In recent years, cellular voice networks have transformed into powerful packet-switched access networks for both voice communication and Internet access. Evolving Universal Mobile Telecommunication System (UMTS) networks and first Long Term Evolution (LTE) installations now deliver bandwidths of several megabits per second to individual users, and mobile access to the Internet from handheld devices and notebooks is no longer perceived as slower than a Digital Subscriber Line (DSL) or cable connection. Bandwidth and capacity demands, however, keep rising because of the increasing number of people using the networks and because of bandwidth-intensive applications such as video streaming. Thus, network manufacturers and network operators need to find ways to continuously increase the capacity and performance of their cellular networks while reducing the cost.
标签： BRINGING NETWORKS Beyond and 3G 4G
上传时间： 2020-05-26
上传用户：shancjb
Fordecades,microwavelineofsight(LOS)linkshavebeenoneofthebasictechnolo- gies used to build telephone networks. Until 1980, the fast rollout of high capacity transport networks and deployment of links in areas with challenging geographic characteristics could not be understood without this technology.
上传时间： 2020-05-28
上传用户：shancjb
One of the very first books published on the social impact of the mobile phone was Timo Kopomaa’s The City in Your Pocket: Birth of the Mobile Information Society. The book, published in 2000, was based on research that Kopomaa had under- taken for Nokia and Sonera as part of his doctoral studies in the Centre for Urban and Regional Studies at the Helsinki University of Technology. The first line he writes in the book is peculiar: ‘Mobile communication is not a serious matter’. By this, we assume he is referring to a view of the world that would regard the mobile phone as little more than an unremarkable fact of everyday life – a simple play- thing for the young, or a productivity tool for the business executive and busy parent.
标签： Communications Wireless Mobile and
上传时间： 2020-05-30
上传用户：shancjb
his research aims at creating broadband tunable, fully integrated filters for the application of cognitive radio and signal classification receivers. The approach under study is the N-path filter technique which is capable of translating a baseband impedance to a reference frequency creating a tunable filter. The traditional N-path filter suffers from fundamental architectural limitations, namely : a trade-off between insertion loss and out-of-band rejection, reference clock feed- through, and jammer power handling limitations. In the first approach, the fundamental trade- off of the traditional N-path filter between insertion loss and out-of-band rejection is improved by a transmission line (T-line) N-path filter technique.
上传时间： 2020-05-31
上传用户：shancjb
Rapid progress in information and communications technology (ICT) induces improved and new telecommunications services and contributes greatly to society in general and to vendors and network and service providers. In addition to existing services such as telephony or leased line services, spread of the Internet, the Internet Protocol (IP) phone, and new communications services like IPTV are making great progress with the development of digital subscriber lines (DSL) and high - speed communications technologies like fi ber to the home (FTTH).
标签： Telecommunications Networks
上传时间： 2020-06-01
上传用户：shancjb
Welcome to the world of wireless communications and the logical extension to the broadband architectures that are emerging as the future of the industry. No aspect of communications will be untouched by the wireless interfaces;no part of our working environment will be left untouched either. As the world changes and the newer technologies emerge, we can expect to see more in the line of untethered communications than in the wired inter- faces.
标签： Broadband Wireless Handbook
上传时间： 2020-06-01
上传用户：shancjb
The “bottom-line” metrics of cash flow, demand, price, and return on investment are driven by a second set of financial metrics represented by value to the customer, cost, and the pace of innovation. Get them right relative to competition and impressive bottom-line results should follow. Because of their importance, we call value to the customer, variable cost, and the pace of innovation the “fundamental metrics.”
标签： Planning Product Systems Driven Value and
上传时间： 2020-06-06
上传用户：shancjb
Modern power systems involve large amount of investment. An electric power system comprises of generation, transmission, and distribution of electric energy. Growth of power systems has led to very complex networks extended across large areas. In such situations, the proper functioning of a modern power system is heavily dependent upon the healthy operation of the transmission lines within it. Transmission lines are used to transmit a huge amount of power over a long distance. But as these lines are located in the open atmosphere, they are highly affected by different types of abnormal conditions or faults.
标签： Transmission Protection Line
上传时间： 2020-06-07
上传用户：shancjb
Phenomenon is an overused and overloaded term, but somehow it seems appropriate for Arduino—an endeavor that has caught the attention of an astonishingly wide range of people and provided opportunities for those who might otherwise have never picked up a soldering iron or written a single line of code. From dyed-in-the-wool hardware hackers to web page developers, robotics enthusiasts to installation artists, textile students to musicians: all can be found in the Arduino community. The versatility of the platform encompassing both hardware and software, combined with its inherent openness, has captured the imagination of tens of thousands of developers.
标签： Practical Projects Arduino Cool
上传时间： 2020-06-09
上传用户：shancjb
This design uses Common-Emitter Amplifier (Class A) with 2N3904 Bipolar Junction Transistor. Use “Voltage Divider Biasing” to reduce the effects of varying β (= ic / ib) (by holding the Base voltage constant) Base Voltage (Vb) = Vcc * [R2 / (R1 + R2)] Use Coupling Capacitors to separate the AC signals from the DC biasing voltage (which only pass AC signals and block any DC component). Use Bypass Capacitor to maintain the Q-point stability. To determine the value of each component, first set Q-point close to the center position of the load line. (RL is the resistance of the speaker.)
上传时间： 2020-11-27
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