The Reactor design pattern handles service requests that are delivered concurrently to an application by one or more clients. Each service in an application may consist of serveral methods and is represented by a separate event handler that is responsible for dispatching service-specific requests.
上传时间： 2013-10-15
上传用户：libinxny
This application note describes a Linear Technology "Half-Flash" A/D converter, the LTC1099, being connected to a 256 element line scan photodiode array. This technology adapts itself to handheld (i.e., low power) bar code readers, as well as high resolution automated machine inspection applications..
上传时间： 2013-11-21
上传用户：lchjng
Power conversion by virtue of its basic role produces harmonics due to theslicing of either voltages or currents. To a large extent the pollution in theutility supply and the deterioration of the power quality has been generatedor created by non-linear converters. It is therefore ironic that power convertersshould now be used to clean up the pollution that they helped to create inthe first place.In a utility system, it is desirable to prevent harmonic currents (which resultin EMI and resonance problems) and limit reactive power flows (whichresult in transmission losses).Traditionally, shunt passive filters, comprised of tuned LC elements andcapacitor banks, were used to filter the harmonics and to compensate forreactive current due to non-linear loads. However, in practical applicationsthese methods have many disadvantages.
上传时间： 2013-11-05
上传用户：AISINI005
开关在电路中起接通信号或断开信号的作用。最常见的可控开关是继电器，当给驱动继电器的驱动电路加高电平或低电平时，继电器就吸合或释放，其触点接通或断开电路。CMOS模拟开关是一种可控开关，它不象继电器那样可以用在大电流、高电压场合，只适于处理幅度不超过其工作电压、电流较小的模拟或数字信号。 一、常用CMOS模拟开关引脚功能和工作原理 1.四双向模拟开关CD4066 CD4066 的引脚功能如图1所示。每个封装内部有4个独立的模拟开关，每个模拟开关有输入、输出、控制三个端子，其中输入端和输出端可互换。当控制端加高电平时，开关导通；当控制端加低电平时开关截止。模拟开关导通时，导通电阻为几十欧姆；模拟开关截止时，呈现很高的阻抗，可以看成为开路。模拟开关可传输数字信号和模拟信号，可传输的模拟信号的上限频率为40MHz。各开关间的串扰很小，典型值为－50dB。
上传时间： 2013-10-27
上传用户：bibirnovis
铝电解电容器：详细介绍原理，应用，使用技巧 电容器(capacitor)在音响组件中被广泛运用，滤波、反交连、高频补偿、直流回授...随处可见。但若依功能及制造材料、制造方法细分，那可不是一朝一夕能说得明白。所以缩小范围，本文只谈电解电容，而且只谈电源平滑滤波用的铝质电解电容。 每台音响机器都要吃电源─除了被动式前级，既然需要供电，那就少不了「滤波」这个动作。不要和我争，采用电池供电当然无必要电源平滑滤波。但电池充电电路也有整流及滤波，故滤波电容器还是会存在。 我们现在习用的滤波电容，正式的名称应是：铝箔干式电解电容器。就我的观察，除加拿大Sonic Frontiers真空管前级，曾在高压稳压线路中选用PP塑料电容做滤波外，其它机种一概都是采用铝箔干式电解电容；因此网友有必要对它多做了解。 面对电源稳压线路中担任电源平滑滤波的电容器，你首先想到的会是什幺？─容量？耐压？电容器的封装外皮上一定有容量标示，那是指静电容量；也一定有耐压标示，那是指工作电压或额定电压。 工作电压(working voltage)简称WV，为绝对安全值；若是surge voltage(简称SV或Vs)，就是涌浪电压或崩溃电压;，超过这个电压值就保证此电容会被浪淹死─小心电容会爆！根据国际IEC 384-4规定，低于315V时，Vs=1.15×Vr，高于315V时，Vs=1.1×Vr。Vs是涌浪电压，Vr是额定电压(rated voltage)。
上传时间： 2013-12-23
上传用户：gundan
Finite state machines are widely used in digital circuit designs. Generally, when designing a state machine using an HDL, the synthesis tools will optimize away all states that cannot be reached and generate a highly optimized circuit. Sometimes, however, the optimization is not acceptable. For example, if the circuit powers up in an invalid state, or the circuit is in an extreme working environment and a glitch sends it into an undesired state, the circuit may never get back to its normal operating condition.
标签： Creating Machines Mentor State
上传时间： 2013-10-08
上传用户：wangzhen1990
Calculation of the Differential Impedance of Tracks on FR4 substrates There is a discrepancy between calculated and measured values of impedance for differential transmission lineson FR4. This is especially noticeable in the case of surface microstrip configurations. The anomaly is shown tobe due to the nature of the substrate material. This needs to be considered as a layered structure of epoxy resinand glass fibre. Calculations, using Boundary Element field methods, show that the distribution of the electricfield within this layered structure determines the apparent dielectric constant and therefore affects theimpedance. Thus FR4 cannot be considered to be uniform dielectric when calculating differential impedance.
上传时间： 2014-12-24
上传用户：DE2542
Abstract: The rapid build out of today's smart grid raises a number of security questions. In this article,we review two recent well-documented security breaches and a report of a security gap. These situationsinclude a 2009 smart-meter hack in Puerto Rico; a 2012 password discovery in grid distributionequipment; and insecure storage of a private key in distribution automation equipment. For each of theseattacks, we examine the breach, the potential threat, and secure silicon methods that, as part of acomplete security strategy, can help thwart the attacks.
上传时间： 2013-10-27
上传用户：tecman
Abstract: It may sound trite, but it is definitely true: the smart grid has the potential to completely transform the energyindustry. However, smart meters and grid management alone will not ensure the success of the smart grid. Unliketraditional IT networks, smart grids require consideration of energy measurement and security. To completely optimize thistechnology, smart grid designs must focus on energy measurement and security. This tutorial considers the benefits ofboth energy measurement and security and how they make machine-to-machine networks different from traditional IT.
上传时间： 2013-10-29
上传用户：皇族传媒
Photomultipliers (PMT), avalanche photodiodes (APD),ultrasonic transducers, capacitance microphones, radiationdetectors and similar devices require high voltage,low current bias. Additionally, the high voltage must bepristinely free of noise; well under a millivolt is a commonrequirement with a few hundred microvolts sometimesnecessary. Normally, switching regulator confi gurationscannot achieve this performance level without employingspecial techniques. One aid to achieving low noise is thatload currents rarely exceed 5mA. This freedom permitsoutput fi ltering methods that are usually impractical
上传时间： 2013-10-28
上传用户：lhw888
