Broadband MIMO Antenna System for 5G Operations in Mobile Phones

A broadband 8‐antenna multiple‐input and multiple‐output (MIMO) system working for 5G new radio N77 (3.3‐4.2 GHz) in mobile terminals is proposed. In particular, each antenna element/unit consists of a monopole‐type meandered branch and an inverted U‐shaped self‐isolated antenna branch; and the antenna unit is fed by the meandered branch. The antenna unit has two resonances generated separately by each branch of the antenna unit. Since the monopole couples strongly with the self‐isolated antenna element that has the inherent self‐isolation characteristics, quite good isolation for the broadband 8‐antenna MIMO system can be obtained. The results such as antenna efficiency, radiation patterns, envelope correlation coefficient, and channel capacity are also presented.     

串口通信在CAD/CAM系统中的设计与实现

串行口通信是终端与计算机或计算机之间进行数据通信的一种方式，在工业上发挥着重要的作用。具有传输距离远、传输稳定、简单实用等特点。论述了在三维造型软件平台上(JHSolid)的CAM模块中串口通讯的实现。应用VisuaI C 结合CSem aJPort类实现自动侦测串口、在数控机床与PC之间进行数据及文件的传输等功能，并讨论该系统的基本原理和具体实现。     

Efficient visual communication channels

This paper compares the efficiency of uniform quantization in the spatial domain with frequency dependent quantization in the spatial frequency domain, in the context of the end-to-end performance of visual-communication channels. Results show that the minimum data density required for informationally lossless transmission depends on the design of the image-gathering device. The information in the acquired signal, not the energy, dictates the trade-off between data transmission and visual quality. Frequency dependent quantization that maintains the information capacity of the channel while reducing the entropy of the encoded signal, improves its information efficiency. Information bit-allocation is preferable for optimized visual communication for restoration, whereas energy bit-allocation can be used only for image reconstruction.This research was supported by NASA Task Assignment NAS1-18584-90 with the Department of Mathematics, Old Dominion University, Norfolk, Virginia 23529.     

卫星通信地球站UPS的选型指南

本文针对卫星地球站配备UPS的需要,比较了不同种类UPS的性能特点,提出了推荐选择标准在线式UPS的理由,并给出了具体选择UPS的二十个要点,可以作为UPS的选型指南。     

湖北电力调度软交换容灾备用系统建设研究

针对“省为地备、地为县备”的容灾建设机制,文章在分析湖北电力通信调度系统现状的基础上。对通信网络容灾中采用软交换方式建设全省的调度电话备用系统展开讨论。通过建立调度软交换备用系统这种方式来满足容灾机制要求,提高调度交换系统网络安全性,扩展调度通信系统业务新模式。     

直流输电线路故障对电信线路感应的计算

直流输电线路对电信线路的危险影响、影响机理和计算方法,国内外资料及文献中尚无系统的介绍,我国也尚无统一的计算、设计标准。为便于工程设计,可以采用理论计算与实测对比相结合的方法推导出的简化公式进行计算。     

基于COLDFIRE MCF5270电力通讯管理机的设计

介绍一种基于飞思卡尔MCF5270单片机的电力通讯管理机的设计,同时介绍了其硬件设计和软件设计方案．通过配置软件可方便地配置其所有通讯端口的协议、通讯参数等设置,并可进行远程维护调试。     

火电厂电气监控系统间隔层通信的现状与发展

对火电厂电气监控系统间隔层设备的通信接口方式及通信协议进行了介绍,并指出了其特点及发展方向。     

电力线通信(PLC)技术综述

论述了电力线通信技术概况、技术分类、功能定位、主要用途、网络体系结构特征、发展动态、标准化进展、EMC问题等，侧重于宏观分析，不涉及技术细节。     

White broadband power line communication: Exploiting the TVWS for indoor multimedia smart grid applications

Balancing the energy production and consumption in smart grids influences the integration of new high‐speed communication technologies, to support monitoring services. Sharing the television white space (TVWS) spectrum between licensed and unlicensed users has been recommended by the federal communications commission in 2004. Federal communications commission allows the unlicensed users to access both the very high frequency (VHF) and the ultra‐high frequency channels in TVWS. On the other hand, broadband power line communication (BPLC) has drawn the researchers' attention over the last decade as a high‐speed indoor communication technology. One application for BPLC is the multimedia service in smart grid applications. In this article, we present an overview of the standards, regulations, and channel models of the TVWS and BPLC as 2 separate technologies. We then propose the deployment of the BPLC technology in the TVWS VHF band to build up the white BPLC (WBPLC) communication systems. The WBPLC incorporates the TVWS and the BPLC technologies into multiple‐input multiple‐output communication systems in the VHF band. The simulation results show significant throughput enhancement in the WBPLC over both the TVWS and BPLC communication systems, indicating that WBPLC can be a promising technology to serve the growing needs for the multimedia services in future smart grids.