程控增益放大器设计

程控增益放大器在测控系统、智能仪器仪表等许多领域都有重要应用。本设计主要由直流稳压电源、集成运算放大器、多路模拟开关CD4051、反馈电阻网络等单元构成。程控增益放大器可以广泛地应用于数据采集系统、自动增益控制系统、动态范围扩展、远程检测仪和其他公共场所。     

一种低频模拟量输入通道的程控电路

1 引言在设计对多路低频小幅值交变信号进行测量的智能仪表系统时,为减小测量误差,简化硬件结构,提高通用性及灵活性,有必要在输入通道中设置程控增益放大器和程控截止频率滤波器。目前市售程控放大器增益分档少(仅能按2~n进行增益分档),有时难以满足使用要求。本文给出一种由8031单片机控制,采用数模转     

基于Multisim10和AD603的程控增益放大器仿真研究

本文在分析程控增益放大器AD603器件的性能中使用了MULTISIM 10电路仿真软件,给出了该器件的仿真电路、参数设置和步骤、结论,对于应用电路仿真软件进行程控增益放大器仿真研究提供了参考。     

宽频二阶程控低通滤波器的设计

设计了一种宽频二阶程控低通滤波器.二阶低通滤波电路由模拟乘法器、电流反馈运算放大器、可编程电阻网络及电容构成,充分利用了模拟乘法器和电流反馈运算放大器的优点,并通过主控电路调节数模转换电路的输出电压和低通滤波电路可编程电阻网络的值,实现截止频率程控.该滤波器具有截止频率高、信号处理范围宽、速度高等特点.     

采用"回避精确增益法"设计高精度程控运放

针对“传统程控运放”和目前“集成数字程控运放”的局限性,提出一种新的程控运放设计方法。该方案采用普通运放、低精度“数字电位器”、模拟开关和电压基准芯片,完成了高精度“程控运放”的设计,从而回避运放的精确增益,不但增益级数可多可少,而且具体增益可通过改变外接电阻任意设定。此设计成本低、精度高、调试简单,尤其适合大批量产品的生产。     

海洋电场信号程控增益超低噪声采集系统设计

针对海洋电磁勘探中微弱动态电场信号的宽测量范围需求,提出了一种电场信号程控增益超低噪声采集(Programmable Gain Ultra-Low Noise Acquisition,PGULNA)方法,给出了系统设计实现.设计的程控增益超低噪声采集电路以低噪声运算放大器为核心,将D/A转换器内部电阻网络作为可编程反馈...     

程控滤波器（D题）设计报告—2007年全国大学生电子设计竞赛索尼杯奖

本系统由可控增益放大器、程控滤波器、椭圆滤波器和幅频特性测试仪四大部分组成。可控增益放大器部分以可变增益放大器AD603作为核心器件,实现了输出增益的动态调整;程控滤波器和椭圆滤波器采用集成开关电容滤波器芯片LTC1068构成,采用DDS技术产生可变时钟改变滤     

膜片钳放大器自动校准方法的研究

为解决由电子元器件本身误差造成的增益不准确以及探头反馈电阻的分布电容造成的频响不准确等问题,文章提出了一种由计算机控制膜片钳放大器的自动校准方案;该方案采用线性拟合、有效值法、最小二乘拟合法和迭代法等算法,通过计算机和数据采集卡对膜片钳放大器进行数字控制和检测,从而实现自动校准;实验结果证明,校准后的参数能真实表现元器件的特性,从而保证实验数据的正确性,使放大器精度得到了提高,频响的正确性也得到了保证.     

2^0—2^8阶码放大器

本文介绍一种增益为２＾０～２＾８倍的阶码放大器的设计思想,该放大器选用新型的程控放大器为主放大器,采用类似ＦＬＡＳＨ Ａ／Ｄ转换器的原理来对瞬时信号子样比较,编码,再控制程控放大器对信号进行放大,以;实现扩大放大器功态范围的目的。     

大动态范围高精度AFE程控调理的经典实现方法

工程实践对数据采集系统提出了越来越高的要求：大动态输入范围、高精度、自动控制等；文章分析了影响数据采集系统性能指标的两大主要因素：ADC转换位数和ADC模拟信号输入的动态范围，从实现ADC最佳输入范围出发，基于PGA（程控增益放大器）、DCP（数控电位）、PGAF（程控增益放大器和滤波器）等新器件技术，提出了大动态范围、高精度AFE（模拟前端）程控调理的经典实现方法；为提高系统精度，简要探讨了实现系统自动校准（包括自动凋零和自动标定）的方法和其它一些抑制噪声的措施，在测控领域具有广泛的适用性和可移植性。     

Assessing Ideational and Evaluative Skills and Creative Styles and Attitudes

This article describes the rationale for the multiphase creative problem solving process, and reports the findings from an empirical investigation conducted to facilitate the problem solving of managers. The ideational skills of the managers were assessed before and after training in a complete process of creative problem solving, along with their ideational attitudes, creative problem solving style (i.e., generator, conceptualizer, optimizer, or implementor), and evaluative skill (i.e., ability to recognize original ideas). The most important findings indicated that the training had a significant impact on the evaluative accuracy of the managers. They were significantly more accurate in their judgments about original ideas after training, both in their identification of original ideas and their recognition of unoriginal ideas. After training, the managers also gave more solutions and more original solutions to problems. Finally, several variables (e.g., the “preference for active divergence” attitude, and the conceptualizer process style) seemed to moderate the impact of training. Training was therefore effective, with specific effects that can be predicted from pre-training individual differences in attitudes and process style.     

Rank and select revisited and extended

The deep connection between the Burrows–Wheeler transform (BWT) and the so-called rank and select data structures for symbol sequences is the basis of most successful approaches to compressed text indexing. Rank of a symbol at a given position equals the number of times the symbol appears in the corresponding prefix of the sequence. Select is the inverse, retrieving the positions of the symbol occurrences. It has been shown that improvements to rank/select algorithms, in combination with the BWT, turn into improved compressed text indexes.     

Semantics and verification of monitors and systems of monitors and processes

In this paper we present a sound and complete semantics for the monitor concept of C.A.R. Hoare. First a method for specification of monitors, introduced by O.-J. Dahl, is reviewed. This method is based on the relation between the historic sequence of monitor procedure calls and the historic sequence of monitor procedure exits. Based on such specifications and our new monitor semantics we present a method by which it is possible to prove that a concrete monitor is an implementation of an abstract one. In the last part of the paper an axiomatic semantics for systems of concurrent processes and monitors is introduced. The method supports verification by separation of concerns: Properties of the communication to and from each process are proven in isolation by a usual Hoare style axiomatic semantics, while abstract monitors are also specified in isolation by the method reviewed in the first part of the paper. These properties of the components of the system are then used in a new proof rule to conclude properties of the complete system. Stein Gjessing received a Ph.D. (actually a Dr. philos.) from the University of Oslo (Norway) in 1985. Presently he is an Associate Professor at the Institute of informatics, University of Oslo, Norway. Dr. Gjessings research interests are in the area of concurrent and distributed programming, operating systems, formal specification and verification and programming languages.     

Integrating and automating analysis and optimization

The development of an interface coupling program on personal computers for an analysis software system such as ANSYS, SAP, etc. and an optimization software system, MOST, is presented. By controlling and directing the communications the interface coupler integrates the two programs while retaining their versatility and interactive features. The integrated system is used to solve a numerical example of active noise control for a three-dimensional enclosure, in which an energy density level of control points is minimized by adding the sound source to cancel the unwanted noise. The interface coupling program automates with relatively low cost the iterative process for designing an engineering system, remaining flexible in acoustical modelling and efficient in equation solving. Also, the coupling interface is developed in a general-purpose way so that it can be expanded easily to integrate more analysis software packages of different kinds.