Control systems are becoming increasingly dependent on digital processing and so require sensors able to provide direct digital inputs. Sensors based on time measurement, having outputs based on a frequency or phase, have an advantage over conventional analogue sensors in that their outputs can be measured directly in digital systems by pulse counting.
上傳時間： 2013-10-08
上傳用戶：wuyuying
A complete design for a data acquisition card for the IBM PC is detailed in this application note. Additionally, C language code is provided to allow sampling of data at speed of more than 20kHz. The speed limitation is strictly based on the execution speed of the "C" data acquisition loop. A "Turbo" XT can acquire data at speeds greater than 20kHz. Machines with 80286 and 80386 processors can go faster than 20kHz. The computer that was used as a test bed in this application was an XT running at 4.77MHz and therefore all system timing and acquisition time measurements are based on a 4.77MHz clock speed.
標(biāo)簽： 1099 LTC 數(shù)據(jù) 采集板
上傳時間： 2013-10-29
上傳用戶：BOBOniu
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
上傳時間： 2013-11-21
上傳用戶：lchjng
Low power operation of electronic apparatus has becomeincreasingly desirable. Medical, remote data acquisition,power monitoring and other applications are good candidatesfor battery driven, low power operation. Micropoweranalog circuits for transducer-based signal conditioningpresent a special class of problems. Although micropowerICs are available, the interconnection of these devices toform a functioning micropower circuit requires care. (SeeBox Sections, “Some Guidelines for Micropower Designand an Example” and “Parasitic Effects of Test Equipmenton Micropower Circuits.”) In particular, trade-offs betweensignal levels and power dissipation become painful whenperformance in the 10-bit to 12-bit area is desirable.
標(biāo)簽： 信號調(diào)理 微電路
上傳時間： 2013-10-22
上傳用戶：rocketrevenge
The equal-area theorem●This is sinusoidal PWM (SPWM)●The equal-area theorem can be appliedto realize any shape of waveforms ●Natural sampling●Calculation based on equal-area criterion●Selected harmonic elimination●Regular sampling●Hysteresis-band control●Triangular wave comparison withfeedback control
上傳時間： 2013-11-22
上傳用戶：linyao
Radio Frequency Integrated Circuit Design I enjoyed reading this book for a number of reasons. One reason is that itaddresses high-speed analog design in the context of microwave issues. This isan advanced-level book, which should follow courses in basic circuits andtransmission lines. Most analog integrated circuit designers in the past workedon applications at low enough frequency that microwave issues did not arise.As a consequence, they were adept at lumped parameter circuits and often notcomfortable with circuits where waves travel in space. However, in order todesign radio frequency (RF) communications integrated circuits (IC) in thegigahertz range, one must deal with transmission lines at chip interfaces andwhere interconnections on chip are far apart. Also, impedance matching isaddressed, which is a topic that arises most often in microwave circuits. In mycareer, there has been a gap in comprehension between analog low-frequencydesigners and microwave designers. Often, similar issues were dealt with in twodifferent languages. Although this book is more firmly based in lumped-elementanalog circuit design, it is nice to see that microwave knowledge is brought inwhere necessary.Too many analog circuit books in the past have concentrated first on thecircuit side rather than on basic theory behind their application in communications.The circuits usually used have evolved through experience, without asatisfying intellectual theme in describing them. Why a given circuit works bestcan be subtle, and often these circuits are chosen only through experience. Forthis reason, I am happy that the book begins first with topics that require anintellectual approach—noise, linearity and filtering, and technology issues. Iam particularly happy with how linearity is introduced (power series). In therest of the book it is then shown, with specific circuits and numerical examples,how linearity and noise issues arise.
標(biāo)簽： Rogers Radio John Freq
上傳時間： 2014-12-23
上傳用戶：han_zh
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
上傳時間： 2013-10-08
上傳用戶：wangzhen1990
Integrated EMI/Thermal Design forSwitching Power SuppliesWei ZhangThesis submitted to the Faculty of theVirginia Polytechnic Institute and State Universityin partial fulfillment of the requirements for the degree of Integrated EMI/Thermal Design forSwitching Power SuppliesWei Zhang(ABSTRACT)This work presents the modeling and analysis of EMI and thermal performancefor switch power supply by using the CAD tools. The methodology and design guidelinesare developed.By using a boost PFC circuit as an example, an equivalent circuit model is builtfor EMI noise prediction and analysis. The parasitic elements of circuit layout andcomponents are extracted analytically or by using CAD tools. Based on the model, circuitlayout and magnetic component design are modified to minimize circuit EMI. EMI filtercan be designed at an early stage without prototype implementation.In the second part, thermal analyses are conducted for the circuit by using thesoftware Flotherm, which includes the mechanism of conduction, convection andradiation. Thermal models are built for the components. Thermal performance of thecircuit and the temperature profile of components are predicted. Improved thermalmanagement and winding arrangement are investigated to reduce temperature.In the third part, several circuit layouts and inductor design examples are checkedfrom both the EMI and thermal point of view. Insightful information is obtained.
標(biāo)簽： EMI 開關(guān)電源 英文
上傳時間： 2013-11-10
上傳用戶：1595690
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)
上傳時間： 2013-10-29
上傳用戶：皇族傳媒
Power over Ethernet (PoE) is a new development thatallows for the delivery of power to Ethernet-based devicesvia standard Ethernet CAT5 cable, precluding the need forwall adapters or other external power sources. The PoEspecification defines a hardware detection protocol wherePower Sourcing Equipment (PSE) is able to identify PoEPowered Devices (PDs), thus allowing full backwardscompatibility with non-PoE-aware (legacy) Ethernetdevices.
標(biāo)簽： PoE 電池電路 擴(kuò)展 以太網(wǎng)供電
上傳時間： 2013-11-11
上傳用戶：daoyue
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