Study of LMDS Videoconferencing System

LMDS is one kind of fixed broadband wireless access network. It uses radio spectrum between 10GHz and 40GHz to transmit voice, video, and data signals within small cell 3-10 miles in diameter. This paper proposes some key technical scenarios to support videoconferencing services transported on LMDS. Firstly, two kinds of typical LMDS lower layer standards made by DAVIC and 802.16 separately are discussed from the angle of supporting video conferencing services. Then, H.323 is studied and recommended as the standard of LMDS video conferencing system. And some strategies are proposed to support H.323 services on LMDS. After that, IP multicast technology, the key supporting technology of H.323, is studied from the angle of running on LMDS. Scenarios for IGMP, RMTP protocol running on LMDS are suggested and analyzed with Markov network queuing theory. The technical scenarios proposed by this paper make use of the transporting property of LMDS to support LMDS videoconferencing system more effectively.     

Cost-Effective Migration from Sub-Lambda to Wavelength-Based Metro Networks

This article will discuss the importance of hybrid coexistence of sub-lambda grooming with wavelength-based services for driving down costs and maximizing the use of metro bandwidth, as well as enabling next-generation lambda-based services. The article will also address migration to all optical metro networks.     

TCP/IP协议中ARP模块的研究及分析

以PING程序的实现为线索，详细、深入地研究了TCP／IP协议中ARP模块的工作原理及实现机制分析了TCP／IP运行过程中容易被忽略的ARP模块中的相关问题，并提出了若干改进建议．     

基于单片机的USB控制技术在远程数据采集中的应用

针对中小旅店信息管理对远程数据采集的需求,本公司研究开发了基于单片机的USB控制技术完成对扫描仪的控制.应用结果表明该技术性能优越、稳定,能满足客户需求.     

TMS320F206 DSP的以太网接口设计

介绍以太网控制器RTL8019AS的主要特点，给出了利用RTL8019AS实现TMS320F206 DSP与以太网互连的接口电路，接口方式为跳线模式，通过该接口可实现DSP与以太局域间网的连接。     

Cost-Effective Migration from Sub-Lambda to Wavelength-Based Metro Networks

This article will discuss the importance of hybrid coexistence of sub-lambda grooming with wavelength-based services for driving down costs and maximizing the use of metro bandwidth, as well as enabling next-generation lambda-based services. The article will also address migration to all optical metro networks.     

基于TCP/IP协议的电源监控系统

为完成以太网中对电源实施控制和实时监测,以AT89C2051单片机为控制核心,由C2000S-NET完成通信协议处理,研制了一种远程电源控制器,给出了基于TCP/IP(Transmission Control Protocol/Internet Protocol)协议的电源监控系统的设计与实现.通过该控制器可组成基于TCP/IP协议的以太网监控系统,达到异地监控电源的目的.实践证明,该监控系统性能稳定可靠,完全能满足实际需要.     

S7路由功能在轧管机控制系统中的应用

多种控制网络同时存在于同一自动化控制系统中已经非常普遍,如何在不同网络之间实现数据路由,显得尤其重要。介绍了轧管机控制系统的组成、对网络路由功能的需求以及在项目中如何实现路由。项目实现了通过S7-300PLC从Ethernet(工业以太网)网络到Profibus-DP网络的路由,并完成了工程师站对变频器站参数的读取和修改。     

基于DSP/BIOS的以太网通信接口程序设计

通过对嵌入式实时操作系统DSP/BIOS的分析介绍,针对其特点和优点,给出了在DSP/BIOS下以太网通信接口程序的建立步骤、配置方法及执行过程。与传统软件开发比较,基于DSP/BIOS的程序开发具有易于调试和维护的特点,缩短了开发时间,增加了代码的兼容性、继承性和可移植性。     

基于ARM11的矿用大容量组合开关控制系统的设计

设计了一种基于ARM11的矿用组合开关控制系统,该控制系统基于嵌入式技术和工业以太网技术,可实现井下开关运行监控、故障保护、网络通信、运行参数及状态显示等功能。文中给出了系统软件、硬件结构及工作方式的实际方案并详细介绍了系统软件和上位机管理系统的设计方法。试运行结果表明,该系统稳定可靠,可满足矿用组合开关的控制要求。