為滿足無線網(wǎng)絡(luò)技術(shù)具有低功耗、節(jié)點(diǎn)體積小、網(wǎng)絡(luò)容量大、網(wǎng)絡(luò)傳輸可靠等技術(shù)要求，設(shè)計(jì)了一種以MSP430單片機(jī)和CC2420射頻收發(fā)器組成的無線傳感節(jié)點(diǎn)。通過分析其節(jié)點(diǎn)組成，提出了ZigBee技術(shù)中的幾種網(wǎng)絡(luò)拓?fù)湫问剑⒀芯苛薢igBee路由算法。針對(duì)不同的傳輸要求形式選用不同的網(wǎng)絡(luò)拓?fù)湫问娇梢员M大可能地減少系統(tǒng)成本。同時(shí)針對(duì)不同網(wǎng)絡(luò)選用正確的ZigBee路由算法有效地減少了網(wǎng)絡(luò)能量消耗，提高了系統(tǒng)的可靠性。應(yīng)用試驗(yàn)表明，采用ZigBee方式通信可以提高傳輸速率且覆蓋范圍大，與傳統(tǒng)的有線通信方式相比可以節(jié)約40%左右的成本。 Abstract: To improve the proposed technical requirements such as low-ower， small nodes， large capacity and reliable network transmission， wireless sensor nodes based on MSP430 MCU and CC2420 RF transceiver were designed. This paper provided network topology of ZigBee technology by analysing the component of the nodes and researched ZigBee routing algorithm. Aiming at different requirements of transmission mode to choose the different network topologies form can most likely reduce the system cost. And aiming at different network to choose the correct ZigBee routing algorithm can effectively reduced the network energy consumption and improved the reliability of the system. Results show that the communication which used ZigBee mode can improve the transmission rate， cover more area and reduce 40% cost compared with traditional wired communications mode.
標(biāo)簽： ZigBee 無線傳感網(wǎng)絡(luò) 協(xié)議研究 路由
上傳時(shí)間： 2013-10-09
上傳用戶：robter
Single-Ended and Differential S-Parameters Differential circuits have been important incommunication systems for many years. In the past,differential communication circuits operated at lowfrequencies, where they could be designed andanalyzed using lumped-element models andtechniques. With the frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element techniques.Scattering parameters, or S-parameters, have beendeveloped for this purpose [1]. These S-parametersare defined for single-ended networks. S-parameterscan be used to describe differential networks, but astrict definition was not developed until Bockelmanand others addressed this issue [2]. Bockelman’swork also included a study on how to adapt single-ended S-parameters for use with differential circuits[2]. This adaptation, called “mixed-mode S-parameters,” addresses differential and common-mode operation, as well as the conversion betweenthe two modes of operation.This application note will explain the use of single-ended and mixed-mode S-parameters, and the basicconcepts of microwave measurement calibration.
上傳時(shí)間： 2014-03-25
上傳用戶：yyyyyyyyyy
The RT9018A/B is a high performance positive voltage regulator designed for use in applications requining very low Input voltage and very low dropout voltage at up to 3A(peak).
上傳時(shí)間： 2013-10-10
上傳用戶：geshaowei
提出了一種以ARM微處理器為控制核心的遠(yuǎn)程無線視頻監(jiān)控終端的設(shè)計(jì)方案，其監(jiān)控終端的硬件設(shè)計(jì)包括視頻采集處理、中央管理控制、無線傳輸3個(gè)模塊。并給出了監(jiān)控終端的軟件開發(fā)平臺(tái)和開發(fā)模式的系統(tǒng)啟動(dòng)代碼、嵌入式Linux系統(tǒng)移植以及驅(qū)動(dòng)程序和應(yīng)用程序。測(cè)試結(jié)果表明，該監(jiān)控終端設(shè)計(jì)方案合理、有效，基本滿足監(jiān)控需求。 Abstract: A remote wireless video monitoring terminal design， which uses ARM microprocessor as its core control， is proposed in this paper.The hardware design of monitoring terminal system is composed of the video acquisition and processing module， the central management and control module， wireless transmission module.Meanwhile the monitoring terminal-s software development platform and development patterns are designed. Also the design of the system-s start codes， embedded Linux system-s transplantation process， driver and the corresponding applications are given. The results showed that the monitoring terminal design is reasonable， effective， basically meet monitoring requirements.
標(biāo)簽： ARM 遠(yuǎn)程無線 視頻監(jiān)控 終端設(shè)計(jì)
上傳時(shí)間： 2013-11-13
上傳用戶：wanqunsheng
本軟件是關(guān)于MAX338, MAX339的英文數(shù)據(jù)手冊(cè)：MAX338, MAX339 8通道/雙4通道、低泄漏、CMOS模擬多路復(fù)用器 The MAX338/MAX339 are monolithic, CMOS analog multiplexers (muxes). The 8-channel MAX338 is designed to connect one of eight inputs to a common output by control of a 3-bit binary address. The dual, 4-channel MAX339 is designed to connect one of four inputs to a common output by control of a 2-bit binary address. Both devices can be used as either a mux or a demux. On-resistance is 400Ω max, and the devices conduct current equally well in both directions. These muxes feature extremely low off leakages (less than 20pA at +25°C), and extremely low on-channel leakages (less than 50pA at +25°C). The new design offers guaranteed low charge injection (1.5pC typ) and electrostatic discharge (ESD) protection greater than 2000V, per method 3015.7. These improved muxes are pin-compatible upgrades for the industry-standard DG508A and DG509A. For similar Maxim devices with lower leakage and charge injection but higher on-resistance, see the MAX328 and MAX329.
上傳時(shí)間： 2013-11-12
上傳用戶：18711024007
This application note provides a functional description of VHDL source code for a N x N DigitalCrosspoint Switch. The code is designed with eight inputs and eight outputs in order to targetthe 128-macrocell CoolRunner™-II CPLD device but can be easily expanded to target higherdensity devices. To obtain the VHDL source code described in this document, go to sectionVHDL Code, page 5 for instructions.
標(biāo)簽： CoolRunner-II XAPP CPLD 380
上傳時(shí)間： 2013-10-26
上傳用戶：kiklkook
針對(duì)傳統(tǒng)集成電路（ASIC）功能固定、升級(jí)困難等缺點(diǎn)，利用FPGA實(shí)現(xiàn)了擴(kuò)頻通信芯片STEL-2000A的核心功能。使用ISE提供的DDS IP核實(shí)現(xiàn)NCO模塊，在下變頻模塊調(diào)用了硬核乘法器并引入CIC濾波器進(jìn)行低通濾波，給出了DQPSK解調(diào)的原理和實(shí)現(xiàn)方法，推導(dǎo)出一種簡(jiǎn)便的引入?仔/4固定相移的實(shí)現(xiàn)方法。采用模塊化的設(shè)計(jì)方法使用VHDL語言編寫出源程序，在Virtex-II Pro 開發(fā)板上成功實(shí)現(xiàn)了整個(gè)系統(tǒng)。測(cè)試結(jié)果表明該系統(tǒng)正確實(shí)現(xiàn)了STEL-2000A的核心功能。 Abstract: To overcome drawbacks of ASIC such as fixed functionality and upgrade difficulty, FPGA was used to realize the core functions of STEL-2000A. This paper used the DDS IP core provided by ISE to realize the NCO module, called hard core multiplier and implemented CIC filter in the down converter, described the principle and implementation detail of the demodulation of DQPSK, and derived a simple method to introduce a fixed phase shift of ?仔/4. The VHDL source code was designed by modularity method , and the complete system was successfully implemented on Virtex-II Pro development board. Test results indicate that this system successfully realize the core function of the STEL-2000A.
標(biāo)簽： STEL 2000 FPGA 擴(kuò)頻通信
上傳時(shí)間： 2013-11-19
上傳用戶：neu_liyan
為了在CDMA系統(tǒng)中更好地應(yīng)用QDPSK數(shù)字調(diào)制方式，在分析四相相對(duì)移相（QDPSK)信號(hào)調(diào)制解調(diào)原理的基礎(chǔ)上，設(shè)計(jì)了一種QDPSK調(diào)制解調(diào)電路，它包括串并轉(zhuǎn)換、差分編碼、四相載波產(chǎn)生和選相、相干解調(diào)、差分譯碼和并串轉(zhuǎn)換電路。在MAX+PLUSⅡ軟件平臺(tái)上，進(jìn)行了編譯和波形仿真。綜合后下載到復(fù)雜可編程邏輯器件EPM7128SLC84-15中，測(cè)試結(jié)果表明，調(diào)制電路能正確選相，解調(diào)電路輸出數(shù)據(jù)與QDPSK調(diào)制輸入數(shù)據(jù)完全一致，達(dá)到了預(yù)期的設(shè)計(jì)要求。 Abstract: In order to realize the better application of digital modulation mode QDPSK in the CDMA system， a sort of QDPSK modulation-demodulation circuit was designed based on the analysis of QDPSK signal modulation-demodulation principles. It included serial/parallel conversion circuit, differential encoding circuit, four-phase carrier wave produced and phase chosen circuit, coherent demodulation circuit, difference decoding circuit and parallel/serial conversion circuit. And it was compiled and simulated on the MAX+PLUSⅡ software platform,and downloaded into the CPLD of EPM7128SLC84-15.The test result shows that the modulation circuit can exactly choose the phase，and the output data of the demodulator circuit is the same as the input data of the QDPSK modulate. The circuit achieves the prospective requirement of the design.
標(biāo)簽： QDPSK CPLD 調(diào)制解調(diào) 電路設(shè)計(jì)
上傳時(shí)間： 2013-10-28
上傳用戶：jyycc
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(shí)間： 2013-11-16
上傳用戶：萍水相逢
a8259 可編程中斷控制 altera提供 The a8259 is designed to simplify the implementation of the interrupt interface in 8088 and 8086 based microcomputer systems. The device is known as a programmable interrupt controller. The a8259 receives and prioritizes up to 8 interrupts, and in the cascade mode, this can be expanded up to 64 interrupts. An asynchronous reset and a clock input have been added to improve operation and reliability.
上傳時(shí)間： 2015-01-02
上傳用戶：panpanpan
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