基于DTMF的智能电话控制器设计

介绍了一种以单片机AT89S52和双音多频解码集成电路MT8870为核心,通过电话线路遥控的远程智能控制器的设计。系统通过铃流检测,DTMF信号解调等,实现自动摘机,并且实现了密码校验、修改,系统标识,次数限制等功能。本文对该控制器的工作原理、硬件配置、软件设计、功能进行了详细论述,经样机调试试验证明,其各项功能完成良好,具有较高的实用价值。     

单片微处理器AT89C51在时隙交换和控制中的应用

MT8980是Mitel公司生产的PCM时分复用时间交换器,文中分析了它的原理及时序关系,给出了AT89C51与MT8980的接口电路及控制软件程序,最后对其典型应用进行了说明。     

数字交换芯片MT90826及其应用

MT90826芯片是MITEL公司生产的大容量数字交换器件，单片可实现4096×4096通道的无阻塞交换，可编程建立在每一个通道基础上、附带不同通过延时的时隙交换，利用该器件的组合可构成更大容量的交换网络或交叉连接矩阵。该器件可有效解决传统交换机采用多个存储器及控制集成电路所构成的交换网络系统存在的生产成本高、调试困难、稳定性差等问题。文章介绍了MT90826芯片的内部结构、原理及时序关系，并给出了控制软件设计，其编程思路可拓展到MITEL公司同系列的其他数字交换芯片。     

Investigation of mercury metallothionein complexes in tissues of rat after oral intake of HgCl2

Mercury, a highly toxic metal found widely throughout the environment, is a potent inducer of metallothionein (MT) expression. The role of MTs in the detoxification of mercury after its oral intake in mammals is studied. After feeding rats with mercuric chloride by gastric gavage, the distribution of heavy metals in rat tissues was investigated by inductively coupled plasma mass spectrometry (ICP‐MS). Extensive accumulation of mercury, copper and zinc in kidney and liver is observed. A homemade preparative size‐exclusion chromatography (SEC) column (30 cm × 1.9 cm) packed with Sephadex G‐75 (40–120 µm particle size) gel (Pharmacia) was used for the purification of MT fractions in rat tissues. Preliminary results from SEC indicate that the mercury‐binding MT levels in liver were much lower than in kidney. The MT fractions were collected, desalted, and then separated by reversed‐phase high‐performance liquid chromatography (HPLC) with UV–Vis spectrometry, ICP‐MS and electrospray ionization MS detection. One major and several minor peaks were observed in the HPLC chromatograms of the MT fraction for the kidney sample. UV absorption spectra indicate that MTs were found to bind with mercury. There were no significant mercury‐binding MTs detected in the liver sample using UV detection. ICP‐MS detection showed that mercury‐binding MTs in kidney contained large amounts of mercury and copper but little zinc. Further characterization with ESI‐MS showed that the major peak found in kidney contained Hg₆Cu, Hg₅Cu₂‐MT‐2c and Hg₆‐MT‐2β, Hg₆Cu‐MT‐1γ, Hg₇‐MT‐2α. However, distinction between copper and zinc could not be made based on current mass spectrometric analysis because of instrumental resolution limitations. Copyright © 2005 John Wiley & Sons, Ltd.     

HDLC协议处理芯片MT8952B在数字程控交换机中的应用

在目前数字程控交换机或网络设计中，普遍采用HDLC高级数据链路控制协议，MT8952B是Mitel公司生产的HDLC协议处理器芯片，本文介绍了它的原理及在内部时钟模式下的时序关系，并给出了单片机与MT8952B的接口电路及信令消息读写程序，对其在数字程控交换机中的应用进行了说明。     

国际短信拦截系统实现方案分析

本文阐述了国际短信的正常发送流程,分析了国际短信拦截系统的应用场景,并结合目前国际短信拦截系统已有的判别机制,深入的分析了各网元的详细判别过程。通过本文能够更深入的了解国际短信拦截系统的实现方案,为今后类似工程的建设拓展思路。     

Optimal resource scheduling algorithm for cell boundaries users in heterogenous 5G networks

Deployment of small cells over the existing cellular network is an effective solution to improve the system coverage and throughput of fifth generation (5G) mobile communication networks. The arrival of the 5G mobile networks have demonstrated the importance of advanced scheduling techniques to manage the limited frequency spectrum available while achieving 5G transmission requirements. Cellular networks of the future necessitate the formulation of efficient resource allocation schemes that mitigate the interference between the different cells. In this research work, we formulate an optimization problem for heterogenous networks (HetNets) for resource allocation to maximize the system throughput among the cell center users (CCUs) and cell edge users (CEUs). We solve the optimization problem by effective utilization of the weight factors distribution for resource allocation. A novel Utility-based Resource Scheduling Algorithm (URSA) optimizes the resource sharing among the users with better delay budget of each application. The designed URSA ameliorates fairness along with reduced cross layer interference for real and non-real time applications. Performance of the URSA has been evaluated and compared most relevant state of art algorithms using the matlab based simulators. Furthermore, simulation results validate the superiority of the proposed scheduling scheme against conventional techniques in terms of throughput, fairness, and spectral efficiency.     

基于物联网RFID智能化仓库系统设计

针对仓库管理的智能化应用需求,研究基于RFID技术的智能化仓库管理。文中介绍了智能化仓库管理系统的硬件结构、功能模块、软件架构以及系统的出入库作业流程。该应用设计能够有效提高仓库的运转效率,并降低了企业的仓库管理成本。     

数字电视区域控制的实现

地区间经济状况和消费水平的差异导致运营策略和收费标准的不同,使区域控制在数字电视运营中扮演了重要角色。本文介绍了区域控制的概念、原理,以及5种不同技术的解决方案,并对通过IC卡实现区域控制方案的测试情况作了简要说明。     

基于MT9075芯片的PCM线路测试仪的设计

针对G．703E1传输线路的检测与维护,利用MT9075芯片的失步告警、PCM传输、CAS、CCS信令处理等功能,设计了由89S52单片机控制的PCM线路测试仪。该测试仪可根据串口信令或DIP开关设置实现对PCM线路状态监测、线路话音监听与插人、线路信令分析等功能,且具有易于操作、性价比高等特点。