Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
上传时间： 2013-10-23
上传用户：685
Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
标签： 无线技术
上传时间： 2013-10-08
上传用户：kinochen
Abstract: This article describes the Antenna Interface Standards Group (AISG) standard in telecommunications and details itshardware implementation. It explains how a fully integrated transceiver such as the MAX9947 can help reduce space and cost, andsolve bus arbitrations in base-station tower equipment.
上传时间： 2014-12-30
上传用户：wangchong
在研究传统家用燃气报警器的基础上，以ZigBee协议为平台，构建mesh网状网络实现网络化的智能语音报警系统。由于传感器本身的温度和实际环境温度的影响，传感器标定后采用软件补偿方法。为了减少系统费用，前端节点采用半功能节点设备，路由器和协调器采用全功能节点设备，构建mesh网络所形成的家庭内部报警系统，通过通用的电话接口连接到外部的公用电话网络，启动语音模块进行报警。实验结果表明，在2.4 GHz频率下传输，有墙等障碍物的情况下，节点的传输距离大约为35 m，能够满足家庭需要，且系统工作稳定，但在功耗方面仍需进一步改善。 Abstract: On the basis of studying traditional household gas alarm system, this paper proposed the platform for the ZigBee protocol，and constructed mesh network to achieve network-based intelligent voice alarm system. Because of the sensor temperature and the actual environment temperature, this system design used software compensation after calibrating sensor. In order to reduce system cost, semi-functional node devices were used as front-end node, however, full-function devices were used as routers and coordinator，constructed alarm system within the family by building mesh network，connected to the external public telephone network through the common telephone interface, started the voice alarm module. The results indicate that nodes transmit about 35m in the distance in case of walls and other obstacles by 2.4GHz frequency transmission, this is able to meet family needs and work steadily, but still needs further improvement in power consumption.
上传时间： 2013-10-30
上传用户：swaylong
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.
上传时间： 2013-10-09
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.
上传时间： 2014-03-25
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:
标签： S参数
上传时间： 2013-12-19
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.
上传时间： 2013-11-13
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.
上传时间： 2014-12-31
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
上传时间： 2013-10-28
上传用户：15501536189
