贴片机脱机编程的快捷方法

SMT生产线中的大多数加工设备均为数控设备。它们编程所需要的大多数特征数据均可从CAD设计系统中得到。文章介绍了如何从CAD设计系统中导出X、Y坐标数据,并转换成贴片数据的方法和思路,以期引起更多的同行加入到这方面的研究中。     

AlGaAs／GaAs HBT集成电路的CAD

介绍了一套用于ＡｌＧａＡｓ／ＧａＡｓＨＢＴ集成电路的ＣＡＤ软件，它可完成ＨＢＴ的器件模拟、模型参数提取及电路模拟。应用该软件对ＨＢＴ运算放大器进行了模拟，为电路的研制提供了依据。     

Analysis of end point vibrations of a two-link manipulator by integrated CAD/CAE procedures

In this work, the effect of flexibility on the trajectory of a planar two-link manipulator is studied using integrated computer-aided design/analysis (CAD/CAE) procedures. The solid models and finite element models of the parts of the manipulator are created by using the CAD/CAE software I-DEAS. The assembly is defined, and knowing the payload and the end point trajectory, the velocities and accelerations of the parts, joint forces and driving torques are calculated using the rigid body dynamics. All the time dependent nodal forces acting on the parts including distributed gravity and inertia forces are created in files with the I-DEAS program file format. The finite element vibration analysis of the parts is performed by I-DEAS. The end point vibrations and the deviations from the rigid-body trajectory are analyzed for different types of end point acceleration curves. A circular trajectory is considered as an example. It is observed that the precision of the manipulator can be increased by testing different end point acceleration curves without changing the trajectory and the duration of the end point work. The procedure explained in this work can be used for this purpose successfully.     

新型微波有源滤波器综合方法

本文给出了一种新颖的微波有源滤波器的拓扑结构及综合方法，并对有源滤波电路进行了计算机模拟，结果表明本文给出的微波有源滤波器电路具有优良的的窄带滤波特性，通带内正向增益大于１０ｄＢ，带外抑制大于３０ｄＢ。     

深亚微米条件下的多层VLSI／MCM层分配的遗传算法

本文提出了一个深亚微米条件下的多层ＶＬＳＭＣＭ有约束分层层分配的遗传算法。该算法分为两步：首先进行超层分配，使各线网满足Ｃｒｏｓｓｔａｌｋ约束，且超层数目最少；然后进行各超层的通孔最少化二分层。与目前的层分配算法相比，该遗传算法具有目标全面，全局优化能力强等特点，是一种可应用于深亚微米条件下的ＩＣ ＣＡＤ的有效分层方法。     

用边界元法提取VLSI版图电阻

介绍了ＶＬＳＩ版图验证中电阻提取的基本原理和主要方法，给出了一种新颖的基于边界元法的电阻提取算法。该算法采用变节点单元，较好地解决了实际问题中经常出现的角点问题。通过应用该算法对几个实例进行提取，证明使用本文的算法不仅在精度上而且在占用ＣＰＵ时间上都取得了令人满意的效果     

VHDL逻辑综合及FPGA实现

运用ＶＨＤＬ语言描述了一个１２×１２位的高速补码阵列乘法器。重点是运用ＶＨＤＬ逻辑综合优化该乘法器，并进行了乘法器的ＸｉｌｉｎｘＦＰＧＡ实现、功能仿真和时序仿真。经选用ＸＣ４００５ＰＣ－８４－４芯片进行验证，证明了其正确性     

CAD OF MILLIMETER WAVE OSCILLATORS WITH THE FDHB TECHNIQUE

In this paper the modelling, analysis and optimization of millimeter wave oscillatorsare investigated by using the a frequency-domain harmonic balance technique (FDHB), where theexternal-circuit impedances looking outside from the active device are calculated with a combinedtechnique of modes expansion, Galerkin, and collocation methods. The optimization results arein agreement with the experimental ones, which show the reliability of the presented model andoptimization.     

三维射频加速腔程序包MAFIA的开发和应用

介绍了三维射频加速器计算机辅助设计(CAD)程序包MAFIA的特点、功能及其应用。用CAD的方法实现了射频加速器特别是非轴对称带耦合腔的加速器的三维腔形设计。同时介绍了节省内存、节约机时的模型方法,使得在中小型机器上运行大程序(八万条)成为可能。文章主要对L波段的加速腔进行了数值模拟,并和实验进行了比较,结果符合较好;通过三维数值模拟及图形模拟的方法比较了各种形状谐振腔的性能;计算分析了输入耦合腔及高阶模耦合器对加速腔电磁场分布等参量的影响;提出了加耦合器后谐振频率改变的补偿方法。     

XML在机械CAD系统中的应用

分析了Internet上最新的XML技术的特点，通过实例用XML技术对机械CAD产生的各种文档信息进行了描述，并且构造了基于XML文档交换的分布式支持环境的体系结构。