2GHzDS—CDMA个人通信与数字微波通信系统电磁兼容优化设计

针对２ＧＨｚ－ＤＣ－ＣＤＭＡ个人通信系统与数字微波通信系统的电磁兼容问题提出了优化设计方案，一是优化ＤＳ－ＣＤＭＡ基站布局；二是优选高性能天线；本文给出的优化设计方案对于加快发展我国的ＤＳ－ＣＤＭＡ个人通信系统具有较强的理论指导意义，实施后会产生较大的经济效益。     

CMA,PCS（3GM）与NⅡ／GⅡ

本文式图对当前移动通信发展中的几个热点问题联系起来探讨其发展趋势。首先是ＣＤＭＡ的优势２与总是何在。文中指出，ＣＤＭＡ的优势在容量，而问题在于它是功率和干扰受限系统。其次是Ｎ－ＣＤＭＡ在第二代和二代半移动通信中的应用前景，预计１９９７年将见分晓。Ｗ－ＣＤＭＡ将在第三代移动通信，即个人通信，例如ＩＭＴ－２０００和ＵＭＴＳ中成为优选方案之一。在未来的信息调整公路中Ｂ－ＣＤＭＡ将是解决无线接入的关键技术     

W-CDMA无线多媒体通信系统设计考虑

为了研究和开发第三代移动通信系统,进行Ｗ－ＣＤＭＡ 无线多媒体通信系统和技术的研究十分必要。针对我们个人通信与扩频实验室正在研究开发国家８６３ 高技术通信主题Ｗ－ＣＤＭＡ无线多媒体通信技术的实验系统,我们提出了Ｗ－ＣＤＭＡ无线多媒体通信系统的系统结构,系统信道配置和功能安排,Ｗ－ＣＤＭＡ通信方式,分析了信号调制解调的性能,提出信号功率控制方法。     

第三代移动通信系统的佼佼者—宽带CDMA

本文通过分析移动通信与个人通信的发展趋势,认为基于ＩＳ－９５标准的Ｗ－ＣＤＭＡ系统是第三供移动通信系统中前景看好的代表系统。文章阐述了Ｗ－ＣＤＭＡ的优势,有待解决的问题以及支持Ｗ－ＣＤＭＡ的新技术,本文工作得到了“８６３”高科技计划个人通信项目组的支持。     

M30MSC/VLR

Ｍ３０ＭＳＣ／ＶＬＲ随着全球移动通信的发展以及ＣＤＭＡ移动通信技术的成熟和投入商用，ＣＤＭＡ逐渐成为移动通信和个人通信（ＰＣＳ）的实现方式．ＣＤＭＡ以其容量大，话音质量高、保密性好、成本低等优点，在数字蜂窝系统中将逐渐占据主导地位．ＭＢ３０系统是８０...     

基于CDMA的第三代移动无线通信系统（上）

基于ＣＤＭＡ的第三代移动无线通信系统（上）ＡｌｆｒｅｄＢａｉｅｒ等在未来的蜂窝区移动和个人通信中，码分多址联接（ＣＤＭＡ）是一门很有前途的技术。ＣＤＭＡ为蜂窝区通信提供了一些有吸引力的特性，例如在频谱效率高、容量适度、软切换和宏分集、低频复用组规模、...     

从cdmaOne到Cdma2000的无缝演进路径

在２０００年世界无线电大会上，第３代移动通信系统（３Ｇ）的地面系统被确定可使用５种无线传输技术，它们是ＣＤＭＡ－ＤＳ、ＣＤＭＡ－ＭＣ、ＣＤＭＡ－ＴＤＤ、ＴＤＭＡ－ＳＣ和ＴＤＭＡ－ＴＤＤ。其中前３种基于ＣＤＭＡ（码分多址）技术，后两种基于ＴＤＭＡ（时分多址）技术。可见，在３Ｇ标准中，ＣＤＭＡ是主流技术。ＣＤＭＡ（Ｃｏｄｅ Ｄｉｖｉｓｉｏｎ Ｍｕｌｔｉｐｌｅ Ａｃｃｅｓｓ）蜂窝系统由于采用了一种称之为扩频的通信技术，所以与采用ＴＤＭＡ和ＦＤＭＡ（频分多址）的ＧＳＭ蜂窝系统相比，具有抗干扰性好、系统容量…     

国外点滴

国外点滴采用ＣＤＭＡ和ＧＳＭ技术的个人通信业务试验Ｓａｎｄｌｅｇｏ，ＣＡ—Ｑｕａｌｃｏｍｍ以及加拿大ＢｅｌｌＭ。ｂｉｌｉｔｙ公司拟共同试验用码分多址（ＣＤＭＡ）以及ＧＳＭ数字蜂窝技术的个人通信业务。试验将在多伦多进行，在１．９ＧＨｚ频段上采用由Ｑｕａ...     

美国带内同频道数字音频广播（DAB）的开发状况

欧洲尤里卡１４７／ＤＡＢ方式在世界范围内推出后，很多国家正在对这种方式进行实验和开发。但是，美国广播界却另辟蹊径，他们正在开发一种不同于尤里卡１４７／ＤＡＢ的带内ＤＡＢ方式，该方式有两种：带内同频道ＤＡＢ方式（ＩＢＯＣ ＡＭ－ＤＡＢ，ＩＢＯＣ ＦＭ－ＤＡＢ）和带内邻频道ＤＡＢ方式（ＩＢＡＣ ＡＭ－ＤＡＢ，ＩＢＡＣ ＦＭ－ＤＡＢ）。本文详细介绍美国ＵＳＡ Ｄｉｇｉｔａｌ Ｒａｄｉｏ公司开发的带内同频     

同步CDMA系统中一类新的扩频序列

码分多址（ＣＤＭＡ）技术已作为第三代数字移动通信及个人通信系统的无线接入技术进行广泛的研究和应用。而ＣＤＭＡ系统中扩频序列问题一直是ＣＤＭＡ技术中的关键问题。文献４给出了Ｓ－ＣＤＭＡ系统中的扩频序列实数加编码的新方法,但对构造具有纠错能力的扩序列至今尚未发现。本文给了了Ｓ－ＣＤＭＡ系统中具有纠错能力的一类新的扩频序列和它的译码算法。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.