The first practical examples of mobile communications were used in many countries like the USA, the UK and Germany in military services, and played a significant role in the First World War to transfer important information from the front to headquarters to take further actions. Good and secure wireless communications were an important need for all military services – army, navy and air force. In this respect, the Second World War was a big experimental battlefield for the development and evolution of mobile radio. It was in the interests of governments that after the Second World War the military investment should be paid back by civilian use, and all western European countries started their so-called first generation of mobile communication networks.
標(biāo)簽： Multimedia Business Mobile The
上傳時間： 2020-06-01
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Changes in telecommunications are impacting all types of user group, which include business users, traveling users, small and home offices, and residential users. The acceptance rate of telecom- munications and information services is accelerating significantly. Voice services needed approximately 50 years to reach a very high teledensity; television needed just 15 years to change the culture and lives of many families; the Internet and its related services have been penetrating and changing business practices and private com- munications over the last 2 to 3 years.
標(biāo)簽： Telecommunications Handbook The
上傳時間： 2020-06-01
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The continuing explosive growth in mobile communication is demanding more spectrally efficient radio access technologies than the prevalent second generation (2G) systems such as GSM to handle just the voice traffic. We are already witnessing high levels of mobile penetration exceeding 70% in some countries. It is anticipated that by 2010 more than half of all communications will be carried out by mobile cellular networks. On the other hand, the information revolution and changing life habits are bringing the requirement of commu- nicating on a multimedia level to the mobile environment. But the data handling capabilities and flexibility of the 2G cellular systems are limited.
標(biāo)簽： Planning Network UMTS
上傳時間： 2020-06-01
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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.
標(biāo)簽： Understanding_the_Basics_of_MIMO
上傳時間： 2020-06-01
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In the seven years since the first edition of this book was completed, Electrostatic Discharge (ESD) phenomena in integrated circuits (IC) continues to be important as technologies shrink and the speed and size of the chips increases. The phenom- ena related to ESD events in semiconductor devices take place outside the realm of normal device operation. Hence, the physics governing this behavior are not typ- ically found in general textbooks on semiconductors.
標(biāo)簽： Integrated Circuits Silicon ESD In
上傳時間： 2020-06-05
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Electrostatic discharge (ESD) events can have serious detrimental effects on the manufacture and performance of microelectronic devices, the systems that contain them, and the manufacturing facilities used to produce them. Submicron device technologies, high system operating speeds, and factory automation are making ESD control programs a critical factor in the quality and reliability of ESD-sensitive products.
標(biāo)簽： Management Program ESD
上傳時間： 2020-06-05
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ESD is a crucial factor for integrated circuits and influences their quality and reliability. Today increasingly sensitive processes with deep sub micron structures are developed. The integration of more and more functionality on a single chip and saving of chip area is required. Integrated circuits become more susceptible to ESD/EOS related damages. However, the requirements on ESD robustness especially for automotive applications are increasing. ESD failures are very often the reason for redesigns. Much research has been conducted by semiconductor manufacturers on ESD robust design.
標(biāo)簽： Guidelines Design Basic ESD
上傳時間： 2020-06-05
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The planarization technology of Chemical-Mechanical-Polishing (CMP), used for the manufacturing of multi- level metal interconnects for high-density Integrated Circuits (IC), is also readily adaptable as an enabling technology in MicroElectroMechanical Systems (MEMS) fabrication, particularly polysilicon surface micromachining. CMP not only eases the design and manufacturability of MEMS devices by eliminating several photolithographic and film issues generated by severe topography, but also enables far greater flexibility with process complexity and associated designs. T
標(biāo)簽： mechanical polishing Chemical
上傳時間： 2020-06-06
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Thanks to the advances in micromachining fabrication technologies and significant cost reduction due to mass production, miniature sensors of angular rate, or gyroscopes, found their way into the everyday life of every user of modern gadgets, such as smart phones, tablets or even wristwatches. Often without realising, many of us are carrying in our pockets fully equipped with all necessary sensors complete inertial navigation systems that not so long ago were available only for advanced vehicles in sea, land, air or space. Accelerometers and gyroscopes are found in specifications of any gadget supposed to react to user movements. And one of the most commonly used type of gyroscopes used to developed these systems is Coriolis vibratory gyroscope (CVG).
標(biāo)簽： Gyroscopes Vibratory Coriolis
上傳時間： 2020-06-06
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This book is written for engineers involved in the operation, control, and planning of electric power systems. In addition, the book provides information and tools for researchers working in the fields of power system security and stability. The book consists of two volumes. The first volume provides traditional techniques for the stability analysis of large scale power systems. In addition, an overview of the main drivers and requirements for modernization of the traditional methods for online applications are discussed. The second volume provides techniques for online security assessment and corrective action studies. In addition, the impact of variable generation on the security of power systems is considered in the second volume. The first volume may be considered as a background builder while the second volume is intended for the coverage of edge techniques and methods for online dynamic security studies.
上傳時間： 2020-06-07
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