共查询到20条相似文献，搜索用时 718 毫秒
1.
《实验室研究与探索》2017,(11):36-39
中心频率自动可调的跟踪滤波电路是一种应用广泛的带通滤波电路。提出了一种基于开关与电阻串联调制方法的跟踪滤波器电路实现方法。开关电阻支路通过适当的电路连接方式并以一定的方式控制开关的通断,可产生所需要的等效电阻。从能量等效的角度给出了开关电阻支路等效电阻的计算方法。讨论了基于开关电阻调制的跟踪滤波器设计方法。设计了双二次结构的带通跟踪滤波器,该电路由1片四运放芯片AD713、2片模拟开关芯片DG418以及若干电阻、电容元件组成。采用Proteus对跟踪滤波器的特性进行测试,其结果与理论分析吻合,为跟踪滤波器的实际应用提供了可靠的依据。 相似文献
2.
采用新型CMOS电流反馈运算放大器以及电阻和电容元件模拟无源LC梯型高通滤波器电路，得到了一种高频特性优良的容易全集成的连续时间有源全极点高通滤波器。以三阶高通滤波器的实际电路为例用OrCAD软件进行了MOS管级的计算机仿真，结果表明本文所出的电路方案是正确可行的。这种技术在高频高速模拟集成电路的设计中有较大的实用价值。 相似文献
3.
4.
本文主要介绍电容式加速度计采用差动电容检测电路的数学原理,着重阐述微加速度计的电容变化率为微弱输入信号的检测技术实现.并在设计分析检测微小电容变化量的电路基础上,进一步采用开关型电路,来实现检测的电容变化率目的. 相似文献
5.
介绍了基于恒流源电路的自动电阻测试仪。通过由运放电路构成的线性宽量程电阻电路完成对不同电阻的测量,并由模拟开关完成对电阻量程的自动切换。设计采用自带A/D模块的AVR单片机ATmega16作为主控芯片,完成对模拟电阻值的采集与转换、电机辅助装置的控制以及相应的数显功能。 相似文献
6.
提出一种适合输入串联型正激、反激变换器的无源缓冲环节.该无源缓冲环节由吸收电容、耦合电感以及二极管构成.在各串联电路中,利用吸收电容吸收变压器在开关管关断后的剩余能量,通过耦合电感与吸收电容的谐振工作将该能量向变换器的输入侧回馈.采用耦合电感使各串联电路在开关管关断期间具备自然均压能力,同时各吸收电容具备自然均压能力,可确保各串联电路开关管的电压均衡.以该类反激变换器为研究对象,对所提无源缓冲环节的工作过程、设计要素等进行分析,设计1.5 kV的该类变换器实验样机进行实验研究,实验结果证明了所提方法的可行性. 相似文献
7.
田宗戚 《数理化学习(高中版)》2005,(9)
在电磁学中,有许多涉及电量的物理问题. 从引起的原因上可以做如下的归类: 一、由电容器电量的变化引起问题1 在图1中所示的电路中,电源的电动势为E,内阻为r,电容器的电容为C,电阻的阻值为R,求开关S断开后,流过电阻R的电量. 相似文献
8.
为了描述和解释开关电容电路的电磁辐射现象，引入了一个等效辐射阻的概念，当开关电容电路工作在高频时，它的仿真电路模型应该考虑这个等效的辐射电阻。 相似文献
9.
从时变参量元件及电路的定义出发,分析研究了属于电阻性电路形式的时变跨导电路,模拟乘法器电路,开关函数的三种线性时变参量分析法. 相似文献
10.
高考"恒定电流"的重点是闭合电路欧姆定律的应用,电功、电热的计算, 电阻、电压和电流的测量.其中电路分析--包括电阻变化、含电容电路、非纯电阻电路等动态分析, 运用电路知识探究联系实际问题已成为考查的热点, 近几年设计性电学实验是每年必考内容. 相似文献
11.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
12.
13.
14.
《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
15.
Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
16.
《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
17.
YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献
18.
Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
19.
20.
GUO Bao-feng Xiao Da-wei 《重庆大学学报(英文版)》2005,4(3):129-133
Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching. 相似文献