任意进制计数器设计方法初探

以一组典型的TTL芯片为例,介绍了对于不同的集成计数器芯片,怎样通过反馈复位法,来构成任意进制计数器;最后给出了详细的设计步骤。     

用74LS290构成任意进制计数器的方法

计数器是数字系统中的应用最广泛的时序部件,74LS290是一个典型的集成异步计数器.本文从74LS290的结构和功能出发,介绍采用74LS290构成任意进制计数器的方法.     

任意进制计数器的仿真设计与制作

以典型的74LSl60同步十进制计数器为例,运用反馈清零法和反馈置数法设计六十进制计数器来讲述任意进制计数器的设计方法;用Proteus软件进行仿真设计,该设计方法灵活直观,可以在缺少硬件的条件下能很快对所设计电路的正确性进行验证;通过万能板完成电路制作,进一步验证理论设计的正确性。通过该方法的学习,可加深学生对计数器的理解,提高学生的电路设计和动手能力。     

采用MSI芯片数字设计方案的比较与选择

中规模集成电路(MSI)，具有较强的通用性，能够适用于不同的系统中。由于器件的功能较强，而电路结构比较简单，这就为用较少的芯片实现所要求的功能、降低成本提供了可能。本针对采用MSI芯片进行数字设计出现多种方案情况，从几个方面对问题进行了讨论，同时结合实例对逻辑设计中出现的方案进行了对比和评价。     

集成计数器构成任意进制计数器的方法

在介绍了几种典型集成计数器状态表的基础上，结合例题介绍了使用集成计数器构成任意进制计数器的方法。     

集成计数器构成任意进制计数器的方法

在介绍了几种典型集成计数器状态表的基础上,结合例题介绍了使用集成计数器构成任意进制计数器的方法.     

集成计数器构成任意进制计数器的方法

在介绍了几种典型集成计数器状态表的基础上,结合例题介绍了使用集成计数器构成任意进制计数器的方法。     

用集成计数器构成任意进制计数器

通过对计数原理的分析,系统地讨论了用已有的集成计数器产品构成任意N进制计数器的方法。     

MSI中规模计数器设计课程中的教法探讨

在数字电子技术课程的教学中有一章专门讨论时序逻辑电路的分析与设计,随着MSI中规模芯片的普及,大量的MSI计数器芯片进入了教材。由于课时的限制,教师不可能全面讲授这类芯片的设计方法,从而导致许多同学在考研时或在毕业后的工作中遇到不同的MSI芯片设计时就会出现困难。为此在本文中,我利用多年的教学经验总结归纳了此类问题的相关特征和简便的设计方法,为在校电子专业学习的同学们和从事电子专业教学的教师们提供一个参考。     

用集成计数器构成M进制计数器

着重介绍了用集成计数器构成M进制计数器的常用方法.     

双栅极空气计数管的工作电压研究

Based on analysis of the discharging course in double grid air counter(DGAC),the dischargin model is built up by applying the conception of average ionizaing free path.An effective algorithm is presented for the working voltage of DGAC using this model.The working voltage is nearly related to the geometric parameters of DGAC,the sensitivity of the circuitry and the number of discharges,computing results confirm that the working voltage increases with the ratio of the radius of the anode to that of the cathode.The number of discharges follows the similar rule.     

永磁直线同步电机磁阻力优化的设计

The detent force of a permanent magnet linear synchronous motor （PMLSM） is analyzed and the corresponding optimization methods are presented to reduce it. The detent force, which is divided into two components, i.e. resulting from the end effect and resulting from the slotting effect, can be analyzed respectively by the finite element method （FEM）. To reduce the detent force arising from the end effect, several optimal design techniques are utilized, namely, adopting the suitable length and end shape of the primary armature. The detent force resulting from the slotting effect is reduced by means of skewing and adjusting the width of the magnets mounted on the secondary armature, and adopting the fractional slots of the primary armature. The validity of the analytical detent force predictions and the effectiveness of the detent force reduction techniques are verified by the experimental measurements.     

基于VB6.O的数码计时器的设计与实现

Visual Basic 6.0是一种面向对象的可视化程序设计语言，提供了集界面设计、编写代码和程序调试等于一体的集成开发环境．本文通过数码计时器的设计与实现说明在VB环境下开发应用程序的思路和步骤．     

Design and application of learning environments based on integrative problems

This work reports on the results obtained from the application of learning environments on the basis of one integrative problem and a series of other smaller problems that limit the contents to be investigated and learned by the students. This methodology, which is a variation to traditional problem-based learning approaches, is here illustrated in terms of its application in an engineering economics course, a subject that is taught in most engineering programs. The purpose of this methodology is to improve students’ learning, which is measured through the students’ academic performance and their learning strategies, and to characterise them as a function of these variables. The results obtained after the systematic application of this methodology are positive. The surveyed students showed significant changes in the examined variables as well as in their satisfaction and motivation level, and in their commitment to learning.     

基于VRML技术的虚拟实验室的设计与实现

虚拟实验有助于提高学生的自主学习兴趣、创新能力、实际动手能力和综合素质。针对实验教学的特点,对基于VRML技术的虚拟实验系统进行功能分析和结构设计,并对虚拟模型的建立和优化、虚拟实验中的交互以及交互过程中对数据库的访问等关键技术进行研究。实践证明,基于VRML的虚拟实验系统是切实有效的。     

一个基于VB与MATLAB实验系统的设计与实现

本文介绍了运用VB与MATLAB混合编程方法研制的《高等数学应用问题与数字信号处理虚拟实验系统》的设计和实现方法及其相关的关键技术。本系统融合了VB和MATALB的优点,做到VB与MATLAB的无缝连接,无论是掌握或没有掌握VB和MATLAB的师生都能无障碍地用于课堂教学。本系统是一个开放性的系统,可以随时对问题库进行扩容,也可以添加相应课程模块。     

Effects of rarefaction on the characteristics of micro gas journal bearings

Given the definition of the reference Knudsen number for micro gas journal bearings, the range in the number is related to the viscosity of air at different temperatures. A modified Reynolds equation for micro gas journal bearings based on Burgdorfer＇s first-order slip boundary condition is proposed that takes into account the gas rarefaction effect. The finite difference method （FDM） is adopted to solve the modified Reynolds equation to obtain the pressure profiles, load capacities and attitude angles for micro gas journal bearings at different reference K_nudsen numbers, bearing numbers and journal eccentricity ratios. Numerical analysis shows that pressure profiles and non-dimensional load capacities decrease markedly as gas rarefaction increases. Attitude angles change conversely, and when the eccentricity ratio is less than 0.6, the attitude angles rise slightly and the influence of the reference Knudsen number is not marked. In addition, the effect of gas rarefaction on the non-dimensional load capacity and attitude angle decreases with smaller bearing numbers.     

浅谈多媒体课件的制作

本文针对当前多媒体课件制作中存在的问题,全面、细致地介绍了多媒体课件的含义、特点和制作的一般过程,及现代教育思想理论和系统科学方法的指导作用,强调课件制作的系统设计方法,旨在对问题的解决起到抛砖引玉的作用.     

基于一种新的缺陷地结构的低通滤波器的设计

A novel defected ground structure （DGS） for the microstrip line is proposed in this paper. The DGS lattice has more defect parameters so that it can provide better performance than the conventional dumbbell-shaped DGS. Selectivity is improved by 97.2% with a sharpness factor of 24.6%. The method is applied to the design of a low-pass filter to confirm validity of the proposed DGS.     

最大功率点跟踪的太阳能光伏发电系统实验平台设计

设计了太阳能光伏发电铅蓄电池充电的简易实验教学平台,由光伏电池板、充电控制器、阀控式铅蓄电池和变阻箱负载构成。以近似梯度值计算代替一阶求导,提出了一种变步长的电压扰动观察法来实现太阳能光伏发电最大功率点跟踪(MPPT)。以STM8S105单片机为控制器核心,采用Buck直流降压斩波主电路,结合铅蓄电池四阶段充电方式,进行系统硬件和软件设计。测试表明,该实验平台具有MPPT功能,造价较低、结构简单、性能良好、易于操作和维护,能够满足实验教学的要求。