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RADIO

无线电广播是以无线电波为传输广播节目载体的广播方式。世界公认的首次电台播音是1920年11月2日美国威斯汀豪斯公司在匹茨堡的KDKA电台播出哈定当选总统。此后,苏联、英国以及中国等许多国家纷纷建立了广播电台。
  • 双绞线和低通滤波器降低EMI_RFI

    Abstract: Alexander Graham Bell patented twisted pair wires in 1881. We still use them today because they work so well. In addition we have the advantage ofincredible computer power within our world. Circuit simulators and filter design programs are available for little or no cost. We combine the twisted pair and lowpassfilters to produce spectacular rejection of RADIO frequency interference (RFI) and electromagnetic interference (EMI). We also illustrate use of a precision resistorarray to produce a customizable differential amplifier. The precision resistors set the gain and common mode rejection ratios, while we choose the frequencyresponse.

    标签: EMI_RFI 双绞线 低通滤波器

    上传时间: 2014-11-26

    上传用户:Vici

  • LFRD003水表自动抄表(AMR)的参考设计

    Abstract: This reference design provides a complete demonstration platform for using industrial/scientific/medical RADIO frequency

    标签: LFRD 003 AMR 水表

    上传时间: 2013-11-09

    上传用户:LP06

  • 用于汽车无线电和信息娱乐系统的8V开关电源

    Abstract: This application note illustrates an intermediate 8V switching power supply for an automotive RADIO and infotainment system.The design withstands the complete automotive input voltage range (including cold crank and load dump conditions), assuring a stable8V supply for common subsystems such as a CD driver, LCDs, and a RADIO module in modern infotainment systems. To avoiddisturbance in the AM and FM bands, the switching power supply runs at a fixed frequency of 2MHz, enabling an ideal solution forRADIO systems.

    标签: 汽车无线电 信息娱乐系统 开关电源

    上传时间: 2013-11-20

    上传用户:feitian920

  • 优化输电线路 精确测量电压驻波比(VSWR)

    Abstract: Impedance mismatches in a RADIO-frequency (RF) electrical transmission line cause power loss andreflected energy. Voltage standing wave ratio (VSWR) is a way to measure transmission line imperfections. Thistutorial defines VSWR and explains how it is calculated. Finally, an antenna VSWR monitoring system is shown.

    标签: VSWR 输电线路 精确测量 电压驻波比

    上传时间: 2013-10-19

    上传用户:yuanwenjiao

  • 基于51单片机的无线识别装置系统

    介绍一种简单射频识别系统设计。该设计包括阅读器、应答器和线圈3部分。由单片机控制阅读器向应答器发射无线信号,并接收应答器回送的信号,再通过分析回送信号识别物品。阅读器和应答器之间以半双工通信方式通信。 Abstract:  A simple design of RADIO frequency identification system is given in this paper.The design includes reader,responder and winding.Through MCU,signals are sent to responder from reader,then corresponding signals are sent back. According to the analysis of the signals sent back,the objects can be identified.Half-duplex communication is adopted? between? reader? and? responder.

    标签: 51单片机 无线识别 装置

    上传时间: 2013-10-11

    上传用户:plsee

  • MT8870D DTMF解码芯片

    Features• Complete DTMF Receiver• Low power consumption• Internal gain setting amplifier• Adjustable guard time• Central office quality• Power-down mode• Inhibit mode• Backward compatible withMT8870C/MT8870C-1Applications• Receiver system for British Telecom (BT) orCEPT Spec (MT8870D-1)• Paging systems• Repeater systems/mobile RADIO• Credit card systems• Remote control• Personal computers• Telephone answering machine

    标签: 8870D 8870 DTMF MT

    上传时间: 2013-11-20

    上传用户:mpquest

  • Microchip ZigBee协议栈

    Microchip ZigBee协议栈:ZigBee™ 是专为低速率传感器和控制网络设计的无线网络协议。有许多应用可从ZigBee 协议受益,其中可能的一些应用有:建筑自动化网络、住宅安防系统、工业控制网络、远程抄表以及PC 外设。与其他无线协议相比, ZigBee 无线协议提供了低复杂性、缩减的资源要求,最重要的是它提供了一组标准的规范。它还提供了三个工作频带,以及一些网络配置和可选的安全功能。如果您正在寻求现有的控制网络技术(例如RS-422、RS-485)或专有无线协议的替代方案, ZigBee 协议可能是您所需的解决方案。此应用笔记旨在帮助您在应用中采用ZigBee 协议。 可以使用在应用笔记中提供的Microchip ZigBee 协议栈快速地构建应用。为了说明该协议栈的用法,本文包含了两个有效的演示应用程序。可将这两个演示程序作为参考或者根据您的需求经过简单修改来采用它们。此应用笔记中提供的协议栈函数库实现了一个与物理层无关的应用程序接口。 因此,无需做重大修改就可以轻松地在射频(RADIO Frequency,RF)收发器之间移植应用程序。在此文档末尾的“常见问题解答”中提供了有关Microchip 协议栈和用法的一些常见问题及其答案。

    标签: Microchip ZigBee 协议栈

    上传时间: 2013-10-08

    上传用户:u789u789u789

  • Employing a Single-Chip Transceiver in Femtocell Base-Station Applications

    Abstract: This application note discusses the development and deployment of 3G cellular femtocell base stations. The technicalchallenges for last-mile residential connectivity and adding system capacity in dense urban environments are discussed, with 3Gfemtocell base stations as a cost-effective solution. Maxim's 3GPP TS25.104-compliant transceiver solution is presented along withcomplete RADIO reference designs such as RD2550. For more information on the RD2550, see reference design 5364, "FemtocellRADIO Reference Designs Using the MAX2550–MAX2553 Transceivers."

    标签: Base-Station Applications Single-Chip Transceiver

    上传时间: 2013-11-07

    上传用户:songrui

  • 基于SCT3918的CDMR数字对讲机设计

    为了响应国家工业和信心产业部[2009]666号文件我国数字对讲机实现模拟转数字化的要求,并且为了方便企业生产和调试、降低成本的目的。采用国产基带芯片SCT3918设计了一款适应我国国情的数字对讲机CDMR(China Digital Mobile RADIO),在实验室内做了射频技术指标测试、音频技术指标测试、可靠性测试,实验结果表明射频技术指标符合[2009]666号文件要求,音频技术指标符合《移动通信调频无线电话机通用技术条件》,设计符合我国对讲机模拟转数字的政策、适合我国的国情、便于企业生产和调试。

    标签: 3918 CDMR SCT 数字对讲机

    上传时间: 2013-10-18

    上传用户:caozhizhi

  • ISM射频接收器的基带计算

    Abstract: Many industrial/scientific/medical (ISM) band RADIO frequency (RF) receivers use an external Sallen-Key datafilter and a data slicer to generate the baseband digital output. This tutorial describes the ISM-RF Baseband Calculator,which can be used to calculate the filter capacitor values and the data slicer RC components, while providing a visualexample of the baseband signals.

    标签: ISM 射频接收器 基带计算

    上传时间: 2013-11-04

    上传用户:jkhjkh1982