Power conversion by virtue of its basic role produces harmonics due to theslicing of either voltages or currents. To a large extent the pollution in theutility supply and the deterioration of the power quality has been generatedor created by non-linear converters. It is therefore ironic that power convertersshould now be used to clean up the pollution that they helped to create inthe first place.In a utility system, it is desirable to prevent harmonic currents (which resultin EMI and resonance problems) and limit reactive power flows (whichresult in transmission losses).Traditionally, shunt passive filters, comprised of tuned LC elements andcapacitor banks, were used to filter the harmonics and to compensate forreactive current due to non-linear loads. However, in practical applicationsthese methods have many disadvantages.
上傳時間： 2013-11-05
上傳用戶：AISINI005
高速數字系統設計下載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.
上傳時間： 2013-10-26
上傳用戶：縹緲
This document provides practical, common guidelines for incorporating PCI Express interconnect layouts onto Printed Circuit Boards (PCB) ranging from 4-layer desktop baseboard designs to 10- layer or more server baseboard designs. Guidelines and constraints in this document are intended for use on both baseboard and add-in card PCB designs. This includes interconnects between PCI Express devices located on the same baseboard (chip-to-chip routing) and interconnects between a PCI Express device located “down” on the baseboard and a device located “up” on an add-in card attached through a connector. This document is intended to cover all major components of the physical interconnect including design guidelines for the PCB traces, vias and AC coupling capacitors, as well as add-in card edge-finger and connector considerations. The intent of the guidelines and examples is to help ensure that good high-speed signal design practices are used and that the timing/jitter and loss/attenuation budgets can also be met from end-to-end across the PCI Express interconnect. However, while general physical guidelines and suggestions are given, they may not necessarily guarantee adequate performance of the interconnect for all layouts and implementations. Therefore, designers should consider modeling and simulation of the interconnect in order to ensure compliance to all applicable specifications. The document is composed of two main sections. The first section provides an overview of general topology and interconnect guidelines. The second section concentrates on physical layout constraints where bulleted items at the beginning of a topic highlight important constraints, while the narrative that follows offers additional insight.
上傳時間： 2013-10-15
上傳用戶：busterman
A large group of fiber optic lasers are powered by DCcurrent. Laser drive is supplied by a current source withmodulation added further along the signal path. Thecurrent source, although conceptually simple, constitutesan extraordinarily tricky design problem. There are anumber of practical requirements for a fiber optic currentsource and failure to consider them can cause laser and/or optical component destruction.
上傳時間： 2013-10-30
上傳用戶：wanghui2438
AVR單片機實踐開發學習
標簽： Microcontrollers practical AVR
上傳時間： 2013-11-11
上傳用戶：tou15837271233
為了提高PCB板制作的效率，改變傳統的化學腐蝕制板工藝，使用機械仿形銑制作電路板的方法，設計了以ATMEGA16單片機為核心部件的PCB板雕刻機控制系統。其中包括PCB雕刻機的基本功能、主要硬件電路設計和軟件的實現流程，并給出了相關設計電路。重點分析了雕刻機步進電機的驅動電路以及主軸電機的驅動電路，該雕刻機經實際運行，系統工作良好，可有效提高PCB板的制作效率。 Abstract: In order to improve the efficiency of production of PCB board and change the traditional chemical etching plates， using of mechanical copying milling method makes circuit boards，this paper introduces the PCB engraving machine control system used ATMEGA16 microcomputer as the core components. It includes basic function， the hardware circuit design and software realization process， and gives the corresponding circuit design.It analyses the drive circuit of engrawing machine stepper motor and spindle motor in detail. This engraving machine by practical operation， the system works well， which can effectively improve the production efficiency of PCB board.
上傳時間： 2013-10-17
上傳用戶：liangliang123
數字控制的交流調速系統所選用的微處理器、功率器件及產生PWM波的方法是影響交流調速系統性能好壞的直接因素。在介紹了正弦脈寬調制(SPWM)技術的基礎上，設計了一種以8098單片機作為控制器，以智能功率模塊IPM為開關器件的變頻調速系統。通過軟件編程，產生正弦脈沖寬度調制波形來控制絕緣柵雙極晶體管的導通和關斷，從而達到控制異步電動機轉速的目的。實驗結果表明，該系統可調頻率調電壓，穩定度高，調速范圍寬，具有較強的實用價值 Abstract: AC variable speed with digital control systems used microprocessors， power devices and generate PWM wave is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology，this paper designed variable speed system which used 8098 as a controller， intelligent power module IPM as switching device. Through software programming， resulting in sinusoidal pulse width modulation waveform to control the insulated gate bipolar transistor turn on and off， so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation voltage， high stability， wide speed range， has a strong practical value.
上傳時間： 2013-11-14
上傳用戶：ynwbosss
在理論分析循環碼編碼和譯碼基本原理的基礎上，提出了基于單片機系統的(24，16)循環碼軟件實現編碼、譯碼的方案。仿真結果表明(24，16)循環碼能有效地克服來自通訊信道的干擾，保證數據通信的可靠及系統的穩定，使誤碼率大幅度降低。本論文對(24，16)循環碼的研究結果表明，可以有效地降低錯誤概率和提高系統的吞吐量，實現糾錯僅需要在接收端增加有限的存儲空間和計算復雜度，具有一定的實用價值。 Abstract: Based on analyzing the theory of encoding and decoding of cyclic code， this paper showed the schemes of encoding and decoding of(24，16)cyclic code by the software and based on microcontroller. Simulation results show that using (24，16) cyclic codes can effectively overcome the interference from communication channel， ensure the reliability and stability of data communication systems， and reduce the bit error rate greatly. The results of this paper show that by using the (24，16) cyclic code， the error rate can be reduced and the system throughput can be improved. Meanwhile， the system only needs to enlarge limited storage space and computation the complexity at the receiving end to realize error correction. Thus the (24，16) cyclic code has a practical value.
上傳時間： 2013-11-09
上傳用戶：gaoliangncepu
設計一種基于AT89C52的語音錄放系統，利用單片機、ISD2560語音錄放器件、麥克風、揚聲器等元器件實現硬件電路的設計，并利用C51高級語言設計ISD2560器件控制字的寫入和定時中斷程序。經軟硬件調試，結果表明該系統錄放效果良好，具有一定的工程實用價值。 Abstract: Voice recording and playback system based on AT89C52is designed in this paper.Using the single-chip microcomputer，voice recording and playback chip ISD2560，microphone and speaker to realize the hardware circuit design.Writing ISD2560control words and timing interrupt procedures are designed by C51advanced language.Through the hardware and software test,voice recording and playback system play better voice,and this system has some engineering practical values.
上傳時間： 2013-10-20
上傳用戶：ywcftc277
以89S52單片機和EP1C6Q240C8型FPGA為控制核心的多功能計數器，是由峰值檢波、A/D轉換、程控放大、比較整形、移相網絡部分組成,可實現測量正弦信號的頻率、周期和相位差的功能。多功能計數器采用等精度的測量方法，可實現頻率為1Hz～10MHz、幅度為0.01～5Vrms的正弦信號的精確測頻，以及頻率為10Hz～100kHz、幅度為0.5～5Vrms的正弦信號精確測相。液晶顯示器能夠實時顯示當前信號的頻率、周期和相位差。該多功能計數器精度高，界面友好，實用性強。 Abstract: A multi-function counter，which uses89S52MCU and EP1C6Q240C8FPGA as a control core，consists of peak detector，A/D conversion，program-controlled amplification，compared shaping and phase-shifting network part.The counter measures the frequency，period and phase of sinusoidal signal.With the equal precision method,the multi-function counter achieves the precise frequency measurement of the sinusoidal signal which its frequency is from1Hz to10MHz，its amplitude is from0.01Vrms to5Vrms，as well as the accurate phase measurement of the sinusoidal signal which its frequency is from10Hz to100kHz，its amplitude is from0.5Vrms to5Vrms.The LCD monitor real-time displays the frequency，period and phase difference of current signal.The multi-function counter features high precision，friendly interface，and strong practical.
上傳時間： 2013-11-15
上傳用戶：gy592333
