为满足无线网络技术具有低功耗、节点体积小、网络容量大、网络传输可靠等技术要求，设计了一种以MSP430单片机和CC2420射频收发器组成的无线传感节点。通过分析其节点组成，提出了ZigBee技术中的几种网络拓扑形式，并研究了ZigBee路由算法。针对不同的传输要求形式选用不同的网络拓扑形式可以尽大可能地减少系统成本。同时针对不同网络选用正确的ZigBee路由算法有效地减少了网络能量消耗，提高了系统的可靠性。应用试验表明，采用ZigBee方式通信可以提高传输速率且覆盖范围大，与传统的有线通信方式相比可以节约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.
ass="tags">标签： ZigBee 无线传感网络 协议研究 路由
ass="time">上传时间： 2013-10-09
ass="username">上传用户：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frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element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.
ass="time">上传时间： 2014-03-25
ass="username">上传用户：yyyyyyyyyy
Agilent AN 154 S-Parameter Design Application Note S参数的设计与应用 The need for new high-frequency, solid-state circuitdesign techniques has been recognized both by microwaveengineers and circuit designers. These engineersare being asked to design solid state circuitsthat will operate at higher and higher frequencies.The development of microwave transistors andAgilent Technologies’ network analysis instrumentationsystems that permit complete network characterizationin the microwave frequency rangehave greatly assisted these engineers in their work.The Agilent Microwave Division’s lab staff hasdeveloped a high frequency circuit design seminarto assist their counterparts in R&D labs throughoutthe world. This seminar has been presentedin a number of locations in the United States andEurope.From the experience gained in presenting this originalseminar, we have developed a four-part videotape, S-Parameter Design Seminar. While the technologyof high frequency circuit design is everchanging, the concepts upon which this technologyhas been built are relatively invariant.The content of the S-Parameter Design Seminar isas follows:
ass="tags">标签： S参数
ass="time">上传时间： 2013-12-19
ass="username">上传用户：aa54
提出了一种以ARM微处理器为控制核心的远程无线视频监控终端的设计方案，其监控终端的硬件设计包括视频采集处理、中央管理控制、无线传输3个模块。并给出了监控终端的软件开发平台和开发模式的系统启动代码、嵌入式Linux系统移植以及驱动程序和应用程序。测试结果表明，该监控终端设计方案合理、有效，基本满足监控需求。 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.
ass="tags">标签： ARM 远程无线 视频监控 终端设计
ass="time">上传时间： 2013-11-13
ass="username">上传用户：wanqunsheng
The LPC1850/30/20/10 are ARM Cortex-M3 based microcontrollers for embeddedapplications. The ARM Cortex-M3 is a next generation core that offers systemenhancements such as low power consumption, enhanced debug features, and a highlevel of support block integration.The LPC1850/30/20/10 operate at CPU frequencies of up to 150 MHz. The ARMCortex-M3 CPU incorporates a 3-stage pipeline and uses a Harvard architecture withseparate local instruction and data buses as well as a third bus for peripherals. The ARMCortex-M3 CPU also includes an internal prefetch unit that supports speculativebranching.The LPC1850/30/20/10 include up to 200 kB of on-chip SRAM data memory, a quad SPIFlash Interface (SPIFI), a State Configuration Timer (SCT) subsystem, two High-speedUSB controllers, Ethernet, LCD, an external memory controller, and multiple digital andanalog peripherals.
ass="tags">标签： Cortex-M 1850 LPC 内核微控制器
ass="time">上传时间： 2014-12-31
ass="username">上传用户：zhuoying119
The LPC4350/30/20/10 are ARM Cortex-M4 based microcontrollers for embeddedapplications. The ARM Cortex-M4 is a next generation core that offers systemenhancements such as low power consumption, enhanced debug features, and a highlevel of support block integration.The LPC4350/30/20/10 operate at CPU frequencies of up to 150 MHz. The ARMCortex-M4 CPU incorporates a 3-stage pipeline, uses a Harvard architecture withseparate local instruction and data buses as well as a third bus for peripherals, andincludes an internal prefetch unit that supports speculative branching. The ARMCortex-M4 supports single-cycle digital signal processing and SIMD instructions. Ahardware floating-point processor is integrated in the core.The LPC4350/30/20/10 include an ARM Cortex-M0 coprocessor, up to 264 kB of datamemory, advanced configurable peripherals such as the State Configurable Timer (SCT)and the Serial General Purpose I/O (SGPIO) interface, two High-speed USB controllers,Ethernet, LCD, an external memory controller, and multiple digital and analog peripherals
ass="tags">标签： 4300 LPC ARM 双核微控制器
ass="time">上传时间： 2013-10-28
ass="username">上传用户：15501536189
The NXP LPC315x combine an 180 MHz ARM926EJ-S CPU core, High-speed USB 2.0OTG, 192 KB SRAM, NAND flash controller, flexible external bus interface, an integratedaudio codec, Li-ion charger, Real-Time Clock (RTC), and a myriad of serial and parallelinterfaces in a single chip targeted at consumer, industrial, medical, and communicationmarkets. To optimize system power consumption, the LPC315x have multiple powerdomains and a very flexible Clock Generation Unit (CGU) that provides dynamic clockgating and scaling.The LPC315x is implemented as multi-chip module with two side-by-side dies, one fordigital fuctions and one for analog functions, which include a Power Supply Unit (PSU),audio codec, RTC, and Li-ion battery charger.
ass="tags">标签： 315x LPC 315 ARM
ass="time">上传时间： 2014-01-17
ass="username">上传用户：Altman
本软件是关于MAX338, MAX339的英文数据手册：MAX338, MAX339 8通道/双4通道、低泄漏、CMOS模拟多路复用器 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.
ass="time">上传时间： 2013-11-12
ass="username">上传用户：18711024007
Today in many applications such as network switches, routers, multi-computers,and processor-memory interfaces, the ability to integrate hundreds of multi-gigabit I/Os is desired to make better use of the rapidly advancing IC technology.
ass="time">上传时间： 2013-10-30
ass="username">上传用户：ysjing
This book evolved over the past ten years from a set of lecture notes developed while teaching the undergraduate Algorithms course at Berkeley and U.C. San Diego. Our way of teaching this course evolved tremendously over these years in a number of directions, partly to address our students' background (undeveloped formal skills outside of programming), and partly to reect the maturing of the eld in general, as we have come to see it. The notes increasingly crystallized into a narrative, and we progressively structured the course to emphasize the story line implicit in the progression of the material. as a result, the topics were carefully selected and clustered. No attempt was made to be encyclopedic, and this freed us to include topics traditionally de-emphasized or omitted from most Algorithms books.
ass="tags">标签： Algorithms 算法
ass="time">上传时间： 2013-11-11
ass="username">上传用户：JamesB
