3／4英寸录像机“CTL信号插入记录”功能的改装

在对录像磁带进行插入编辑如图像修改或声音编辑时，若错误地选择了组合方式，将会在编辑出点后出现一段无磁迹部分，用设备现有编辑功能是无法将这一段磁迹修复起来的，结果必须对其后的内容进行重新编辑或整版复制，由此造成各方面的损失。为了解决这一实际工作中不免要遇到的问题，在原有设备功能基础上可改装“CTL信号插入记录”功能，利用这一功能，基本完好地解决了3／4英寸录像编辑中遇到的上述问题。     

手机视频风向标——现状——看得见的 用得上的

现代通信的发展已有上百年的历史，在这一段并不算长的时间里面，人们相互之间的联系每天都在发生着变化，而通信设备的功用也在从传统的联系功能向着多元化的方向发展，手机视频作为当前最热门的话题之一引起了不少人的兴趣。一方面，手机视频将以前固定设备上的可视功能搬到了移动通信工具上，而功能的高度集成化一直是不少人所期望看到的；同时，这一功能对移动通信设备的处理能力、存储能力、显示能力以及网络的传送能力都提出了更高的要求。因此，无论是市场的需要，还是对技术高度的追求，客户与技术开发人员都有着基本一致的方向，这为手机视频的发展铺下了一条很有发展空间的光明大道。那么，手机视频技术到底发展到了一个什么程度，我们现在可以怎样利用这一功能呢?     

本地网联机计费网络管理系统

采用ＳＹＢＡＳＥ Ｃｌｉｅｎｔ／Ｓｅｒｖｅｒ结构体系的广域网系统平台，完成了市（县）本地网电话计费网络管理系统设计，并实现了一系统，介绍了这一系统的功能和特点，提出了计费数据联机集技术，这一技术可以大大缩短电话计费处理的周期。     

随时随地享受音乐——随身听／音频设备目前的状况

说到随身听，相信大家一定会觉得很亲切。1797年，也就是笔者出生的这一年，索尼推出了世界上第一台磁带随身听TPS-L2。这台机器只能完成磁带放间功能，不能录音、不能收间，也不带内置的杨声器，通过立体声耳机欣赏音乐，在推出这款产品之前，曾经有人质疑过这样一台功能单一的产品是否具有销路，     

宇达电通C516t，TMC上海首演

作为实时导航的一种重要延伸，TMC（Traffic Message Channel，实时交通信息）终于在上海掀起了神秘的盖头。虽然目前这一功能还显青涩，但在宇达电通看来，未来支持TMC功能的GPS设备将肯定拥有更多实时导航的话语权，甚至在某一时刻会成为行业霸主l。于是，C516t就在这样的背景下，作为目前惟一一款主打TMC功能的先行者上市了……     

液晶电视的这些功能你需要吗？

近年来随着液晶电视技术的发展，液晶电视的质量越来越高，这主要表现在清晰度和对比度不断提高、响应时间不断减小等方面。与此同时，液晶电视的各种功能也在不断增加。市场的激烈竞争，不仅表现在外观和性能上，新开发的各种功能也成为厂商争夺消费者的“亮点”。这些功能一般都不直接影响收看电视广播这一基本功能，大多是一些附加功能，比如流媒体功能、读卡功能、可录功能以及打印功能等。     

网元观点的PDH光传输系统信息模型研究

本文采用在ＩＴＵ－ＴＧ．８０５建议中定义的传送网通用功能结构模型，建立了ＰＤＨ传送网功能结构模型；在这一达网功能结构模型的基础上，结合ＰＤＨ光传输系统的网管要求，建立了网元观点的ＰＤＨ光传输系统信息模型。     

录像机定时记录功能与卫星电视接收机电源开关的同步控制

录像机定时记录功能与卫星电视接收机电源开关的同步控制黑龙江省拜泉县电化教育馆张东兴各种录像机中，都设置了ＴＩＭＥＲ（定时器）记录功能和ＯＴＲ（即时）定时录像功能。利用这一功能，可节省人力，减少候机操作时间，特别在录制节目工作量较大的教育卫星电视地面接...     

来自3G的诱惑——3G时代的最佳上网设备选购

数年前，能够随时随地上网对我们来说还是一个奢侈的事情，黑莓手机仅凭移动电子邮件功能，就获得了众多商业用户的青睐。而这一简单的功能对于经常旅行的笔记本电脑用户而言却是难以实现的。     

我的家庭“梦”院

一直以来，笔记本在大多数人看来只是一个工具面已，翻一覆去怎么看也都只是一部由众多电阻零件拼凑而成的机器。不过那已经是老观点了。在现在看来，笔记本电脑已经成为家庭生活中不可缺少的组成部分，而它的功能也不仅仅是计算这么简单。早期，笔记本厂商试图把CD播放机的一些功能整合在笔记本中，这便有了关机播放功能的诞生。     

通信网络安全防护综述

随着通信网络IP化不断发展以及通信业务的多样化发展,通信网络面临越来越多的安全威胁.如何应对安全威胁进行有效的安全防护是当今通信网络面临的重大挑战,本文综合分析了当前通信网络面临的安全形势,提出了通信网络的安全防护措施,对重要系统以及新业务网络的安全防护方法.     

Historical review of OCR research and development

Research and development of OCR systems are considered from a historical point of view. The historical development of commercial systems is included. Both template matching and structure analysis approaches to R&D are considered. It is noted that the two approaches are coming closer and tending to merge. Commercial products are divided into three generations, for each of which some representative OCR systems are chosen and described in some detail. Some comments are made on recent techniques applied to OCR, such as expert systems and neural networks, and some open problems are indicated. The authors' views and hopes regarding future trends are presented     

Environmental stress screening strategies for complex systems: A 3-level mixed distribution model

Environmental Stress Screening (ESS) is employed to reduce, if not eliminate, the occurrence of early field failures. In this paper, a three level ESS model is presented for a complex electronic system. Screening is performed at the component, board and system level. Components are screened for a specified duration before being assembled into printed circuit boards (PCBs). Defects introduced during the assembly of the PCBs are screened at the board level, while defects introduced during final assembly are screened at the system level. Components and connections are assumed to come from good and substandard populations and their times-to-failure distributions are modeled by mixed distributions. Mixed exponential distributions are used to model component timesto-failure and mixed Weibull distributions are used to model the times-to failure for board and system level connections. The mixed Weibull distributions are used to model wear-out characteristics at the board and system level. Optimal screen durations in the presence of wear-out are obtained by minimizing the systems life-cycle cost. ESS is shown to be a cost effective strategy when properly implemented. The optimal screening strategies are shown to be relatively robust to the system warranty period.     

Analysis of conjugate gradient algorithms for adaptive filtering

The paper presents and analyzes two approaches to the implementation of the conjugate gradient (CG) algorithm for filtering where several modifications to the original CG method are proposed. The convergence rates and misadjustments for the two approaches are compared. An analysis in the z-domain is used in order to find the asymptotic performance, and stability bounds are established. The behavior of the algorithms in finite word-length computation are described, and dynamic range considerations are discussed. It is shown that in finite word-length computation and close to steady state, the algorithms' behaviors are similar to the steepest descent algorithm, where the stalling phenomenon is observed. Using 16-bit fixed-point number representation, our simulations show that the algorithms are numerically stable     

通信侦察技术未来发展方向探讨

首先回顾了当前通信侦察所面临的技术挑战,分析了现有技术基础的不足之处,根据新的军事需求提出了若干需要研究的方向,探讨了可能的有效技术途径,给出了一些初步的研究结果示例,最后描述了这些新技术的应用方向。     

Electrical characterization of the SiO2---Si system

The classical capacitance-voltage measurement methods and the conductance technique which are frequently used to analyze the SiO₂---Si system, are briefly introduced and critically evaluated. These measurement techniques are based on macroscopic device structures, average structure parameters are determined. Transient and random telegraph signal measurements, and charge pumping are now available as new methods to study the SiO₂---Si interface in sub-μm device structures. These techniques permit to analyze single, individual traps in the interface. Traps in small devices are isolated. The capture rates are thermally activated by the Coulomb energy.     

无源定位观测方程的两类伪线性化方法及渐近最优闭式解

为避免无源定位中的迭代运算,该文针对两类特殊的无源定位(非线性)观测方程,分别提出将其进行伪线性化处理,从而实现目标位置闭式解算的理论分析框架.首先,在不限定具体物理观测量的前提下,归纳总结出两类将非线性观测方程转化为伪线性观测方程的数学模型,并推导出用于目标定位的加权线性最小二乘闭式解.接着,利用一阶误差分析方法定量分析两类闭式解的理论定位方差,并证明其参数估计性能均能够达到相应的克拉美罗界(在门限效应发生前),从而证明闭式解的渐近最优性.最后,文中以AOA/TOA联合定位和AOA/TDOA/FDOA联合定位为算例,分别阐述两类伪线性化无源定位方法的具体应用,并通过仿真实验验证文中理论分析的有效性.     

Coupling Between Guided Surface Waves, Lateral Waves, and the Radiation Fields by Rough Surfaces--Full-Wave Solutions

In this paper explicit expressions are presented for the guided surface waves and lateral waves that are excited when radiation fields are incident upon rough surfaces. Similarly, expressions are presented for the radiation fields scattered by rough surfaces that are excited by surface waves and lateral waves. In addition, coupling between the surface waves and the lateral waves due to surface irregularities is considered in detail. The solutions, which are based on a full-wave approach to the problem, are subject to the exact boundary conditions at the irregular interface. These are shown to be consistent with the reciprocity relationship in electromagnetic theory. The validity of the approximate impedance boundary condition is examined and consideration is given to excitation at the grazing incidence, the Brewster angle, and to waves incident at the critical angle for total internal reflection. Optimum conditions are determined for coupling between the radiation fields, the surface waves, and the Iateral waves incident upon irregular boundaries. Thus this work is applicable to problems of radio wave propagation near an irregular interface between two media and excitation of guided waves by irregular dielectric structures.     

混合型级联多电平变换器调制策略研究

多电平变换器的调制策略与其主电路拓扑密切相关。文章首先讨论了几种多电平变换器的拓扑特点,推荐了一种混合型多电平变换器,分析了它的几种调制策略和频谱特性,并进行了电路仿真,比较了它们之间的优劣,给出了连续调制方式下的频谱表达式,仿真验证了结果的正确性,最后总结了几点有用的结论。     

Effect of PLL frequency synthesizer in FSK frequency-hoppedcommunications

Synthesizer transient and spur effects in an frequency-shift-keying frequency-hopped system are investigated. Models for transient analysis are developed, and resulting degradations to performance are computed. Compensation methods, such as ping-ponging multiple synthesizers and gating symbol detectors, are considered. A spur analysis is presented, and the overall output effects on hopping spectrum and demodulation are shown. Methods to bound degradation in terms of number and strength of spur lines are presented