CSS-323R中文资料

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边框：border-style none ：无轮廓。

border-color 与border-width 将被忽略,hidden ：隐藏边框。

dotted ：点状轮廓。

dashed ：虚线轮廓。

solid ：实线轮廓double ：双线轮廓。

两条单线与其间隔的和等于指定的border-width 值,groove ：3D 凹槽轮廓。

ridge ：3D 凸槽,轮廓。

inset ：3D 凹边轮廓。

outset ：3D 凸边轮廓。

border-radius ： 设置对象使用圆角边框 <length>：用长度值设置对象的圆角半径长度。

不允许负值 <percentage>：用百分比设置对象的圆角半径长度。

不允许负值 这两个对象一般为10px ；border-top-right-radiu s设置对象右上角圆角边框 border-top-left-radius 设置对象左上角圆角边框 border-bottom-left-rad ius设置对象左下角圆角边框border-bottom-right-ra dius 设置对象右下角圆角边框背景：属性 简介background 复合属性。

设置对象的背景特性 background-color 设置对象的背景颜色background-image设置对象的背景图像none ：无背景图。

<url>：使用绝对或相对地址指定背景图像。

background-repeat 设置对象的背景图像如何铺排填充repeat-x ：背景图像在横向上平铺 repeat-y ：背景图像在纵向上平铺 repeat ：背景图像在横向和纵向平铺 no-repeat ：背景图像不平铺 round ：背景图像自动缩放直到适应且填充满整个容器。

（CSS3）space ：背景图像以相同的间距平铺且填充满整个容器或某个方向。

（CSS3）background-attachment 设置对象的背景图像是随对象内容滚动还是固定的fixed ：背景图像相对于窗体固定。

H.323协议简介在传统电话系统中，一次通话从建立系统连接到拆除连接都需要一定的信令来配合完成。

同样，在IP电话中，如何寻找被叫方、如何建立应答、如何按照彼此的数据处理能力发送数据，也需要相应的信令系统，一般称为协议。

目前在国际上，比较有景响的IP电话方面的协议包括ITU-T提出的H.323协议和IETE提出的SIP协议，本节主要介绍目前用得最广泛H.323协议。

一、H.323的体系结构为了能在不保证QoS的分组交换网络上展开多媒体会议，由ITU的第15研究组SG-15于1996年通过H.323建议的第一版，并在1998年提出了H.323的第二版。

H.323制定了无QoS（服务质量）保证的分组网络PBN（packet Based Networks）上的多媒体通信系统标准，这些分组网络主宰了当今的桌面网络系统，包括基于TCP/IP、IPX分组交换的以太网、快速以太网、令牌网、FDDI技术。

因此，H.323标准为LAN、WAN、Internet、因特网上的多媒体通信应用提供了技术基础和保障。

H.323是ITU多媒体通信系列标准H.32x的一部份，该系列标准使得在现有通信网络上进行视频会议成为可能，其中，H.320是在N-ISDN上进行多媒体通信的标准：H.321是在B-ISDN上进行多媒体通信的标准：H.322是在有服务质量保证的LAN上进行多媒体通信的标准：H.324是在GSTN和无线网络上进行多媒体通信的标准。

H.323为现有的分组网络PBN（如IP网络）提供多媒体通信标准。

若和其它的IP技术如IETF的资源预留协议RSVP相结合，就可以实现IP网络的多媒体通信。

基于IP的LAN正变得越来越强大，如IP over SDH/SONET、IP over ATM技术正在快速发展以及LAN 宽带正在不断的提高。

由于能提供设备与设备、应用与应用、供应商与供应商之间的互操作能力，因此，H.323能够保证所有H.323兼容设备的互操作性。

LM123/LM323A/LM3233-Amp,5-Volt Positive RegulatorGeneral DescriptionThe LM123is a three-terminal positive regulator with a pre-set 5V output and a load driving capability of 3amps.New circuit design and processing techniques are used to provide the high output current without sacrificing the regulation characteristics of lower current devices.The LM323A offers improved precision over the standard LM323.Parameters with tightened specifications include output voltage tolerance,line regulation,and load regulation.The 3amp regulator is virtually blowout proof.Current limit-ing,power limiting,and thermal shutdown provide the same high level of reliability obtained with these techniques in the LM1091amp regulator.No external components are required for operation of the LM123.If the device is more than 4inches from the filter ca-pacitor,however,a 1µF solid tantalum capacitor should be used on the input.A 0.1µF or larger capacitor may be used on the output to reduce load transient spikes created by fast switching digital logic,or to swamp out stray load capaci-tance.An overall worst case specification for the combined effects of input voltage,load currents,ambient temperature,and power dissipation ensure that the LM123will perform satis-factorily as a system element.For applications requiring other voltages,see LM150series adjustable regulator data sheet.Operation is guaranteed over the junction temperature range −55˚C to +150˚C for LM123,−40˚C to +125˚C for LM323A,and 0˚C to +125˚C for LM323.A hermetic TO-3package is used for high reliability and low thermal resistance.Featuresn Guaranteed 1%initial accuracy (A version)n 3amp output currentn Internal current and thermal limiting n 0.01Ωtypical output impedance n 7.5V minimum input voltage n 30W power dissipationnP +Product Enhancement testedConnection DiagramTypical ApplicationsMetal Can PackageDS007771-2Order Number LM123K STEEL,LM323AK STEEL or LM323K STEELSee NS Package Number K02A Order Number LM123K/883See NS Package Number K02CBasic 3Amp RegulatorDS007771-3*Required if LM123is more than 4"from filter capacitor.†Regulator is stable with no load capacitor into resistive loads.April 1998LM123/LM323A/LM3233-Amp,5-Volt Positive Regulator©1999National Semiconductor Corporation Absolute Maximum Ratings(Note1)If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.(Note5)Input Voltage20V Power Dissipation Internally Limited Operating Junction Temperature RangeLM123−55˚C to+150˚C LM323A−40˚C to+125˚C LM3230˚C to+125˚C Storage Temperature Range−65˚C to+150˚C Lead Temperature(Soldering,10sec.)300˚C ESD Tolerance(Note5)2000VLM123Electrical Characteristics(Note2)Parameter Conditions LM123UnitsMin Typ Max Output Voltage T j=25˚C 4.75 5.3VV IN=7.5V,I OUT=0A7.5V≤V IN≤15V 4.6 5.4V0A≤I OUT≤3A,P≤30WLine Regulation(Note4)T j=25˚C525mV7.5V≤V IN≤15VLoad Regulation(Note4)T j=25˚C,V IN=7.5V,25100mV0A≤I OUT≤3AQuiescent Current7.5V≤V IN≤15V,1220mA0A≤I OUT≤3AOutput Noise Voltage T j=25˚C40µVrms10Hz≤f≤100kHzShort Circuit Current Limit T j=25˚CV IN=15V3 4.5AV IN=7.5V45A Long Term Stability35mV Thermal Resistance Junctionto Case(Note3)2˚C/W LM323A/LM323Electrical Characteristics(Note2)Parameter Conditions LM323A LM323UnitsMin Typ Max Min Typ MaxOutput Voltage T j=25˚C 4.955 5.05 4.85 5.2VV IN=7.5V,I OUT=0A7.5V≤V IN≤15V 4.85 5.15 4.75 5.25V0A≤I OUT≤3A,P≤30WLine Regulation(Note4)T j=25˚C510525mV7.5V≤V IN≤15VLoad Regulation(Note4)T j=25˚C,V IN=7.5V,255025100mV0A≤I OUT≤3AQuiescent Current7.5V≤V IN≤15V,12201220mA0A≤I OUT≤3AOutput Noise Voltage T j=25˚C4040µVrms10Hz≤f≤100kHzShort Circuit Current Limit T j=25˚CV IN=15V3 4.53 4.5AV IN=7.5V4645A Long Term Stability3535mV Thermal Resistance Junctionto Case(Note3)22˚C/W 2LM323A/LM323Electrical Characteristics(Note2)(Continued)Note1:“Absolute Maximum Ratings”indicate limits beyond which damage to the device may occur.Operating Ratings indicate conditions for which the device is functional,but do not guarantee specific performance limits.Note2:Unless otherwise noted,specifications apply for−55˚C≤T j≤+150˚C for the LM123,−40˚C≤T j≤+125˚C for the LM323A,and0˚C≤T j≤+125˚C for the LM323.Although power dissipation is internally limited,specifications apply only for P≤30W.Note3:Without a heat sink,the thermal resistance of the TO-3package is about35˚C/W.With a heat sink,the effective thermal resistance can only approach the specified values of2˚C/W,depending on the efficiency of the heat sink.Note4:Load and line regulation are specified at constant junction temperature.Pulse testing is required with a pulse width≤1ms and a duty cycle≤5%.Note5:Refer to RETS123K drawing for LM123K military specifications.Note6:Human body model,1.5kΩin series with100pF.Typical Performance CharacteristicsMaximum Average Power Dissipation for LM123DS007771-9Maximum Average PowerDissipation for LM323A,LM323DS007771-10Output ImpedanceDS007771-11Peak Available Output CurrentDS007771-12Short Circuit CurrentDS007771-13Ripple RejectionDS007771-14Dropout VoltageDS007771-15Line Transient ResponseDS007771-16Output VoltageDS007771-17 3Typical Performance Characteristics(Continued)Typical ApplicationsQuiescent CurrentDS007771-18Load Transient ResponseDS007771-19Output Noise VoltageDS007771-2010Amp Regulator with Complete Overload ProtectionDS007771-6 *Select for20mA Current from Unregulated Negative Supply4Typical Applications(Continued)Adjustable Regulator0V−10V@3ADS007771-7A1—LM101AC1—2µF Optional—Improves Ripple Rejection,Noise,and Transient ResponseTrimming Output to5VDS007771-8Adjustable Output5V−10V0.1%RegulationDS007771-4*Select to Set Output Voltage**Select to Draw25mA from V−5Schematic DiagramDS007771-1 6Physical Dimensions inches(millimeters)unless otherwise notedMetal Can Package(K)Order Number LM123K STEEL,LM323AK STEEL or LM323K STEELNS Package Number K02A7Physical Dimensionsinches (millimeters)unless otherwise noted (Continued)LIFE SUPPORT POLICYNATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION.As used herein:1.Life support devices or systems are devices or systems which,(a)are intended for surgical implant into the body,or (b)support or sustain life,and whose failure to perform when properly used in accordance with instructions for use provided in the labeling,can be reasonably expected to result in a significant injury to the user.2.A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system,or to affect its safety or effectiveness.National Semiconductor Corporation AmericasTel:1-800-272-9959Fax:1-800-737-7018Email:support@National Semiconductor EuropeFax:+49(0)180-5308586Email:europe.support@Deutsch Tel:+49(0)180-5308585English Tel:+49(0)180-5327832Français Tel:+49(0)180-5329358Italiano Tel:+49(0)180-5341680National Semiconductor Asia Pacific Customer Response Group Tel:65-2544466Fax:65-2504466Email:sea.support@National Semiconductor Japan Ltd.Tel:81-3-5639-7560Fax:81-3-5639-7507Metal Can Package (K)Mil-Aero ProductOrder Number LM123K/883NS Package Number K02CL M 123/L M 323A /L M 3233-A m p ,5-V o l t P o s i t i v e R e g u l a t o rNational does not assume any responsibility for use of any circuitry described,no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.。