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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.
標(biāo)簽：
Filters
Active
上傳時(shí)間：
2013-11-05
上傳用戶：AISINI005
-
Handheld electronic devices play a key role in our everydaylives. Because dependability is paramount, handhelds arecarefully engineered with lightweight power sources forreliable use under normal conditions. But no amount ofcareful engineering can prevent the mistreatment theywill undergo at the hands of humans. For example, whathappens when a factory worker drops a bar code scanner,causing the battery to pop out? Such events areelectronically unpredictable, and important data storedin volatile memory would be lost without some form ofsafety net—namely a short-term power holdup systemthat stores suffi cient energy to supply standby power untilthe battery can be replaced or the data can be stored inpermanent memory.
標(biāo)簽：
超級(jí)電容器
備用電源
手持設(shè)備
上傳時(shí)間：
2013-11-05
上傳用戶：coeus
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Designing Boards with Atmel AT89C51,AT89C52, AT89C1051, and AT89C2051 for Writing Flash at In-Circuit Test.
Recent improvements in chips and testers have made it possible for the tester to begin taking over the role tradi-tionally assigned to the PROM program-mer. Instead of having a PROM pro- grammer write nonvolatile memories before assembling the board, the in-cir- cuit tester writes them during in-circuit testing operations. Many Teradyne Z18- series testers are now in use loading code into nonvolatile memories, micro- controllers and in-circuit programmable logic devices. The purpose of this note is to explain how the Z18 approaches the writing task for Atmel AT89C series IC’s, so that designers of boards using these chips can get the best results.
標(biāo)簽：
Atmel
89C
AT
89
上傳時(shí)間：
2013-11-17
上傳用戶：xiaozhiqban
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匯編器在微處理器的驗(yàn)證和應(yīng)用中舉足輕重，如何設(shè)計(jì)通用的匯編器一直是研究的熱點(diǎn)之一。本文提出了一種開(kāi)放式的匯編器系統(tǒng)設(shè)計(jì)思想，在匯編語(yǔ)言與機(jī)器語(yǔ)言間插入中間代碼CMDL（code mapping description language）語(yǔ)言，打破匯編語(yǔ)言與機(jī)器語(yǔ)言的直接映射關(guān)系，由此建立起一套描述匯編語(yǔ)言與機(jī)器語(yǔ)言的開(kāi)放式映射體系。基于此開(kāi)放式映射體系開(kāi)發(fā)了一套匯編器系統(tǒng)，具有較高層次上的通用性和可移植性。【關(guān)鍵詞】指令集，CMDL，匯編器，開(kāi)放式
Design of Retargetable Assembler System Liu Ling Feng Wen Nan Wang Ying Chun Jiang An Ping Ji Li Jiu IME of Peking University, 100871【摘要】An assembler plays a very important role in the field of microprocessor verifications and applications, thus how to build a retargetable assembler system has been a hotspot in this field for long time. This paper presents a new method about the retargetable assembler system design.It provides a kind of language CMDL, code mapping description language. During the process of assembling, assembler languages are firstly translated to CMDL, and then mapped to the machine codes. In an other word, CMDL is inserted between assembler languages and machine codes during the translation procedure. As a medium code, CMDL has a lot of features, such as high extraction, strong descript capabilities. It can describe almost all attributes of assembler languages. By breaking the direct mapping relationship between assembler languages and machine codes, the complexities of machine codes are hided to the users, therefore, the new retargetable assembler system has higher retargetable level by converting the mapping from assembler languages and machine codes to assembler languages and CMDL, and implementationof it becomes easier. Based on the new mapping system structure, a retargetable assemblersystem is developed. It proved the whole system has good retargetability and implantability.【關(guān)鍵詞】instruction set, symbol table, assembler, lexical analysis, retargetability
標(biāo)簽：
開(kāi)放式
匯編器
上傳時(shí)間：
2013-10-10
上傳用戶：meiguiweishi
-
Designing Boards with Atmel AT89C51, AT89C52, AT89C1051, and AT89C2051 for Writing Flash at In-Circuit Test:Recent improvements in chips andtesters have made it possible for thetester to begin taking over the role traditionallyassigned to the PROM programmer.Instead of having a PROM programmerwrite nonvolatile memoriesbefore assembling the board, the in-circuittester writes them during in-circuittesting operations. Many Teradyne Z18-series testers are now in use loadingcode into nonvolatile memories, microcontrollersand in-circuit programmable logic devices. The purpose of this note is to explain how the Z18 approaches the writing task for Atmel AT89C series IC’s,so that designers of boards using these chips can get the best results.
標(biāo)簽：
Designing
Boards
Atmel
with
上傳時(shí)間：
2013-11-20
上傳用戶：lijianyu172
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The 87LPC76X Microcontroller combines in a small package thebenefits of a high-performance microcontroller with on-boardhardware supporting the Inter-Integrated Circuit (I2C) bus interface.The 87LPC76X can be programmed both as an I2C bus master, aslave, or both. An overview of the I2C bus and description of the bussupport hardware in the 87LPC76X microcontrollers appears inapplication note AN464, Using the 87LPC76X Microcontroller as anI2C Bus Master. That application note includes a programmingexample, demonstrating a bus-master code. Here we show anexample of programming the microcontroller as an I2C slave.The code listing demonstrates communications routines for the87LPC76X as a slave on the I2C bus. It compliments the program inAN464 which demonstrates the 87LPC76X as an I2C bus master.One may demonstrate two 87LPC76X devices communicating witheach other on the I2C bus, using the AN464 code in one, and theprogram presented here in the other. The examples presented hereand in AN464 allow the 87LPC76X to be either a master or a slave,but not both. Switching between master and slave roles in amultimaster environment is described in application note AN435.The software for a slave on the bus is relatively simple, as theprocessor plays a relatively passive role. It does not initiate bustransfers on its own, but responds to a master initiating thecommunications. This is true whether the slave receives or transmitsdata—transmission takes place only as a response to a busmaster’s request. The slave does not have to worry about arbitrationor about devices which do not acknowledge their address. As theslave is not supposed to take control of the bus, we do not demandit to resolve bus exceptions or “hangups”. If the bus becomesinactive the processor simply withdraws, not interfering with themaster (or masters) on the bus which should (hopefully) try toresolve the situation.
標(biāo)簽：
routines
slave
I2C
87L
上傳時(shí)間：
2013-11-19
上傳用戶：shirleyYim
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The exacting technological demands created byincreasing bandwidth requirements have given riseto significant advances in FPGA technology thatenable engineers to successfully incorporate highspeedI/O interfaces in their designs. One aspect ofdesign that plays an increasingly important role isthat of the FPGA package. As the interfaces get fasterand wider, choosing the right package has becomeone of the key considerations for the systemdesigner.
標(biāo)簽：
Virtex
247
WP
高級(jí)封裝
上傳時(shí)間：
2013-10-22
上傳用戶：1234xhb
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The #1 Step-by-Step Guide to labviewNow Completely Updated for labview 8!
Master labview 8 with the industry's friendliest, most intuitive tutorial: labview for Everyone, Third Edition. Top labview experts Jeffrey Travis and Jim Kring teach labview the easy way: through carefully explained, step-by-step examples that give you reusable code for your own projects!
This brand-new Third Edition has been fully revamped and expanded to reflect new features and techniques introduced in labview 8. You'll find two new chapters, plus dozens of new topics, including Project Explorer, AutoTool, XML, event-driven programming, error handling, regular expressions, polymorphic VIs, timed structures, advanced reporting, and much more. Certified labview Developer (CLD) candidates will find callouts linking to key objectives on NI's newest exam, making this book a more valuable study tool than ever.
Not just what to d why to do it!
Use labview to build your own virtual workbench
Master labview's foundations: wiring, creating, editing, and debugging VIs; using controls and indicators; working with data structures; and much more
Learn the "art" and best practices of effective labview development
NEW: Streamline development with labview Express VIs
NEW: Acquire data with NI-DAQmx and the labview DAQmx VIs
NEW: Discover design patterns for error handling, control structures, state machines, queued messaging, and more
NEW: Create sophisticated user interfaces with tree and tab controls, drag and drop, subpanels, and more
Whatever your application, whatever your role, whether you've used labview or not, labview for Everyone, Third Edition is the fastest, easiest way to get the results you're after!
標(biāo)簽：
Everyone
LabVIEW
for
英文
上傳時(shí)間：
2013-10-14
上傳用戶：shawvi
-
The exacting technological demands created byincreasing bandwidth requirements have given riseto significant advances in FPGA technology thatenable engineers to successfully incorporate highspeedI/O interfaces in their designs. One aspect ofdesign that plays an increasingly important role isthat of the FPGA package. As the interfaces get fasterand wider, choosing the right package has becomeone of the key considerations for the systemdesigner.
標(biāo)簽：
Virtex
247
WP
高級(jí)封裝
上傳時(shí)間：
2013-11-07
上傳用戶：wanghui2438
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股票交易模擬器
A Stock Exchange simulator to show timers and randon number generators work together. A cool simulation for anyone who might think about playing the stocks and spending money and get a general idea how the system works.
標(biāo)簽：
generators
simulator
Exchange
together
上傳時(shí)間：
2015-04-13
上傳用戶：愛(ài)死愛(ài)死
