，对一般速度较快的ttl电路，其印制线条长于10cm以上时就应采用终端匹配措施。匹配电阻的阻值应根据
dui yi ban su du jiao kuai de ttl dian lu qi yin zhi xian tiao chang yu 10cm yi shang shi jiu ying cai yong zhong duan pi pei cuo shi pi pei dian zu de zu zhi ying gen ju
采用慢速电路。必要时可加终端匹配，即在传输线的末端对地和电源端各加接一个相同阻值的匹配电阻。根据经验
cai yong man su dian lu bi yao shi ke jia zhong duan pi pei ji zai chuan shu xian de mo duan dui di he dian yuan duan ge jia jie yi ge xiang tong zu zhi de pi pei dian zu gen ju jing yan
。3.抑制反射干扰为了抑制出现在印制线条终端的反射干扰，除了特殊需要之外，应尽可能缩短印制线的长度和
3. yi zhi fan she gan rao wei le yi zhi chu xian zai yin zhi xian tiao zhong duan de fan she gan rao chu le te shu xu yao zhi wai ying jin ke neng suo duan yin zhi xian de chang du he
置地回路，因为后者常载有高频电流。●在印制板布置高速、中速和低速逻辑电路时，应按照图1的方式排列器件
zhi di hui lu yin wei hou zhe chang zai you gao pin dian liu zai yin zhi ban bu zhi gao su zhong su he di su luo ji dian lu shi ying an zhao tu 1 de fang shi pai lie qi jian
紧紧挨着连接器。●数据总线的布线应每两根信号线之间夹一根信号地线。最好是紧紧挨着最不重要的地址引线放
jin jin ai zhe lian jie qi shu ju zong xian de bu xian ying mei liang gen xin hao xian zhi jian jia yi gen xin hao di xian zui hao shi jin jin ai zhe zui bu zhong yao de di zhi yin xian fang
靠近，驱动器应紧挨着连接器。●总线驱动器应紧挨其欲驱动的总线。对于那些离开印制电路板的引线，驱动器应
kao jin qu dong qi ying jin ai zhe lian jie qi zong xian qu dong qi ying jin ai qi yu qu dong de zong xian dui yu na xie li kai yin zhi dian lu ban de yin xian qu dong qi ying
变，导线的拐角360度安全卫士应大于90度禁止环状走线等。●时钟信号引线最容易产生电磁辐射干扰，走线时应与地线回路相
bian dao xian de guai jiao 360 du an quan wei shi ying da yu 90 du jin zhi huan zhuang zou xian deng shi zhong xin hao yin xian zui rong yi chan sheng dian ci fu she gan rao zou xian shi ying yu di xian hui lu xiang
生的电磁辐射，在印制电路板布线时，还应注意以下几点：●尽量减少印制导线的不连续性，例如导线宽度不要突
sheng de dian ci fu she zai yin zhi dian lu ban bu xian shi hai ying zhu yi yi xia ji dian jin liang jian shao yin zhi dao xian de bu lian xu xing li ru dao xian kuan du bu yao tu
对干扰十分敏感的信号线360度安全卫士之间设置一根接地的印制线，可以有效地抑制串扰。为了避免高频信号通过印制导线时产
dui gan rao shi fen min gan de xin hao xian 360 du an quan wei shi zhi jian she zhi yi gen jie di de yin zhi xian ke yi you xiao di yi zhi chuan rao wei le bi mian gao pin xin hao tong guo yin zhi dao xian shi chan
线时应尽量避免长距离的平等走线，尽可能拉开线与线之间的距离，信号线与地线及电源线尽可能不交叉。在一些
xian shi ying jin liang bi mian chang ju li de ping deng zou xian jin ke neng la kai xian yu xian zhi jian de ju li xin hao xian yu di xian ji dian yuan xian jin ke neng bu jiao cha zai yi xie
的一面横向布线，另一面纵向布线，然后在交叉孔处用金属化孔相连。为了抑制印制板导线之间的串扰，在设计布
de yi mian heng xiang bu xian ling yi mian zong xiang bu xian ran hou zai jiao cha kong chu yong jin shu hua kong xiang lian wei le yi zhi yin zhi ban dao xian zhi jian de chuan rao zai she ji bu
导线电感，但导线之间的互感和分布电容增加，如果布局允许，最好采用360度安全卫士井字形网状布线结构，具体做法是印制板
dao xian dian gan dan dao xian zhi jian de hu gan he fen bu dian rong zeng jia ru guo bu ju yun hu zui hao cai yong 360 du an quan wei shi jing zi xing wang zhuang bu xian jie gou ju ti zuo fa shi yin zhi ban
于集成电路，印制导线宽度可在0.2～1.0mm之间选择。2. 采用正确的布线策略采用平等走线可以减少
yu ji cheng dian lu yin zhi dao xian kuan du ke zai 0.2 1.0mm zhi jian xuan ze 2. cai yong zheng que de bu xian ce lue cai yong ping deng zou xian ke yi jian shao
变电流，印制导线要尽可能地短。对于分立元件电路，印制导线宽度在1.5mm左右时，即360度安全卫士可完全满足要求；对
bian dian liu yin zhi dao xian yao jin ke neng di duan dui yu fen li yuan jian dian lu yin zhi dao xian kuan du zai 1.5mm zuo you shi ji 360 du an quan wei shi ke wan quan man zu yao qiu dui
宽度成反比，因而短而精的导线对抑制干扰是有利的。时钟引线、行驱动器或总线驱动器的信号线常常载有大的瞬
kuan du cheng fan bi yin er duan er jing de dao xian dui yi zhi gan rao shi you li de shi zhong yin xian hang qu dong qi huo zong xian qu dong qi de xin hao xian chang chang zai you da de shun
要是由印制导线的电感成分造成的，因此应尽量减小印制导线的电感量。360度安全卫士印制导线的电感量与其长度成正比，与其
yao shi you yin zhi dao xian de dian gan cheng fen zao cheng de yin ci ying jin liang jian xiao yin zhi dao xian de dian gan liang 360 du an quan wei shi yin zhi dao xian de dian gan liang yu qi chang du cheng zheng bi yu qi
子设备本身对其它电子设备的电磁干扰。1.选择合理的导线宽度由于瞬变电流在印制线条上所产生的冲击干扰主
zi she bei ben shen dui qi ta dian zi she bei de dian ci gan rao 1. xuan ze he li de dao xian kuan du you yu shun bian dian liu zai yin zhi xian tiao shang suo chan sheng de chong ji gan rao zhu
计的360度安全卫士目的是使电子设备既能抑制各种外来的干扰，使电子设备在特定的电磁环境中能够正常工作，同时又能减少电
ji de 360 du an quan wei shi mu de shi shi dian zi she bei ji neng yi zhi ge zhong wai lai de gan rao shi dian zi she bei zai te ding de dian ci huan jing zhong neng gou zheng chang gong zuo tong shi you neng jian shao dian
电磁兼容性设计 电磁兼容性是指电子设备在各种电磁环境中仍能够协调、有效地进行工作的能力。电磁兼容性设
dian ci jian rong xing she ji dian ci jian rong xing shi zhi dian zi she bei zai ge zhong dian ci huan jing zhong reng neng gou xie diao you xiao di jin hang gong zuo de neng li dian ci jian rong xing she