一种双U形槽加载的新型三频平面倒F天线

提出一种新型的三频平面倒F天线结构。通过在矩形贴片上开双U形槽,非常容易获得三频特性,而且可以很方便地实现对三个谐振频率的单独调节。文中设计了一个工作在GSM/DCS/ISM三个频段的平面倒F天线,采用基于矩量法的IE3D软件进行建模、仿真和分析,实测结果与仿真结果相当吻合。此外,由于这种天线只用一个同轴探针馈电,尺寸小并且结构简单,因而容易设计、制作和调节。     

G2一RTI中间件的研究与实现

简述了当前高层结构体系HLA的显著特点,介绍了如何利用G2构建实时智能系统。利用HLA架构在分布式系统设计中可扩展、可重用的特点,结合G2的实时性、高的开发效率以及与能够与各种外部软、硬件系统进行数据通讯和互操作性等,开发了一个G2与HLA分布式仿真系统互连的标准接口程序,可以有效地解决分布式仿真系统中实时性差以及开发效率低的问题,对构建大型仿真系统大有裨益。     

CDMA2000反向业务信道的MATLAB仿真与实现

文章基于Windows平台,使用Matlab中的软件包Simulink对CDMA2000移动通信系统的反向业务信道进行了仿真,主要是对"CDMA2000移动台发射机"进行了基于时间流的仿真与实现.分析了信号在"CDMA2000移动台发射机"的主要处理流程,包括信源编码,信道编码,数据调制,以及基带滤波等过程.     

Pseudo Random Number Generator Based on Back Propagation Neural Network

Random numbers play an increasingly important role in secure wire and wireless communication. Thus the design quality of random number generator（RNG） is significant in information security. A novel pseudo RNG is proposed for improving the security of network communication. The back propagation neural network（BPNN） is nonlinear, which can be used to improve the traditional RNG. The novel pseudo RNG is based on BPNN techniques. The result of test suites standardized by the U.S shows that theRNGcan satisfy the security of communication.     

I^2C串行总线存储技术在单片机系统中的应用

介绍I^2C串行总线原理及AT24CXX系列串行EEPROM的特点。着重阐述了利用I^2C串行总线和AT24CXX系列串行EEPROM实现数据存储的技术，并给出了该技术在MCS51系列单片机系统中的实现方法。     

反馈联合检测算法性能上限研究

反馈联合检测算法通常可为迫零数据块判决反馈均衡器(ZF-BDFE)和最小均方差数据块判决反馈均衡器(MMSE-BDFE)算法。本文研究了反馈联合检测算法性能及其上限,提出了算法性能上限的分析结构。研究表明,MMSE- BDFE算法性能优于ZF-BDFE；ZF-BDFE和MMSE-BDFE分别与各自算法性能上限之间相差均不会超过0．5dB。反馈联合检测算法可以满足实际通信系统的要求,应用前景良好。     

Equilateral-Triangle-Resonator Injection Lasers With Directional Emission

Equilateral-triangle-resonator (ETR) lasers with an output waveguide jointed at one vertex of the resonator are fabricated on (100) GaInAsP-InP wafers using photolithography and a two-step inductively coupled plasma (ICP) etching technique. Distinct peaks with the mode spacing of longitudinal mode intervals are observed in the luminescence spectra at room temperature. Furthermore, some minor peaks appear in the middle of the main peaks, which can be attributed to the first-order transverse modes as predicted in the theoretical results. CW directional lasing emissions are achieved for ETR lasers with side lengths ranging from 15 to 30 mum up to 200 K. The temperature dependences of the threshold current and lasing wavelength are measured for an ETR laser with the side length of 20 mum from 80 to 200 K. The observed threshold current rapidly increases as temperature increases over 170 K     

一种高速移动数据突发通信中的频偏纠正方法

本文主要针对具有通信终端的运动速率很大、移动速率变化不规律特点的特殊突发数据通信系统的实现进行研究，提出了一种能够快速捕获频偏，并且进行突发数据的有效解算的方法。这种方法需要采用差分相位调制方式，并且应用很短的前导序列进行频偏估计，然后利用估计得到的频偏对突发包内的数据进行处理和解调判决以获得传输的数据。同时文中在这种方法的基础上引入了正交的第二支路进行并行处理和择优选取，可以进一步提高系统的稳定性和实用性。该算法克服了传统频偏纠正算法具有有限纠正范围的缺点，具有良好的通信性能，并且实现简单，捕获速度快，信息冗余度也较小。     

基于ARM处理器的Linux系统实时时钟的设计

文章使用DS3231芯片为基于ARM处理器的Linux嵌入式系统提供独立的实时时钟,处理器从DS3231获取精确的时间信息.介绍了ARM处理器与实时时钟芯片的接口电路设计.介绍了嵌入式ARM处理器和12C总线的通讯协议,介绍了Linux-2.6的驱动程序结构,并在此基础上给出了实时时钟驱动程序在实现方法.     

Analysis of Thermal Effects in Laser Rod Pumped by Repetitively Pulsed Laser Diode Array

Based on some assumptions, the numerical model of thermal distribution in solid state laser crystal pumped by pulsed laser diode is set up due to the pumped intensity distribution. Taking into account the property of YAG materials that varies with temperature, the transient temperature distribution of the laser crystal is calculated using finite element method on condition that K is a constant and a function of temperature. Then, the influence of the pumping parameters on the thermal effect in laser crystal is also discussed. This study is helpful to optimize the design of the diode side pumped solid state lasers.