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
As logic systems get larger and more complex, theirsupply current REQUIREMENTS continue to rise. Systemsrequiring 100A are fairly common. A high current powersupply to meet such REQUIREMENTS usually requires parallelingseveral power regulators to alleviate the thermalstress on the individual power components. A powersupply designer is left with the choice of how to drive theseparalleled regulators: brute-force single-phase or smartPolyPhaseTM.
上傳時間： 2013-10-08
上傳用戶：zhqzal1014
In an increasing trend, telecommunications, networking,audio and instrumentation require low noise power supplies.In particular, there is interest in low noise, lowdropout linear regulators (LDO). These components powernoise-sensitive circuitry, circuitry that contains noisesensitiveelements or both. Additionally, to conserve power,particularly in battery driven apparatus such as cellulartelephones, the regulators must operate with low input-tooutputvoltages.1 Devices presently becoming availablemeet these REQUIREMENTS (see separate section, “A Familyof 20mVRMS Noise, Low Dropout Regulators”).
上傳時間： 2013-10-30
上傳用戶：yeling1919
在航電系統維護過程中，為解決定位故障的效率和降低維修成本等問題，提出了基于ICD（Interface Control Document，接口控制文件）的1553B總線的信息監控系統模型。該系統運用數據采集卡對總線中傳輸的信號有無失真、偏差等電氣特性進行檢測，并使用1553B通訊卡通過測控軟件LabWindows/CVI編程與ICD數據庫的動態鏈接，實現總線信息的解析和故障的判斷。與傳統的維護過程相比，這種模型能夠從信號的電氣特性以及信息的解析等全方位的去檢測判斷故障的來源，并且能夠廣泛在其他1553B總線系統內擴展應用。驗證表明該監控系統可以對總線信息進行快速有效地監測分析，能滿足應用需求。 Abstract: In the process of avionics system maintenance， to solve the problems such as improving the efficiency of fast orientation to troubles and reducing maintenance cost， system of 1553B bus information monitor model based on ICD was proposed. The system observed whether the data which transmitted on the bus appear distortion and deviation by using data acquisition card. And using 1553B communication card programming of the measure software LabWindows/CVI and the dynamic linking of ICD database， message analysis and fault estimation could be realized. Compared with traditional maintenance， this model can all-dimensionally detect and analyze the source of faults from both electrical characteristics of the signal and message analysis， and it can be widely applied in the other 1553B system. Experiment shown that this monitor system can effectively detect and analyze the bus message and can meet the application REQUIREMENTS.
上傳時間： 2013-11-23
上傳用戶：18752787361
以AVR單片機ATmega8和USB接口器件PDIUSBD12為核心，基于標準的USB1.1協議，設計一種通用USB接口模塊，以滿足嵌入式系統中對USB接口的需求。對模塊的硬件電路或單片機固件程序的硬件接口層稍加修改即可用于其他各種微處理器。該模塊可為各種嵌入式系統增加USB接口,實現與USB主機系統通信。 Abstract: Based on AVR microcontroller ATmega8 and USB interface chip PDIUSBD12, a general USB interface module is designed according to USB1.1 protocol for various REQUIREMENTS of embedded systems. Only with few modifications in circuit or hardware abstract layer of firmware, the module can be used on many types of microprocessors. All kinds of embedded systems can realize high speed and stable communication with USB host systems, owing to the facility of this module.
上傳時間： 2014-01-08
上傳用戶：趙云興
介紹了基于單片機航空交流電參數測試儀的系統設計。以Silicon Labs公司的C8051F005單片機為核心設計出數據采集板，通過RS-232串口與上位機通訊。運用Lab Windows/CVI編寫的上位機軟件實現信號的檢測以及波形和數據的顯示，給出了測試儀硬件電路的組成和軟件流程圖。本系統具有硬件結構簡單、容易實現和成本低等特點，在實際應用中其穩定性、精確性均能滿足客戶要求。 Abstract: The design of aeronautics AC parameters tester based on the single-chip is introduced.The core component of data acquisition board is C8051F005 single chip of Silicon Labs Company,and communication with PC through RS-232. The signal processing software programmed with LabWindows/CVI can be used successfully to fulfill inspection of signal and display of the waveform and data. The hardware and software configuration of test instrument are provided.The hardware of the system is simple, and can be easily realized.The stability and precision of the measurement instrument are enough to meet the REQUIREMENTS.
上傳時間： 2013-11-18
上傳用戶：wang5829
Although Stellaris microcontrollers have generous internal SRAM capabilities, certain applicationsmay have data storage REQUIREMENTS that exceed the 8 KB limit of the Stellaris LM3S8xx seriesdevices. Since microcontrollers do not have an external parallel data-bus, serial memory optionsmust be considered. Until recently, the ubiquitous serial EEPROM/flash device was the only serialmemory solution. The major limitations of EEPROM and flash technology are slow write speed, slowerase times, and limited write/erase endurance.Recently, serial SRAM devices have become available as a solution for high-speed dataapplications. The N256S08xxHDA series of devices, from AMI Semiconductor, offer 32 K x 8 bits oflow-power data storage, a fast Serial Peripheral Interface (SPI) serial bus, and unlimited write cycles.The parts are available in 8-pin SOIC and compact TSSOP packages.
上傳時間： 2013-10-14
上傳用戶：cxl274287265
The MAX3243E device consists of three line drivers, five line receivers, and a dual charge-pump circuit with±15-kV ESD (HBM and IEC61000-4-2, Air-Gap Discharge) and ±8-kV ESD (IEC61000-4-2, Contact Discharge)protection on serial-port connection pins. The device meets the REQUIREMENTS of TIA/EIA-232-F and provides theelectrical interface between an asynchronous communication controller and the serial-port connector. Thiscombination of drivers and receivers matches that needed for the typical serial port used in an IBM PC/AT, orcompatible. The charge pump and four small external capacitors allow operation from a single 3-V to 5.5-Vsupply. In addition, the device includes an always-active noninverting output (ROUT2B), which allowsapplications using the ring indicator to transmit data while the device is powered down. The device operates atdata signaling rates up to 250 kbit/s and a maximum of 30-V/ms driver output slew rate.
標簽： MULTICHANNEL 5.5 TO RS
上傳時間： 2013-10-19
上傳用戶：ddddddd
The 87C576 includes two separate methods of programming theEPROM array, the traditional modified Quick-Pulse method, and anew On-Board Programming technique (OBP).Quick Pulse programming is a method using a number of devicepins in parallel (see Figure 1) and is the traditional way in which87C51 family members have been programmed. The Quick-Pulsemethod supports the following programming functions:– program USER EPROM– verify USER EPROM– program KEY EPROM– program security bits– verify security bits– read signature bytesThe Quick-Pulse method is quite easily suited to standardprogramming equipment as evidenced by the numerous vendors of87C51 compatible programmers on the market today. Onedisadvantage is that this method is not well suited to programming inthe embedded application because of the large number of signallines that must be isolated from the application. In addition, parallelsignals from a programmer would need to be cabled to theapplication’s circuit board, or the application circuit board wouldneed to have logic built-in to perform the programming functions.These REQUIREMENTS have generally made in-circuit programmingusing the modified Quick Pulse method impractical in almost all87C51 family applications.
上傳時間： 2013-10-21
上傳用戶：xiaozhiqban
This white paper discusses how market trends, the need for increased productivity, and new legislation have accelerated the use of safety systems in industrial machinery. This TÜV-qualified FPGA design methodology is changing the paradigms of safety designs and will greatly reduce development effort, system complexity, and time to market. This allows FPGA users to design their own customized safety controllers and provides a significant competitive advantage over traditional microcontroller or ASIC-based designs. Introduction The basic motivation of deploying functional safety systems is to ensure safe operation as well as safe behavior in cases of failure. Examples of functional safety systems include train brakes, proximity sensors for hazardous areas around machines such as fast-moving robots, and distributed control systems in process automation equipment such as those used in petrochemical plants. The International Electrotechnical Commission’s standard, IEC 61508: “Functional safety of electrical/electronic/programmable electronic safety-related systems,” is understood as the standard for designing safety systems for electrical, electronic, and programmable electronic (E/E/PE) equipment. This standard was developed in the mid-1980s and has been revised several times to cover the technical advances in various industries. In addition, derivative standards have been developed for specific markets and applications that prescribe the particular REQUIREMENTS on functional safety systems in these industry applications. Example applications include process automation (IEC 61511), machine automation (IEC 62061), transportation (railway EN 50128), medical (IEC 62304), automotive (ISO 26262), power generation, distribution, and transportation. 圖Figure 1. Local Safety System
上傳時間： 2013-11-05
上傳用戶：維子哥哥
