18位、线性、低噪声、精密双极性±10V直流电压源

<正>电路功能与优势图1所示电路提供18位可编程电压,其输出范围为-10 V～+10 V,同时积分非线性为±0.5 LSB、微分非线性为±0.5 LSB,并且具有低噪声特性。     

20bit线性低噪声精密单极性+10V直流电压源

电路功能与优势图1所示电路是一个20 bit线性、低噪声、精密单极性(+10 V)电压源,所需外部元件的数量极少.AD5790是一款20 bit、无缓冲电压输出DAC,采用最高33 V的双极性电源供电.正基准电压输入范围为5 V～ VDD-2.5V,负基准电压输入范围为VSS+2.5 V～0 V.两路基准电压输入均在片内缓冲,无需外部缓冲.相对精度最大值为±2 LSB,保证工作单调性,微分非线性(DNL)最大值为-1 LSB～+2 LSB.     

V/F和F/V转换器TD650原理与应用

<正> TD650是高精度高频型单片集成电压频率(V/F)和频率电压(F/V)转换电路。主要特点有:1.工作频率高,最高工作频率可达1MHz。2.非线性和温漂低。满度输出频率为10KHz 时,非线性度典型值为0.002%,最大值为0.005%,温漂小于±75ppm/℃。3.输入电压范围大,输入方式可以是单极性、双极性、差动输入电压或单极性输入电流。4.频率输出采用输出管集电极开路输出,其上拉电阻可接+30V、+15V 或+5V 电源,并可与TTL或CMOS 电路兼容。     

光电隔离高压驱动器

<正> 本文所述电路能从一个5V CMOS 逻辑电路取得输入信号,并输出一个具有相同极性的高压。这个高压电源可以在±30V～±150V 之间变化,而毋须更换电路元件。输入电压信号加在晶体管TR1和TR2的栅极上。     

低成本、16位、250kS/s、8通道、隔离数据采集系统(CN0254)

<正>电路功能与优势图1所示电路是高性价比、高度集成的16位、250 kS/s、8通道数据采集系统,可对±10 V工业级信号进行数字化转换。该电路还可在测量电路与主机控制器之间提供2 500 Vrms隔离,整个电路采用隔离式PWM控制5 V单电源供电。     

金升阳公司推出最新DC／DC模块电源

广州金升阳科技有限公司DC／DC模块电源产品一直受到广大客户的一致好评，近期推出1500VDC隔离宽压电源新品种：VRB-LD-15W，专门针对线路板上分布式电源系统中需要产生一组与输入电源隔离的单输出电源的应用场合而设计的。该产品输入电压允许变化范围宽（2：1），内置多种保护电路，可持续短路，自恢复，输出电压稳定度和输出纹波噪声要求较高：Trim端可使输出电压变化±10％V0。     

DDZⅢ型仪表开方单元专用模块KF43简介

<正>本模块专为DDZⅢ开方单元设计,使仪表组装简单、调试方便性能一致性好.外加少量元件即可组成开方器、开方积算器.1.原理框图 输入(V_i)→电平移动计算→开方运算→电平移动计算功放→输出(V_0)2.传递函数:V_0=2(Vi-1)~(1/2)+13.本模块带小信号切除,精度为±(0.1%～0.3%),尺寸:50mm×50mm,系统精度达到:输入电压≥1.09V时±0.5%输入电压<1.09V≥1.04V时±1%输入电压<1.04V时不计精度为合格     

CF741在超共模电压范围下的工作

<正> 集成运放可以工作在一定的共模电压下。但如果共模电压超过其允许值,运放将因输入级偏置电路趋于饱和或截止状态而无法正常工作。对741型通用运算放大器,在电源电压为±15V时其共模电压范围的典型值为±13V。当共模电压V_(CM)降低至与负电源电压V_相等、即V_(IN+)=V_(IN_)=-15V时,GF741将失去     

仿真机模拟I/O ADC接口设计

本文①针对仿真机模拟I/O多路ADC工作时的特殊要求设计了四种控制方式。②为了减小外部共模干扰设计了差分放大器作为ADC输入前的测量输入放大器。③为了使±10V及±100V两种输入量程可以工作,设计了量程输入放大器。     

国防科技大学研究生院一九九一年硕士生入学考试数字电路与模拟电路试题

<正> (1—10题,每题10分) 一、①电路如图1 a) b) c)所示,输入V_i为正弦波信号,峰值为±5V,试分别画出V_i与V_o的对应波形,并标出电平值。(说明:设图1中全部稳压二极管稳压电压V_z=5V。)     

Hyperbolic regression analysis for kinetics, electrophoresis, ELISA, RIA, Bradford, Lowry, and other applications

Hyperbolic regression analysis is an effective method for fitting experimental data points obtained from a variety of experiments in molecular biology, including enzyme kinetics, agarose gel electrophoresis of DNA fragments, SDS-polyacrylamide gel electrophoresis of proteins, enzyme-linked immunosorbent assays (ELISA), radioimmunoassays (RIA), Bradford protein quantitation assays, Lowry protein assays, and other applications. Hyperbolic regression yields excellent fitted curves without the biases that are introduced by carrying out linear regression on double reciprocal coordinates, and it produces one simple equation, encompassing all the data points, that can be used easily in a pocket calculator to estimate the values of unknown samples from the known standards.     

Pointcuts, advice, refinements, and collaborations: similarities, differences, and synergies

Aspect-oriented programming (AOP) is a novel programming paradigm that aims at modularizing complex software. It embraces several mechanisms including (1) pointcuts and advice as well as (2) refinements and collaborations. Though all these mechanisms deal with crosscutting concerns, i.e., a special class of design and implementation problems that challenge traditional programming paradigms, they do so in different ways. In this article we explore their relationship and their impact on modularity, which is an important prerequisite for reliable and maintainable software. Our exploration helps researchers and practitioners to understand their differences and exposes which mechanism is best used for which problem.     

Texture,contour, shape,and motion

Intrinsic magic calculation exploits constraints arising from physical and imaging processes to derive physical scene parameters from input images. After a brief review of a paradigmatic intrinsic image calculation we turn to a recent result in shape from texture and then to a new result that derives shape and motion from a sequence of patterned inputs. Experimental results are demonstrated for synthetic and natural images.     

基于模糊PID参数自整定的细胞培养箱温度控制算法

针对细胞培养箱温度控制具有非线性、时滞性、易受干扰且难以建立精确的数学模型的特点,传统的PID控制方法对于快速维持系统箱内温度稳定存在一定的局限性。提出了以温度误差和误差变化率为控制输入,培养箱内温度为控制量的模糊PID参数自整定的温度控制算法,实现了对PID参数的实时在线修正。实验表明,该模糊PID参数自整定温度控制算法,温度从26℃上升到目标温度37℃,建立稳态的时间为2890s,温度超调极小。系统温度控制精度为±0.05℃,并在相同型号的细胞培养箱上同样得到验证。在控制稳定性方面获得了比传统PID控制更好的控温效果,稳定快,极小超调,温度控制精度高,能满足细胞培养箱温度控制的要求。