无线/水声通信浮标技术研究及其实现

本文研究并设计实现了一种用于浅海水声信道多速率通信的无线/水声通信(racom)浮标,介绍了其水声通信和无线通信技术方案和工程设计与实现。本文设计的浮标综合了水声通信、DSP信号处理和无线电通信等技术,也可以用作水声通信/传感网络中的无线/水声通信(racom)网关节点。海上试验验证了本浮标总体设计方案的可行性。海上试验中,浮标无线通信距离达到15.2 km,误码率不大于10 6;除2 kbps速率外,浮标各种速率的水声通信数据传输误码率都小于1%,最大通信作用距离达到9.6 km;同时,试验也验证了浮标与水下运动平台之间的通信功能。     

基于73K222AU芯片实现单片机远程通信

远距离数据采集与传输主要依赖于公共有线或无线网络,数据交换和远程控制容易泄露信息,不利于重要数据有效保护。为了实现专用线路远程通信,有效解决长距离数据传输困难,提出基于调制解调器73K222AU芯片与单片机AT89S52 、变压器HR219307的硬件电路和接口电路设计方法,达到数据和信号远程交换;通信校验采用CRC循环冗余码校验算法与奇偶校验算法,不仅简化了运算,同时有效解决传输误码影响;程序设计采用结构清晰的C51语言,还具有汇编语言的硬件操作能力。实验结果显示,采用73K222AU芯片设计的电路,能够实现单片机远程通信,数据传输距离远、可靠性高、通信组网方便、环境适应能力强,满足野外专用数据通信组网。     

Analytical derivation of the impulse response for the bounded 2-D diffusion channel

This letter focuses on the derivation of the hitting probabilities of diffusing particles absorbed by an agent in a bounded environment. In particular, we analogously consider the impulse response of a molecular communication channel in a 2-D and 3-D environment. In 2-D, the channel involves a point transmitter that releases molecules to a circular absorbing receiver that absorbs incoming molecules in an environment surrounded by a circular reflecting boundary. Considering this setup, the joint distribution of the molecules on the circular absorbing receiver with respect to time and angle is derived. Using this distribution, the channel characteristics are examined. Then, we extend this channel model to 3-D using a cylindrical receiver and investigate the channel properties. We also propose how to obtain an analytic estimate for the unbounded 2-D channel from our derived solutions, as no analytic derivation for this channel is present in the literature. Throughout the letter, we perform particle-based simulations to compare the analytic results and lay evidence for our findings.     

ITER GIS实验平台控制系统

介绍了以GE PLC为控制核心的分布式送气实验平台控制和测量系统的设计与实现。系统采用了工业以太网、CAN总线、RS485等多种通讯技术,实现了对ITER GIS设备的安全运行控制、远程操作控制及各设备运行状态的实时监测。     

Effective Bandwidths and Performance Bounds in High-Speed Communication Systems

This paper is concerned with quality of service guarantees in an environment with bursty traffic streams, such as those in the emerging ATM-based broadband ISDN.⁴ For virtually any traffic stream, new performance bounds are obtained in terms of effective bandwidths and burstiness constraints. The new bounds are tighter than those previously available and are asymptotically achievable, potentially resulting in better performance when used in traffic management. Various performance measures are considered. It is shown that the effective bandwidth of a departing traffic is bounded by that of the incoming traffic. For traffic streams having independent increments and Markov-modulated processes, the bounds are further refined to a point close to the exact values in some cases. Computationally, evaluation of the bounds requires less effort than finding effective bandwidths and burstiness constraints. Finally, the bounds are applied to routing control to find the near-optimal probabilistic routing policy.     

专用以太网络通讯软件-BRUKNET

本文介绍BRUKER公司研制的专用以太网通讯软件-BRUKNET。该软件用于ASPECT 2000/3000计算机与以太网上其它计算机之间的高速数据通讯。     

光纤通信中的光学复用技术

本文介绍光通信中光学复用技术的发展现状,重点介绍了光学波长复用和光学时间复用在高速传输系统中的最新发展。     

Suppression of dynamic instability and comparison of the response time in mutually pumped phase conjugators

The origin and the suppression of dynamic instability have been experimentally studied in mutually pumped phase conjugators when the two input beams are coherent. Experimental results show that the dynamic instability of the phase conjugation outputs arises from the competition among backscattering gratings, reflection gratings, and shared transmission gratings. The effect of the competition on the coupling channel is also presented. A simple method, the slight vibration of the experimental table is proposed. It can eliminate the dynamic instability. The response time is measured and fit for several kinds of discovered mutually pumped phase conjugators. We find that the bird-wing and sickle mutually pumped phase conjugators, which have one internal reflection, have a shorter response time. A possible explanation is suggested.