Photodiodes can be broken into two categories: largearea photodiodes with their attendant high capacitance(30pF to 3000pF) and smaller area photodiodes withrelatively low capacitance (10pF or less). For optimalsignal-to-noise performance, a transimpedance amplifi erconsisting of an inverting op amp and a feedback resistoris most commonly used to convert the photodiode currentinto voltage. In low noise amplifi er design, large areaphotodiode amplifi ers require more attention to reducingop amp input voltage noise, while small area photodiodeamplifi ers require more attention to reducing op amp inputcurrent noise and parasitic capacitances.
上传时间: 2013-10-28
上传用户:hanbeidang
PID控制器由比例单元(P)、积分单元(I)和微分单元(D)组成。其输入e (t)与输出u (t)的关系为 u(t)=kp[e(t)+1/TI∫e(t)dt+TD*de(t)/dt] 式中积分的上下限分别是0和t 因此它的传递函数为:G(s)=U(s)/E(s)=kp[1+1/(TI*s)+TD*s] 其中kp为比例系数; TI为积分时间常数; TD为微分时间常数.
上传时间: 2013-11-04
上传用户:jiiszha
本应用指南介绍了Pierce振荡器的基本知识,并提供一些指导作法来帮助用户如何规划一个好的振荡器设计,如何确定不同的外部器件的具体参数以及如何为振荡器设计一个良好的印刷电路板。
上传时间: 2013-11-06
上传用户:huxiao341000
High input impedance and a wide input range are twohighly desirable features in a precision analog-to-digitalconverter, and the LTC®2449 delta-sigma ADC has both.With just a few external components, the LTC2449 formsan exceptional measurement system with very high inputimpedance and an input range that extends 300mV beyondthe supply rails.
上传时间: 2013-11-02
上传用户:ywcftc277
Many thermal metrics exist for integrated circuit (IC) packages ranging from θja to Ψjt.Often, these thermal metrics are misapplied by customers who try to use them to estimate junction temperatures in their systems.
上传时间: 2013-10-18
上传用户:猫爱薛定谔
PLC 控制系统最初被应用于对离散量的控制,随着技术的发展和实际工程应用的需求,PLC 控制系统也开始用于对连续变量的控制。结合实际工程,对PID 模块指令在Allen2Bradley 公司的PLC 产品中的应用,进 行阐述说明。
上传时间: 2013-10-18
上传用户:小宝爱考拉
Digital-to-analog converters (DACs) are prevalent inindustrial control and automated test applications.General-purpose automated test equipment often requiresmany channels of precisely controlled voltagesthat span several voltage ranges. The LTC2704 is ahighly integrated 16-bit, 4-channel DAC for high-endapplications. It has a wide range of features designed toincrease performance and simplify design.
上传时间: 2013-11-22
上传用户:元宵汉堡包
PID由于用途广泛、使用灵活,已有系列化产品,使用中只需设定三个参数(Kp, Ti和Td)即可。在很多情况下,并不一定需要全部三个单元,可以取其中的一到两个单元,但比例控制单元是必不可少的。
上传时间: 2013-11-21
上传用户:gxrui1991
Designers of signal receiver systems often need to performcascaded chain analysis of system performancefrom the antenna all the way to the ADC. Noise is a criticalparameter in the chain analysis because it limits theoverall sensitivity of the receiver. An application’s noiserequirement has a signifi cant infl uence on the systemtopology, since the choice of topology strives to optimizethe overall signal-to-noise ratio, dynamic range andseveral other parameters. One problem in noise calculationsis translating between the various units used by thecomponents in the chain: namely the RF, IF/baseband,and digital (ADC) sections of the circuit.
上传时间: 2014-12-05
上传用户:cylnpy
PID(比例-积分-微分)控制器作为最早实用化的控制器已有70多年历史,现在仍然是应用最广泛的工业控制器。PID控制器简单易懂,使用中不需精确的系统模型等先决条件,因而成为应用最为广泛的控制器。
上传时间: 2013-11-24
上传用户:haohao