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.
標(biāo)簽： Transmission Techniques Systems for 4G
上傳時(shí)間： 2020-06-01
上傳用戶(hù)：shancjb
Recent advances in wireless communication technologies have had a transforma- tive impact on society and have directly contributed to several economic and SOCIAL aspects of daily life. Increasingly, the untethered exchange of information between devices is becoming a prime requirement for further progress, which is placing an ever greater demand on wireless bandwidth. The ultra wideband (UWB) system marks a major milestone in this progress. Since 2002, when the FCC allowed the unlicensed use of low-power, UWB radio signals in the 3.1–10.6GHz frequency band, there has been significant synergistic advance in this technology at the cir- cuits, architectural and communication systems levels. This technology allows for devices to communicate wirelessly, while coexisting with other users by ensuring that its power density is sufficiently low so that it is perceived as noise to other users.
標(biāo)簽： Circuits Wideband Ultra
上傳時(shí)間： 2020-06-01
上傳用戶(hù)：shancjb
Five years have passed since the first edition of this book was published.Over the five years,the world has witnessed a technological revolution headlined by an array of exciting consumer and industrial products such as the Nintendo Wii, Apple iPod/iPad, sensor-rich smart phones, phones with cameras,new operating systems for mobile phones and apps,e-books,WiFi,voice- over-IP calls, SOCIAL networking, 3D animated movies, and cloud computing, to name the major ones that affect everyday living
標(biāo)簽： Foundations MEMS of
上傳時(shí)間： 2020-06-06
上傳用戶(hù)：shancjb
This is a practical book, to be sure, but it is also a book about hope and posi- tive change. I am quite sincere. The delivery of electricity is deeply rooted in the principle of universal access; when clean, reliable energy is available it contributes to poverty alleviation, improved SOCIAL conditions, and enhanced economic development. In the developed world, we know this to be true. The digital fabric of our lives is a testimony to the importance of energy security. Across the globe, we have seen the vital contributions that electrification has brought to the development of economies and an enhanced quality of life. Nonetheless, this supreme engineering achievement has languished, and we are deeply challenged.
標(biāo)簽： Strategies Analytics Data Big
上傳時(shí)間： 2020-06-07
上傳用戶(hù)：shancjb
Today, electric power transmission systems should face many demanding chal- lenges, which include balancing between reliability, economics, environmental, and other SOCIAL objectives to optimize the grid assets and satisfy the growing electrical demand. Moreover, the operational environment of transmission systems is becoming increasingly rigorous due to continually evolving functions of interconnected power networks from operation jurisdiction to control responsibly – coupled with the rising demand and expectation for reliability.
標(biāo)簽： Monitoring Protection Wide Area
上傳時(shí)間： 2020-06-07
上傳用戶(hù)：shancjb
Although doing science is at the heart of discovery, the effort would have very limited consequence in the long term without writingscience. As a SOCIAL enterprise that depends on collaboration, scientific inquiry requires its practi- tioners to write on a regular basis. From time to time, some members of the scientific community have been critical of the overall quality of writing by re- searchers.
標(biāo)簽： Goldbort_Writing Science for
上傳時(shí)間： 2020-06-09
上傳用戶(hù)：shancjb
Computer science as an academic discipline began in the 1960’s. Emphasis was on programming languages, compilers, operating systems, and the mathematical theory that supported these areas. Courses in theoretical computer science covered finite automata, regular expressions, context-free languages, and computability. In the 1970’s, the study of algorithms was added as an important component of theory. The emphasis was on making computers useful. Today, a fundamental change is taking place and the focus is more on a wealth of applications. There are many reasons for this change. The merging of computing and communications has played an important role. The enhanced ability to observe, collect, and store data in the natural sciences, in commerce, and in other fields calls for a change in our understanding of data and how to handle it in the modern setting. The emergence of the web and SOCIAL networks as central aspects of daily life presents both opportunities and challenges for theory.
標(biāo)簽： Foundations Science Data of
上傳時(shí)間： 2020-06-10
上傳用戶(hù)：shancjb
歷時(shí)四年，在繼好評(píng)如潮的《你好，放大器》之后，西安交通大學(xué)電氣工程學(xué)院楊建國(guó)老師攜模電系列叢書(shū)《新概念模擬電路》再度歸來(lái)！全書(shū)共五冊(cè)，近50萬(wàn)字，一樣的風(fēng)趣幽默，一樣的SOCIAL化語(yǔ)言，深入淺出地將枯燥深?yuàn)W的模電知識(shí)講得簡(jiǎn)單易學(xué)。《新概念模擬電路》叢書(shū)包含了《晶體管》、《負(fù)反饋和運(yùn)算放大器》、《運(yùn)放電路的頻率特性和濾波器》、《信號(hào)處理電路》以及《源電路·信號(hào)和電源》，絕大部分內(nèi)容都是楊教授親自實(shí)驗(yàn)或仿真總結(jié)之后才寫(xiě)出來(lái)的，非常有價(jià)值。楊教授表示，"盡管全書(shū)囊括眾多模電知識(shí)點(diǎn)，但它絕不會(huì)是一本有著欺世盜名名字卻包羅萬(wàn)象的大雜燴。"
標(biāo)簽： 模擬電路
上傳時(shí)間： 2022-03-22
上傳用戶(hù)：zhanglei193
溫度控制如今已成為當(dāng)代社會(huì)研究的熱點(diǎn)之一,而溫度檢測(cè)在現(xiàn)代設(shè)備參數(shù)檢測(cè)中也是一項(xiàng)極其重要的技術(shù),應(yīng)用十分廣泛。與傳統(tǒng)的測(cè)溫方法相比,紅外測(cè)溫方法具有時(shí)間短、精度高、使用簡(jiǎn)單方便等優(yōu)點(diǎn)。本文以環(huán)境溫度為被測(cè)對(duì)象,設(shè)計(jì)了以STC89C52單片機(jī)為控制中心的紅外測(cè)溫裝置,能夠?qū)崿F(xiàn)對(duì)目標(biāo)溫度的實(shí)時(shí)采集、處理、顯示和報(bào)警等功能。本設(shè)計(jì)主要是由STC89C52單片機(jī)、紅外測(cè)溫傳感器、LCD1602液晶顯示器、按鍵和蜂鳴器等部分組成,采用非接觸的方式對(duì)目標(biāo)溫度進(jìn)行實(shí)時(shí)檢測(cè)。Temperature control has become one of the hotspots in contemporary SOCIAL research,and temperature detection is an extremely important technology in modern equipment parameter detection.Compared with traditional method,the infrared temperature measuring method has advantages of short time,high precision and convenient operation,etc.This paper consider environment temperature as research objects and designs an infrared temperature measuring device which employs the STC89C52singlechipas-control center,and it can realize timely collection,processing,display and alarm function of the target temperature.The design is mainly composed of STC89C52 singlechip,infrared temperature sensor,LCD1602monitor,keys and buzzer,etc.This design detects the target temperature by non-contact method.
上傳時(shí)間： 2022-03-27
上傳用戶(hù)：jiabin
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