Out of band signalling technique for passive optical networks

In this communication we present a novel means of signalling between an out-of-service RT and the CO when connected via a passive optical network which contains other RTs in-service using a TDMA protocol. A simple experiment using a non-coherent receiver is used to demonstrate the technique.     

JSP中的定制标记库介绍

JavaServer Pages技术是用于开发Web应用的优秀体系结构，对于Web开发人员起着至关重要的作用，但他最重要的技术之一——定制标记库(Custom Tag Library)却常常未被充分利用，本文对定制标记库进行了详细的介绍。     

Passive optical networks for local telephony and cable TV provision

Recent proposals have been made for a passive optical local access network (PON) for telephony and cable TV applications. These are leading to the design of new telecommunications customer access equipment whose functional requirements are discussed, together with details of the system demonstrators at BTRL. Possible sccenarios for network deployment are presented.     

波长共享的WDM无源光网络

提出了波长共享的WDM无源光网络的系统结构及其媒质接入协议.这种方案结合了波长路由和功率分割,控制信道采用随机接入,并使用先到先服务的调度策略有效地分配上行带宽.分析了系统中的分组延时,数值计算表明系统具有良好的延时特性.     

Integrated design of piezoelectric damping system for flexible structure

This paper aims at developing an integrated design method of the active/passive hybrid type of piezoelectric damping system for reducing the dynamic response of the flexible structures due to external dynamic loads. The design method is based on the numerical optimization technique whose objective function is a control effort of the active damping. A vibration suppression performance, which is evaluated by the maximum value of the gain of the frequency response function of the structure, is constrained. In order to demonstrate the structural damping capability of the hybrid type of piezoelectric damping system designed by proposed method, numerical simulation and laboratory experiment will be done using a three-story flexible structure model equipped with 12 surface bonded PZT tiles pairs. Both numerical and experimental results indicate that the optimally designed hybrid piezoelectric damping system can be successfully achieving excellent performance as compared to a conventional purely active piezoelectric damping system.     

一种无源UHF RFID电子标签验证开发平台

提出了一种符合ISO/IEC 18000-6B标准的无源UHF RFID电子标签验证开发平台,其工作在915MHz ISM频带下.该平台有效减少了设计开发时间及成本,并实现了电子标签的快速原型设计.该平台包括RFID模拟前端以及采用Altera ACEX FPGA实现的标签控制逻辑.RFID模拟前端采用Chartered 0.35μm 2P4M CMOS工艺进行流片,包括本地振荡器、时钟产生电路、复位电路、匹配网络和反向散射电路、整流器、稳压器以及AM解调器等,通过调整FPGA中的标签控制逻辑,该平台实现了快速、灵活而高效的RFID验证开发.     

Employing injection-locked Fabry–Perot laser diodes to improve bidirectional WDM–PON performances

We proposed and demonstrated a bidirectional wavelength-division-multiplexing (WDM)–passive optical network (PON) employing injection-locked Fabry–Perot laser diodes (FP LDs) at both transmitting sites, and adaptive filters at both receiving sites. Injection-locked FP LDs, a particularly inexpensive option, are used to replace the conventional distributed feedback (DFB) LDs in WDM–PON. Adaptive filters are attractive because they can track the variations and compensate the nonlinear distortions. Transmission performance over 20 km of a standard single-mode fiber (SMF) was investigated. Improved performance of bit error rate (BER), better and clear eye diagram were achieved in our proposed WDM–PON.     

一种用于无源射频识别标签的上电复位电路

提出了一种新型的低压低功耗上电复位电路。该电路利用MOS管多种二级效应,采用多种低压低功耗技术,满足降低功耗的需要。整个上电复位电路的静态功耗低于1μW,应用于1.8 V与1.2 V电源电压。设计采用SMIC 0.18μm EEPROM工艺,可应用于其他低电源电压以及低功耗要求的芯片设计。     

RFID技术与集装箱追踪管理

本文分四部分介绍了RFID在集装箱物流方面的应用。第一部分描述了全球集装箱物流的现状,分析了当今集装箱运输中存在的问题,指出集装箱物流过程的信息化水平是制约集装箱运输发展的瓶颈之一;第二部分重点介绍了集装箱运输的安全问题以及国内外对此采取的相关的措施,说明了国际贸易便利与安全对RFID技术的需求;第三部分详细阐述了国内外对集装箱RFID技术的研究进展及其产品在集装箱运输中的应用情况;最后通过介绍国外RFID技术在集装箱运输中的应用情况展望了RFID技术在集装箱管理应用中的发展前景。     

手持式声表面波射频识别系统

针对脉冲时延结合相位编码的声表面波标签,设计了相应的射频识别系统,阅读器接收链路采用零中频正交解调方案。实际制作了编码容量接近300万的标签和采用4层印制电路板(PCB)结构的小型化阅读器硬件电路。通过对硬件电路、陶瓷天线、液晶屏的一体化布局,搭建了一款手持式声表面波射频识别系统,并测试了阅读器的发射、接收链路及陶瓷天线的回波损耗。手持式系统的识别距离可达50 cm,液晶屏不仅能显示识别结果,还能显示图像信息以实时调试系统。