The unguided Transmission of information using electromagnetic waves at radio frequency (RF) is often referred to as wireless communications, the first demonstration of which took place at the end of the 19th cen- tury and is attributed to Hertz. The technology was, shortly thereafter, commercialised by, amongst others, Marconi in one of the first wire- less communication systems, i.e., wireless telegraphy. In the first half of the 20th century the technology was developed further to enable more than the mere Transmission of Morse code. This first resulted in uni- directional radio broadcasting and several years later also in television broadcasting.
标签： Imperfections RF
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The market for cellular phones and wireless data Transmission equipment has changed dramatically since the late 1970s when cellular phones were first introduced and the late 1980s when wireless data equipment became available. As would be expected, duringthistime RF test requirements and RF test equipment has changed dramatically.
标签： Measurements Cellular Phones for RF
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Wireless communication has become increasingly important not only for professional appli- cations but also for many fields in our daily routine and in consumer electronics. In 1990, a mobile telephone was still quite expensive, whereas today most teenagers have one, and they use it not only for calls but also for data Transmission. More and more computers use wireless local area networks (WLANs), and audio and television broadcasting has become digital.
标签： Applications and Theory OFDM CDMA of
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Fourth Generation (4G) wireless communication systems aim to allow peak data rates in the range of 1 Gbps for nomadic access and 100 Mbps for vehicular mobil- ity. 4G aims to support current and emergent multimedia services, such as mobile TV, social networks and gaming, high-definition television and video telecon- ference, multimedia messaging service, using the All-over IP concept and with improved quality of service.
标签： Transmission Techniques Systems for 4G
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Public telephone operators and new independent wireless operators through- out the world are deploying wireless access in an effort to drastically reduce delivery costs in the most expensive part of the network?the local loop. Available radio technology enables both existing and new entrants to access subscribers in a rapid manner and deliver their basic telephony products and broadband-enhanced services.
标签： Transmission Handbooks Systems Design
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An acronym for Multiple-In, Multiple-Out, MIMO communication sends the same data as several signals simultaneously through multiple antennas, while still utilizing a single radio channel. This is a form of antenna diversity, which uses multiple antennas to improve signal quality and strength of an RF link. The data is split into multiple data streams at the Transmission point and recombined on the receive side by another MIMO radio configured with the same number of antennas. The receiver is designed to take into account the slight time difference between receptions of each signal, any additional noise or interference, and even lost signals.
标签： Understanding_the_Basics_of_MIMO
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Wavelength division multiplexing (WDM) refers to a multiplexing and Transmission scheme in optical telecommunications fibers where different wavelengths, typically emitted by several lasers, are modulated independently (i.e., they carry independent information from the transmitters to the receivers). These wavelengths are then multiplexed in the transmitter by means of passive WDM filters, and likewise they are separated or demultiplexed in the receiver by means of the same filters or coherent detection that usually involves a tunable local oscillator (laser).
标签： Multiplexing Wavelength Division
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Digital radios have undergone an astonishing evolution in the last century. Born as a set of simple and power-hungry electrical and electromechanical devices for low data rate Transmission of telegraph data in the Marconi age, they have transformed, thanks to substantial advances in electronic technology, into a set of small, reliable and sophisticated integrated devices supporting broadband multimedia communications. This, however, would not have been possible unless significant progress had been made in recent decades in the field of signal processing algorithms for baseband and passband signals. In fact, the core of any modern digital radio consists of a set of algorithms running over programmable electronic hardware. This book stems from the research and teaching activities of its co-authors in the field of algorithmic techniques for wireless communications. A huge body of technical literature has accumulated in the last four decades in this area, and an extensive coverage of all its important aspects in a single textbook is impossible. For this reason, we have selected a few important topics and, for ease of reading, organized them into two parts.
标签： Communications Algorithmic Techniques Wireless
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For more than a century, overhead lines have been the most commonly used technology for transmitting electrical energy at all voltage levels, especially on the highest levels. However, in recent years, an increase in both the number and length of HVAC cables in the Transmission networks of different countries like Denmark, Japan or United Kingdom has been observed. At the same time, the construction of offshore wind farms, which are typically connected to the shore through HVAC cables, increased exponentially.
标签： Electromagnetic Transients Cables Power in
上传时间： 2020-06-07
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The solid high-polymer-film-type fuel cell (PEM-FC) system is used as the power supply equipment for transportation and replaces an internal combustion engine. A reduction of the environmental load is expected through the cogeneration system’s (CGS) use of the PEM-FC system as a distributed power supply to individual houses, apartments, and so forth [1–3]. The growing use of distributed power systems, such as fuel cells, the reduction of power-Transmission losses, and an increase of waste heat recovery are expected. Therefore, the reduction of carbon- dioxide emission is also expected as compared to conventional energy supply methods using commercial electric power.
标签： Micro-grids Fuel Cell
上传时间： 2020-06-07
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