高性能微电流集成放大器的设计

介绍了用ICL7650运算放大器设计高性能微电流集成放大器的方法,阐述了电路的工作原理和提高放大器性能的措施,给出了实际应用的实验结果。该放大器测量范围10^-9～10^-12A,自换量程,自动校零,测量准确,工作稳定。     

基于噪声分析方法的微电流快响应放大器

介绍了基于噪声分析方法，测量ADS次临界反应堆动态参数的微电流快响应放大器设计原理、线路及测试结果。     

直流微电流前置放大器的研究

介绍了一种直流微电流放大器的设计,先通过原理分析,指出应重点注意的一些关键性问题及提高信噪比的途径.并以此设计了实用电路,给出测试方法及测试数据.该放大器具有分辨率高、响应快、漂移低、稳定性好以及价格低廉等优点,非常适合光电流、生物电流及射线电流测量.     

分布电容对微电流放大器响应性能影响分析及实验研究

本文分析比较了基本放大电路、T型反馈放大电路、高频补偿T型反馈放大电路和并联补偿放大电路四种微电流放大电路的响应特性。研究了转移电阻和布线引入的分布电容对放大电路增益和响应速度的影响。探讨了影响微电流放大器的稳定性、可靠性因素以及提升放大器的稳定性和可靠性的措施。对并联补偿放大电路脉冲响应的时间常数进行了测试,测试结果为80μs。理论分析和实验研究表明,并联补偿放大电路具有增益大、响应速度快等优点,稳定性好,可靠性高,在离子迁移谱中具有良好的应用前景。     

用于ADS启明星1#中子涨落特性测量的微电流放大器研制

通过对次临界反应堆中子噪声特性的分析,设计了一种能反映ADS系统启明星1#实验装置中子涨落特性的微电流放大器。通过设计和调试,该放大器能够实现10^-9－10^-11A的电流－电压通频带转换放大,达到了设计的要求。     

用于ADS次临界反应堆Keff测量微电流放大器的设计

设计了一种基于噪声分析方法,利用反应堆堆芯中子涨落特性测量加速器驱动洁净核能系统（Accelerator driven system,ADS）次临界反应堆动态参数的微电流放大器,并且根据需要设计了微电流源,运用Protel实时电路仿真工具对放大器进行仿真调试,使其达到设计要求。     

用于自给能探测器的反函数放大器

目前,世界上核电站广泛采用自给能探测器做为堆芯通量的描绘和控制.自给能探测器优点是:结构简单;牢固;尺寸小;燃耗低;不需外加偏压。它的缺点是响应时间较慢。采用反函数放大器就可以解决这个问题。本文介绍了使整个系统的总时间常数比系统组成部分的时间常数短得多的方法,并介绍了反函数放大器的线路。     

基于FPGA的数字电源调节器研究与设计

详细描述了基于FPGA方案的数字电源调节器。首先介绍了数字调节器的硬件功能模块设计,重点对用于采样电源输出电流的高速高精度AD7634的工作原理做了描述,并给出了AD7634采集一个电压信号的工作波形;其次介绍了数字调节器的软件设计,包括调节器算法、功能以及在FPGA内的实现方法;最后,以一台15 A/15 V校正磁铁电源为样机,进行了闭环调节实验,给出了测试结果。     

Design and Test of a Nuclear Radiation-Tolerant Servo Amplifier

A servo amplifier was designed to meet the nuclear radiation environment expected in the nuclear ramjet missile. An extensive search of radiation effects data was made to Judiciously select radiation resistant components and materials. The resulting design used RCA nuvistor tubes for voltage amplification, and power amplification was achieved with G. E. ceramic tubes. The amplifier was instrumented to evaluate individual stage performance. Irradiation testing was conducted over a 130 hour period and the unit was subjected to an integrated fast neutron flux of 2.0 × 1017 neutrons/cm2 (E>0.3 Mev) and an associated gamma dose of 2.5 × 1011 ergs/gm-(C). The servo amplifier operated throughout the test with negligible changes in amplifier characteristics.     

一种中子探测器放大电路的设计与实现

介绍了一种可用于中子探测器的放大电路的设计与实验验证。该电路由前置放大器、主放大器、脉冲幅度甄别器和触发器四部分组成。该电路采集正比计数管产生的微弱信号,由两级放大器对初始信号进行放大,并由脉冲幅度甄别器进行甄别成形,触发器形成固定宽度的方波脉冲供后续单片机系统采集计数。整机探测器在天然本底、252Cf中子源及模拟信号发生器下分别进行实验测试,实验结果证明了该放大电路的可靠性以及在中子探测器中的可用性。     

The Need for Flexibility in Amplifier Design

Improvements in detector resolution and increases in the sophistication of nuclear experiments have placed an entirely new emphasis on linear amplifier design. Just a few years ago it was necessary to have specialized amplifiers to deal with each specific problem. The lack of flexibility now plaguing most existing linear pulse amplifying systems is often quite annoying to the user. Invariably, the user will find the amplifying system failing in part to provide either adequate stability, polarity reversibility, clipping mode selection, control of rise and fall times, adequate control of gain, or threshold cut and expansion. What usually ensues is that large amounts of time and effort are expended in modifying existing amplifiers in order to accomplish the particular job at hand, or the Job is done with an existing system where poor amplifier performance is accepted as a necessary evil. In the past several years many notable pulse amplifiers have been produced. Among these are the DD-2, the A-8, and the alpha amplifiers designed under the direction of Fairstein, Borkowski, and Blankenship at the Oak Ridge National Laboratory. Although these amplifiers show exceptional performance in their particular specialized application, all of these amplifiers lack the flexibility desired in a modern general-purpose laboratory amplifier. What is needed today is an amplifying system possessing the best basic features of these highly successful amplifiers with the addition of the features mentioned earlier to obtain greater flexibility and therefore greater utility. In early 1961, an amplifying system of this type was introduced at LRL.     

自动频率跟踪数字锁相放大器设计

在光电检测系统的设计中,往往采用锁相检测系统来消除1/f噪声和其他外部的噪音。论文是在Alter公司DSP Builder基础上设计的数字锁相放大器,同时为避免待测信号与参考信号的失配,增设了频率自动跟踪模块,从而更好地实现参考信号频率的匹配,确保测量精度。经过仿真验证可行后,将编译好的程序下载到FPGA器件中,并对硬件电路进行设计和测试。实验结果表明,在待测信号的信噪比RSNR≈-10 d B时,最小检测幅值为50μV,锁频相对误差小于0.015%,待测信号幅值的测量相对误差小于0.11%。因此该自动频率跟踪数字锁相放大器可以有效实现微弱光电信号的检测。     

脉冲核磁共振硬脉冲序列发生器的设计

以C8051F020单片机为核心控制单元,控制DDS芯片AD9850和CPLD芯片EPM7512AETC144-10,设计了应用于脉冲核磁共振装置中的硬脉冲序列生成器,能产生IR和CPMG等硬脉冲序列,适用于0.6T及以下的主场装置.实验表明,该设计具有稳定性好,自动化程度优良和性价比良好的特点,具有很高的实用价值.     

微弱光电流信号放大器的设计

针对等离子体物理实验装置托卡马克(EAST)实验中微弱信号的探测需要,结合EAST的恶劣电磁环境以及光电检测电路的基本工作原理,设计了一种实用的光电弱信号电流放大器.电路由前置电流放大器、有源滤波放大电路构成,结合电磁兼容技术对信号进行接地和屏蔽,以及合理布线,旨在保证增益和带宽的同时降低噪声.实验表明,基于本设计的光...     

基于AD7888的嵌入式便携测量仪的设计与实现

传统的测试仪器只能对数据进行采集存储,并不能对获得的数据进行显示,文章介绍了一种以arm为控制核心的具有液晶显示屏的便携式测试系统,该系统能将采集到的数据实时地在界面上显示出来,系统采用S3C2440处理器和AD7888做为硬件平台,并在Linux操作系统上开发出了相应的应用程序,能够实现数据的采集存储、处理、波形显示等功能。为了功能上的完备性,外扩了USB接口。     

ITER Magnet Feeder:Design,Manufacturing and Integration

The International Thermonuclear Experimental Reactor(ITER) feeder procurement is now well underway.The feeder design has been improved by the feeder teams at the ITER Organization(IO) and the Institute of Plasma Physics,Chinese Academy of Sciences(ASIPP)in the last 2 years along with analyses and qualification activities.The feeder design is being progressively finalized.In addition,the preparation of qualification and manufacturing are well scheduled at ASIPP.This paper mainly presents the design,the overview of manufacturing and the status of integration on the ITER magnet feeders.