tower to the device. The MediaFLO system transmitted data on a freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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