隨著計(jì)算機(jī)技術(shù)、通信技術(shù)的飛速發(fā)展和3C(計(jì)算機(jī)、通信、消費(fèi)電子)的融合，嵌入式系統(tǒng)已經(jīng)滲透到各個(gè)領(lǐng)域。在32位嵌入式微處理器市場(chǎng)上，基于ARM(Advanced RISC Machine)內(nèi)核的微處理器在市場(chǎng)上處于絕對(duì)的領(lǐng)導(dǎo)地位，因此追蹤ARM技術(shù)的發(fā)展趨勢(shì)顯得尤為重要。在嵌入式操作系統(tǒng)的選擇上，Linux一直因其內(nèi)核精簡(jiǎn)、代碼開(kāi)放、易于移植等特點(diǎn)受到廣大嵌入式系統(tǒng)工程師的青睞。另外，嵌入式系統(tǒng)一旦具備網(wǎng)絡(luò)接入功能，其信息處理能力更加強(qiáng)大，因此有必要為嵌入式系統(tǒng)構(gòu)建Web服務(wù)器。 本文主要目的是研究基于ARM的嵌入式Linux開(kāi)發(fā)平臺(tái)構(gòu)建，并在此基礎(chǔ)上進(jìn)行網(wǎng)絡(luò)應(yīng)用程序的開(kāi)發(fā)。 文章深入剖析了ARM9的體系結(jié)構(gòu)，介紹了基于ARM9的S3C2410開(kāi)發(fā)板的特性及資源；闡述了嵌入式操作系統(tǒng)的相關(guān)知識(shí)及嵌入式Linux移植的基本方法；搭建了移植所需要的開(kāi)發(fā)環(huán)境，主要包括在宿主機(jī)Linux操作系統(tǒng)下編譯arm-linux交叉編譯工具等；然后詳細(xì)闡述了嵌入式Linux開(kāi)發(fā)平臺(tái)的構(gòu)建過(guò)程，包括對(duì)BootLoader的分析和移植，Linux2.6內(nèi)核的結(jié)構(gòu)分析、代碼修改以及內(nèi)核裁減、配置和移植，網(wǎng)卡驅(qū)動(dòng)程序的移植，以及根文件系統(tǒng)的創(chuàng)建。按文中提供的方法和技巧可以很方便的建立一個(gè)ARM-Linux開(kāi)發(fā)平臺(tái)。 文章最后給出了基于所建平臺(tái)的網(wǎng)絡(luò)應(yīng)用，即在上述所建的軟硬件平臺(tái)上創(chuàng)建Web服務(wù)器Boa，并基于Boa進(jìn)行應(yīng)用開(kāi)發(fā)。最終實(shí)現(xiàn)了基于Boa嵌入式Web服務(wù)器的服務(wù)器端表單處理程序，實(shí)現(xiàn)了PC機(jī)與目標(biāo)板的動(dòng)態(tài)網(wǎng)頁(yè)交互功能，并且，通過(guò)PC機(jī)IE瀏覽器可以直接控制目標(biāo)板上的硬件和可執(zhí)行程序，以實(shí)現(xiàn)對(duì)目標(biāo)板的遠(yuǎn)程監(jiān)控功能。
上傳時(shí)間： 2013-04-24
上傳用戶：kernaling
光纖水聽(tīng)器自問(wèn)世以來(lái)，在巨大的軍事價(jià)值和民用價(jià)值推動(dòng)下得到了迅速發(fā)展，已逐漸從實(shí)驗(yàn)室研究階段走向工程應(yīng)用。同時(shí)隨著光纖水聽(tīng)器的不斷發(fā)展，對(duì)水聲信號(hào)的檢測(cè)技術(shù)以及數(shù)字處理能力也提出了新的要求。論文在此背景下開(kāi)展了一系列研究工作，并提出了利用FPGA(Field ProgrammableGate Array，現(xiàn)場(chǎng)可編程門(mén)陣列)實(shí)現(xiàn)光纖3×3耦合器解調(diào)算法的新思路。 目前干涉型光纖水聽(tīng)器的解調(diào)一般采用PGC(Phase Generated Carrier，相位生成載波技術(shù))技術(shù)和基于3×3光纖耦合器干涉的解調(diào)技術(shù)。PGC技術(shù)在解調(diào)過(guò)程中引入了載波信號(hào)，它對(duì)采樣率，激光器等的要求都較高，因此我們把目光投向3×3耦合器解調(diào)技術(shù)，文中對(duì)其解調(diào)原理進(jìn)行了闡述，對(duì)采樣率的確定進(jìn)行了討論，并對(duì)3×3耦合器三路輸出不對(duì)稱的情況進(jìn)行了分析，最后在本文的結(jié)論部分提出了基于3×3耦合器解調(diào)的改良方案。 目前，光纖信號(hào)數(shù)字化解調(diào)的硬件實(shí)現(xiàn)采用DSP(Digital Signal Process，可編程數(shù)字信號(hào)處理器)信號(hào)處理機(jī)，與之相比，F(xiàn)PGA解調(diào)具有速度快、資源占用少、易于擴(kuò)展等優(yōu)勢(shì)。本文對(duì)FPGA與DSP、ASIC(application-specificintegrated circuit，專用集成電路)實(shí)現(xiàn)方案進(jìn)行了對(duì)比，分析了適合利用FPGA實(shí)現(xiàn)的算法所應(yīng)具備的特征；介紹了3×3耦合器解調(diào)算法中各個(gè)模塊的設(shè)計(jì)情況；分析了系統(tǒng)的工作情況，硬件的構(gòu)造及芯片的選擇，最后驗(yàn)證了利用FPGA可以實(shí)現(xiàn)3×3耦合器解調(diào)算法。
標(biāo)簽： 干涉型 光纖水聽(tīng)器 信號(hào)解調(diào) 方法研究
上傳時(shí)間： 2013-07-03
上傳用戶：love1314
·【英文題名】 Search of Double-fed Machine Variable Speed System Based on DSP 【作者中文名】 沈睿; 【導(dǎo)師】 廖冬初; 【學(xué)位授予單位】 湖北工業(yè)大學(xué); 【學(xué)科專業(yè)名稱】 控制理論與控制工程 【學(xué)位年度】 2007 【論文級(jí)別】 碩士 【網(wǎng)絡(luò)出版投稿人】 湖北工業(yè)大學(xué) 【網(wǎng)絡(luò)出版投稿時(shí)間】 2008-09-27 【關(guān)鍵詞】 雙饋調(diào)速
標(biāo)簽： DSP 雙饋 電機(jī)調(diào)速系統(tǒng)
上傳時(shí)間： 2013-04-24
上傳用戶：hanwu
虛擬機(jī)自省（Virtual Machine Introspection，VMI）技術(shù)充分利用虛擬機(jī)管理器的較高權(quán)限，可以實(shí)現(xiàn)在單獨(dú)的虛擬機(jī)中部署安全工具對(duì)目標(biāo)虛擬機(jī)進(jìn)行監(jiān)測(cè)，為進(jìn)行各種安全研究工作提供了很好的解決途徑，從而隨著虛擬化技術(shù)的發(fā)展成為一種應(yīng)用趨勢(shì)。基于為更深入的理解和更好的應(yīng)用VMI技術(shù)提供參考作用的目的，本文對(duì)VMI技術(shù)進(jìn)行了分析研究。采用分析總結(jié)的方法，提出了VMI的概念，分析其實(shí)現(xiàn)原理和實(shí)現(xiàn)方式；詳細(xì)地分析總結(jié)了VMI技術(shù)在不同領(lǐng)域的研究進(jìn)展，通過(guò)對(duì)不同研究成果根據(jù)實(shí)現(xiàn)方式進(jìn)行交叉分析比較，得出不同研究成果對(duì)應(yīng)的4種實(shí)現(xiàn)方式；分析了VMI技術(shù)面臨的語(yǔ)義鴻溝問(wèn)題；最后對(duì)VMI技術(shù)研究進(jìn)行總結(jié)和展望。
上傳時(shí)間： 2014-08-21
上傳用戶：jkhjkh1982
The purpose of this application note is to show an example of how a digital potentiometer can be used in thefeedback loop of a step-up DC-DC converter to provide calibration and/or adjustment of the output voltage.The example circuit uses a MAX5025 step-up DC-DC converter (capable of generating up to 36V,120mWmax) in conjunction with a DS1845, 256 position, NV digital potentiometer. For this example, the desiredoutput voltage is 32V, which is generated from an input supply of 5V. The output voltage can be adjusted in35mV increments (near 32V) and span a range wide enough to account for resistance, potentiometer and DCDCconverter tolerances (27.6V to 36.7V).
標(biāo)簽： DC-DC 數(shù)字電位器 升壓型 校準(zhǔn)
上傳時(shí)間： 2014-12-23
上傳用戶：781354052
This application note describes a Linear Technology "Half-Flash" A/D converter, the LTC1099, being connected to a 256 element line scan photodiode array. This technology adapts itself to handheld (i.e., low power) bar code readers, as well as high resolution automated machine inspection applications..
標(biāo)簽： 1099 LTC 8位 AD轉(zhuǎn)換
上傳時(shí)間： 2013-11-21
上傳用戶：lchjng
設(shè)計(jì)了水聲信號(hào)發(fā)生系統(tǒng)中的功率放大電路，可將前級(jí)電路產(chǎn)生的方波信號(hào)轉(zhuǎn)換為正弦信號(hào)，同時(shí)進(jìn)行濾波、功率放大，使其滿足換能器對(duì)輸入信號(hào)的要求。該電路以單片機(jī)AT89C52，集成6階巴特沃思低通濾波芯片MF6以及大功率運(yùn)算放大器LM12為核心，通過(guò)標(biāo)準(zhǔn)RS232接口與PC進(jìn)行通信，實(shí)現(xiàn)信號(hào)增益的程控調(diào)節(jié)，對(duì)干擾信號(hào)具有良好的抑制作用。經(jīng)調(diào)試該電路工作穩(wěn)定正常，輸出波形無(wú)失真，在輸出功率以及放大增益、波紋系數(shù)等方面均滿足設(shè)計(jì)要求。 This paper presented a design and implementation of underwater acoustic power amplifer. This circuit converted the rectangle signal generated by frontend circuit into the sine signal， then filtered and power amplification， it meets the requirements of the transducer.Included AT89C52， 6th order Butterworth filter MF6， hipower amplififier LM12.Communication with PC through the RS232 port. The signal gain is adjustable and could be remote controlled. It has a good inhibitory effect on the interference signal. After debugged， this circuit works stable， the output waveform has no distortion， it meets the design requirement in outprt power， amplifier gain and ripple factor.
上傳時(shí)間： 2013-11-20
上傳用戶：qwe1234
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(shí)間： 2013-11-05
上傳用戶：AISINI005
Finite state machines are widely used in digital circuit designs. Generally, when designing a state machine using an HDL, the synthesis tools will optimize away all states that cannot be reached and generate a highly optimized circuit. Sometimes, however, the optimization is not acceptable. For example, if the circuit powers up in an invalid state, or the circuit is in an extreme working environment and a glitch sends it into an undesired state, the circuit may never get back to its normal operating condition.
標(biāo)簽： Creating Machines Mentor State
上傳時(shí)間： 2013-10-08
上傳用戶：wangzhen1990
Abstract: It may sound trite, but it is definitely true: the smart grid has the potential to completely transform the energyindustry. However, smart meters and grid management alone will not ensure the success of the smart grid. Unliketraditional IT networks, smart grids require consideration of energy measurement and security. To completely optimize thistechnology, smart grid designs must focus on energy measurement and security. This tutorial considers the benefits ofboth energy measurement and security and how they make machine-to-machine networks different from traditional IT.
標(biāo)簽： 電能計(jì)量 安全性 智能電網(wǎng)
上傳時(shí)間： 2013-10-29
上傳用戶：皇族傳媒
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