This program can determin very accurately the nature of the user input
標(biāo)簽： accurately the determin program
上傳時間： 2015-01-28
上傳用戶：shinesyh
nature上的經(jīng)典文章，被引次數(shù)俞2000次，揭示廣泛的small-world共有的動態(tài)機制
標(biāo)簽： nature
上傳時間： 2014-01-18
上傳用戶：葉山豪
learning English The following appeared in a memorandum written by the vice president of nature s Way, a chain of stores selling health food and other health-related products. "Previous experience has shown that our stores are most profitable in areas where residents are highly concerned with leading healthy lives. We should therefore build our next new store in Plainsville, which has many such residents. Plainsville merchants report that sales of running shoes and exercise clothing are at all-time highs. The local health club, which nearly closed five years ago due to lack of business, has more members than ever, and the weight training and aerobics classes are always full. We can even anticipate a new generation of customers: Plainsville s schoolchildren are required to participate in a fitness for life program, which emphasizes the benefits of regular exercise at an early age.
標(biāo)簽： memorandum following president learning
上傳時間： 2017-03-06
上傳用戶：youth25
Despite its highly adaptable and flexible nature, C++ is also one of the more complex programming languages to learn. Once mastered, however, it can help you organize and process information with amazing efficiency and quickness.
標(biāo)簽： programming adaptable flexible Despite
上傳時間： 2013-12-31
上傳用戶：zhyiroy
自上個世紀九十年代以來，我國著名學(xué)者、現(xiàn)中國科學(xué)院院士、清華大學(xué)陳難先教授等人使用無窮級數(shù)的Mobius反演公式解決了一系列重要的應(yīng)用物理中的逆問題，例如費米體系逆問題、信號處理等，開創(chuàng)了應(yīng)用、推廣數(shù)論中的Mobius變換解決物理學(xué)中各種逆問題的巧妙方法，其工作在1990年得到了世界著名的《nature》雜志的整版專評與高度評價。華僑大學(xué)蘇武潯、張渭濱教授等則把Mobius變換的方法應(yīng)用于幾種常用波形（包括周期矩形脈沖，奇偶對稱方波和三角波等）的傅立葉級數(shù)的逆變換運算，得到正、余弦函數(shù)及一般周期信號的各種常用波形的信號展開；并求得了與各種常用波形信號函數(shù)族相正交的函數(shù)族，以用于各展開系數(shù)的計算與信息的解調(diào)；而后把它們應(yīng)用到通信系統(tǒng)中，提出了一種新的通信系統(tǒng)，即新型Chen-Mobius通信系統(tǒng)。 在新型通信系統(tǒng)中，把這種正交函數(shù)族應(yīng)用于系統(tǒng)的相干調(diào)制解調(diào)中，取代傳統(tǒng)通信系統(tǒng)中調(diào)制解調(diào)所采用的三角正交函數(shù)族。正是這種正交函數(shù)族使得通信系統(tǒng)的傳輸性能大大提高，保密性加強，而且正交函數(shù)族產(chǎn)生很方便。 本文從軟件仿真和硬件實現(xiàn)兩個方面對Chen-Mobius通信系統(tǒng)進行了驗證。首先，利用MATLAB軟件構(gòu)建Chen-Mobius數(shù)字通信系統(tǒng)，通過計算機編程，對Chen-Mobius單路、四路和八路的數(shù)字通信系統(tǒng)進行仿真分析，對該系統(tǒng)在不同信噪比情況下的錯誤概率進行了計算，并繪出了信噪比-錯誤概率曲線；其次，在QuartusⅡ軟件平臺上，利用VHDL語言文本輸入和原理圖輸入的方法構(gòu)建Chen-Mobius數(shù)字通信系統(tǒng)，對該系統(tǒng)進行了仿真，包括設(shè)計綜合、引腳分配、仿真驗證、時序分析等；再次，在QuartusⅡ軟件仿真的基礎(chǔ)上，在Altera公司的Stratix GX芯片上，實現(xiàn)了硬件的編程和下載，從而完成了Chen-Mobius數(shù)字通信系統(tǒng)的FPGA實現(xiàn)；最后，從MATLAB軟件仿真和硬件實現(xiàn)的結(jié)果出發(fā)，通過分析系統(tǒng)的性能，簡單展望了Chen-Mobius數(shù)字通信系統(tǒng)的應(yīng)用前景。 本文通過軟件仿真得到了Chen-Mobius數(shù)字通信系統(tǒng)的信噪比-錯誤概率曲線，從理論上驗證了該系統(tǒng)的強的抗干擾能力；利用FPGA完成了系統(tǒng)的硬件實現(xiàn)，從實際上驗證了該系統(tǒng)的可實現(xiàn)性。從兩方面都可以說明，Chen-Mobius通信系統(tǒng)雖然只是一個新的起點，但它卻預(yù)示著光明的應(yīng)用前景。
標(biāo)簽： ChenMobius MATLAB FPGA 數(shù)字通信系統(tǒng)
上傳時間： 2013-05-19
上傳用戶：sa123456
自上個世紀九十年代以來，我國著名學(xué)者、現(xiàn)中國科學(xué)院院士、清華大學(xué)陳難先教授等人使用無窮級數(shù)的Mobius反演公式解決了一系列重要的物理學(xué)中的逆問題，開創(chuàng)了應(yīng)用、推廣數(shù)論中的Mobius變換解決物理學(xué)中各種逆問題的巧妙方法，其工作在1990年當(dāng)時就得到了世界著名的《nature》雜志的高度評價。 華僑大學(xué)蘇武潯教授等則把Mobius變換的方法應(yīng)用于幾種常用波形(包括周期矩形脈沖，奇偶對稱方波和三角波等)的傅立葉級數(shù)的逆變換運算，得到正、余弦函數(shù)及一般周期信號的各種常用波形的信號展開；并求得了與各種常用波形信號函數(shù)族相正交的函數(shù)族，以用于各展開系數(shù)的計算與信息的解調(diào)；而后把它們應(yīng)用到通信系統(tǒng)中，提出了一種新的通信系統(tǒng)，即新型Chen-Mobius通信系統(tǒng)。 本文主要完成了兩個方面的工作,Chen-Mobius多路通信系統(tǒng)的FPGA硬件設(shè)計實現(xiàn)和基于Chen-Mobius變換的語音加密雙工通信系統(tǒng)的實現(xiàn)。首先，利用嵌入MATLAB\SIMULINK中的DSPBuilder軟件對Chen-Mobius多路(四路和八路)通信系統(tǒng)進行仿真分析，對該系統(tǒng)在不同信噪比情況下的錯誤概率進行了計算，并繪出了信噪比-錯誤概率曲線；其次，利用DSPBuilder中的Signalcompiler將Chen-Mobius多路通信系統(tǒng)的主體模塊(函數(shù)及積分器的產(chǎn)生等)轉(zhuǎn)化成HDL硬件語言，后在QuartusⅡ軟件平臺上，結(jié)合利用VHDL編程的硬件程序模塊(分頻、延時、控制模塊等)構(gòu)架完整的Chen-Mobius通信系統(tǒng)，并對此系統(tǒng)設(shè)計綜合、引腳分配、仿真驗證、時序分析等；最后，在Altera公司的Stratix 芯片上，實現(xiàn)硬件的編程和下載，從而完成了Chen-Mobius多路通信系統(tǒng)的FPGA硬件實現(xiàn)。 另外，利用Chen-Mobius單路通信系統(tǒng)的調(diào)制、解調(diào)系統(tǒng)分別對語音信號進行加密與解密，在兩塊DE2的FPGA開發(fā)板上成功實現(xiàn)了基于Chen-Mobius變換的語音加密雙工通信。完成本設(shè)計意義重大，它為今后Chen-Mobius通信系統(tǒng)應(yīng)用于通信領(lǐng)域的各個方面，邁開堅實的一步。
標(biāo)簽： ChenMobius FPGA 通信系統(tǒng) 硬件實現(xiàn)
上傳時間： 2013-07-24
上傳用戶：xaijhqx
Sensors for pressure, load, temperature, acceleration andmany other physical quantities often take the form of aWheatstone bridge. These sensors can be extremely linearand stable over time and temperature. However, mostthings in nature are only linear if you don’t bend them toomuch. In the case of a load cell, Hooke’s law states that thestrain in a material is proportional to the applied stress—as long as the stress is nowhere near the material’s yieldpoint (the “point of no return” where the material ispermanently deformed).
標(biāo)簽： Delta Sigma ADC 測量技術(shù)
上傳時間： 2013-11-13
上傳用戶：墻角有棵樹
高速數(shù)字系統(tǒng)設(shè)計下載pdf:High-Speed Digital SystemDesign—A Handbook ofInterconnect Theory and DesignPracticesStephen H. HallGarrett W. HallJames A. McCallA Wiley-Interscience Publication JOHN WILEY & SONS, INC.New York • Chichester • Weinheim • Brisbane • Singapore • TorontoCopyright © 2000 by John Wiley & Sons, Inc.speeddigital systems at the platform level. The book walks the reader through everyrequired concept, from basic transmission line theory to digital timing analysis, high-speedmeasurement techniques, as well as many other topics. In doing so, a unique balancebetween theory and practical applications is achieved that will allow the reader not only tounderstand the nature of the problem, but also provide practical guidance to the solution.The level of theoretical understanding is such that the reader will be equipped to see beyondthe immediate practical application and solve problems not contained within these pages.Much of the information in this book has not been needed in past digital designs but isabsolutely necessary today. Most of the information covered here is not covered in standardcollege curricula, at least not in its focus on digital design, which is arguably one of the mostsignificant industries in electrical engineering.The focus of this book is on the design of robust high-volume, high-speed digital productssuch as computer systems, with particular attention paid to computer busses. However, thetheory presented is applicable to any high-speed digital system. All of the techniquescovered in this book have been applied in industry to actual digital products that have beensuccessfully produced and sold in high volume.Practicing engineers and graduate and undergraduate students who have completed basicelectromagnetic or microwave design classes are equipped to fully comprehend the theorypresented in this book. At a practical level, however, basic circuit theory is all thebackground required to apply the formulas in this book.
標(biāo)簽： 高速數(shù)字 系統(tǒng)設(shè)計
上傳時間： 2013-10-26
上傳用戶：縹緲
Calculation of the Differential Impedance of Tracks on FR4 substrates There is a discrepancy between calculated and measured values of impedance for differential transmission lineson FR4. This is especially noticeable in the case of surface microstrip configurations. The anomaly is shown tobe due to the nature of the substrate material. This needs to be considered as a layered structure of epoxy resinand glass fibre. Calculations, using Boundary Element field methods, show that the distribution of the electricfield within this layered structure determines the apparent dielectric constant and therefore affects theimpedance. Thus FR4 cannot be considered to be uniform dielectric when calculating differential impedance.
上傳時間： 2014-12-24
上傳用戶：DE2542
為解決傳統(tǒng)可視倒車雷達視頻字符疊加器結(jié)構(gòu)復(fù)雜，可靠性差，成本高昂等問題，在可視倒車雷達設(shè)計中采用視頻字符發(fā)生器芯片MAX7456。該芯片集成了所有用于產(chǎn)生用戶定義OSD，并將其插入視頻信號中所需的全部功能，僅需少量的外圍阻容元件即可正常工作。給出了以MAX7456為核心的可視倒車雷達的軟、硬件實現(xiàn)方案及設(shè)計實例。該方案具有電路結(jié)構(gòu)簡單、價格低廉、符合人體視覺習(xí)慣的特點。經(jīng)實際裝車測試，按該方案設(shè)計的可視倒車雷達視場清晰、提示字符醒目、工作可靠，可有效降低駕駛員倒車時的工作強度、減少倒車事故的發(fā)生。 Abstract: A new video and text generation chip，MAX7456，was used in the design of video parking sensor in order to simplify system structure，improve reliability and reduce cost. This chip included all the necessary functions to generate user-defined OSDs and to add them into the video signals. It could be put into work with addition of just a small number of resistances and capacitors. This paper provided software and hardware implementation solutions and design example based on the chip. The system had the characteristics of simplicity in circuit structure，lower cost，and comfort for the nature of human vision. Loading road test demonstrates high video and text display quality and reliable performance，which makes the driver easy to see backward and reduces chance of accidents.
標(biāo)簽： 7456 MAX 可視倒車 中的應(yīng)用
上傳時間： 2013-12-10
上傳用戶：qiaoyue
蟲蟲下載站版權(quán)所有 京ICP備2021023401號-1
