器件的選用

器件的選用在設計的產品運行中起到至關重要的作用，從電機、開關
、繼電器、電纜組件及連接器等
，甚至到電源、晶振、bianyaqidengdouyinggaixiagongfujinxingjingxindishaixuan
，fouze
，zaixuanxingzhongshaoyoubushen
，jiuhuiduishebeizishenhuozhouweijiangshebeizaochengyanzhongdebuliyingxiang。diancijianrongshejicongsangefangmiankaolv：1)幹擾源；2)傳播耦合路徑；3)minganshebei。diancijianrongshejicongzhesangefangmianzuogongzuo。qizhonglvbolianjieqishijiejueouhelujingdejuejiafangfazhiyi。lvbolianjieshiyizhongjubeilvbogongnengdelianjieqi。tongchanggongchengshangshiyongdexinhaodianlanshipingbidianlan，danrengbunengmanzudiancijianrongbiaozhun
，duiyugaopinganraodepingbi，zhuyaoyuanyinshipingbidianlanshijinshubianzhiwang，shangmiandekongdonghuizaigaopinshichanshengxielu
，lingwaiyigeyuanyinshipingbidianlandegaopingbixiaonengqujueyudianlanpingbicengdeduanjieqingkuang，zhiyoudangdianlanpingbicengdeduanjiewei360dudizukangdajieshi，caihuiyoujiaolixiangdegaopingbixiaoguo
，henduochanghexiadouwufabaozheng。lvbolianjieqinenggouyouxiaodelvchububiyaodegaopinchengfen，mibulepingbidianlanduiyugaopinganraopingbidebuzu"。

電子設備的電磁兼容分析

電dian纜lan是shi係xi統tong的de最zui薄bo弱ruo環huan節jie
，兩liang台tai獨du立li進jin行xing電dian磁ci幹gan擾rao測ce試shi完wan全quan合he格ge的de設she備bei通tong過guo電dian纜lan連lian接jie後hou
，係xi統tong往wang往wang在zai電dian磁ci兼jian容rong環huan境jing下xia測ce試shi不bu通tong過guo，這zhe是shi忽hu略lve了le電dian纜lan的de輻fu射she作zuo用yong。實shi踐jian表biao明ming
，按an照zhao屏ping蔽bi設she計ji規gui範fan設she計ji的de屏ping蔽bi機ji箱xiang可ke達da到dao60～80dB的屏蔽效能
，電纜處置不當，造成係統產生嚴重的電磁幹擾問題。90％的(de)電(dian)磁(ci)幹(gan)擾(rao)問(wen)題(ti)是(shi)由(you)於(yu)電(dian)纜(lan)造(zao)成(cheng)的(de)。電(dian)纜(lan)是(shi)高(gao)效(xiao)的(de)電(dian)磁(ci)波(bo)接(jie)收(shou)天(tian)線(xian)和(he)輻(fu)射(she)天(tian)線(xian)

，電(dian)纜(lan)產(chan)生(sheng)的(de)輻(fu)射(she)尤(you)其(qi)嚴(yan)重(zhong)。電(dian)纜(lan)端(duan)口(kou)處(chu)有(you)共(gong)模(mo)電(dian)壓(ya)存(cun)在(zai)
，電(dian)纜(lan)在(zai)這(zhe)個(ge)共(gong)模(mo)電(dian)壓(ya)的(de)驅(qu)動(dong)下(xia)
，如(ru)同(tong)一(yi)根(gen)單(dan)極(ji)天(tian)線(xian)。它(ta)產(chan)生(sheng)的(de)電(dian)場(chang)輻(fu)射(she)如(ru)下(xia)式(shi)所(suo)示(shi)：

E=12．6×10-7(fIL)(1／r)

式中：J是電纜中的共模電流強度，L是電纜的長度
，
，是共模信號的頻率，rshiguancediandaofusheyuandejuli。ketongguojianxiaogaopingongmodianliuqiangdu

，suoduandianlanchangdujianxiaodianlandefushe。dianlandechangdubunengsuiyijianxiao，kongzhidianlangongmofushedezuihaodefangfashijianxiaogaopingongmodianliudefudu，yinweigaopingongmodianliudefushexiaolvhengao，shizaochengdianlanchaobiaofushedezhuyaoyinsu。jianxiaodianlanshanggongmogaopindianliudeyigeyouxiaofangfashizaidianlandeduankouchushiyongditonglvboqi
，lvchudianlanshangdegaopingongmodianliu。chuantongshangdoushijianglvboqianzhuangzaixianlubanshangdedianlanduankouchu，zhezhonganzhuangfangshijingguolvbohoudexinhaoxianzaijixiangneijiaochang，rongyizaiciganyingshangqianraoxinhao
，xingchengxindegongmodianliu，daozhidianlanfushe。zaiciganyingdexinhaoyoulianggelaiyuan：1)機箱內的電磁波會感應到電纜上
，2)濾(lv)波(bo)器(qi)前(qian)的(de)幹(gan)擾(rao)信(xin)號(hao)會(hui)通(tong)過(guo)寄(ji)生(sheng)電(dian)容(rong)直(zhi)接(jie)耦(ou)合(he)到(dao)電(dian)纜(lan)端(duan)口(kou)上(shang)。解(jie)決(jue)這(zhe)個(ge)問(wen)題(ti)的(de)方(fang)法(fa)是(shi)盡(jin)量(liang)減(jian)小(xiao)濾(lv)波(bo)後(hou)暴(bao)露(lu)在(zai)機(ji)箱(xiang)內(nei)導(dao)線(xian)長(chang)度(du)。濾(lv)波(bo)連(lian)接(jie)器(qi)是(shi)解(jie)決(jue)這(zhe)個(ge)問(wen)題(ti)的(de)理(li)想(xiang)器(qi)件(jian)。濾(lv)波(bo)連(lian)接(jie)器(qi)的(de)每(mei)個(ge)插(cha)針(zhen)上(shang)有(you)一(yi)個(ge)低(di)通(tong)濾(lv)波(bo)器(qi)，能(neng)夠(gou)將(jiang)插(cha)針(zhen)上(shang)的(de)共(gong)模(mo)電(dian)流(liu)濾(lv)掉(diao)。這(zhe)些(xie)濾(lv)波(bo)連(lian)接(jie)器(qi)往(wang)往(wang)在(zai)外(wai)形(xing)和(he)尺(chi)寸(cun)上(shang)與(yu)普(pu)通(tong)連(lian)接(jie)器(qi)相(xiang)同(tong)
，可(ke)以(yi)直(zhi)接(jie)替(ti)代(dai)普(pu)通(tong)連(lian)接(jie)器(qi)。由(you)於(yu)連(lian)接(jie)器(qi)安(an)裝(zhuang)在(zai)電(dian)纜(lan)進(jin)入(ru)機(ji)箱(xiang)的(de)端(duan)口(kou)處(chu)，因(yin)此(ci)濾(lv)波(bo)後(hou)的(de)導(dao)線(xian)不(bu)會(hui)再(zai)感(gan)應(ying)上(shang)幹(gan)擾(rao)信(xin)號(hao)。

濾波連接器較屏蔽電纜優點

濾波連接器較屏蔽電纜使用的優點有如下三個優點：1)濾(lv)波(bo)連(lian)接(jie)器(qi)能(neng)將(jiang)電(dian)纜(lan)中(zhong)的(de)幹(gan)擾(rao)電(dian)流(liu)濾(lv)除(chu)掉(diao)
，徹(che)底(di)消(xiao)除(chu)電(dian)纜(lan)的(de)輻(fu)射(she)因(yin)素(su)。屏(ping)蔽(bi)電(dian)纜(lan)僅(jin)僅(jin)是(shi)防(fang)止(zhi)幹(gan)擾(rao)通(tong)過(guo)電(dian)纜(lan)輻(fu)射(she)，實(shi)際(ji)這(zhe)些(xie)幹(gan)擾(rao)電(dian)流(liu)還(hai)在(zai)電(dian)纜(lan)中(zhong)；2)lvbolianjieqiyizhidianlanfushedexiaoguobipingbidianlangengwending。pingbidianlandexiaoguozaihendachengdushangjuedingyudianlandeduanjie。youyudianlanpinfandechaizhuanghuojiaochangshijianhoudajiediandeyanghua，duanjiezukanghuizengjia
，zaochengpingbixiaonengxiajiang
；3)濾波連接器的使用

，可降低對電纜端接的要求
，降低生產成本，避免使用價格昂貴的高質量屏蔽電纜

，降低成本。

設計使用濾波連接器的試驗情況

分fen別bie使shi用yong普pu通tong連lian接jie器qi和he濾lv波bo連lian接jie器qi進jin行xing輻fu射she發fa射she研yan究jiu。從cong試shi驗yan結jie果guo可ke以yi看kan出chu，當dang使shi用yong屏ping蔽bi機ji箱xiang時shi，主zhu要yao的de輻fu射she源yuan是shi電dian纜lan。這zhe時shi使shi用yong濾lv波bo連lian接jie器qi可ke以yi使shi輻fu射she發fa射she強qiang度du降jiang低di10～30dB。

特(te)別(bie)在(zai)電(dian)磁(ci)環(huan)境(jing)複(fu)雜(za)的(de)今(jin)天(tian)
，電(dian)磁(ci)兼(jian)容(rong)技(ji)術(shu)顯(xian)得(de)越(yue)發(fa)重(zhong)要(yao)。在(zai)實(shi)際(ji)工(gong)程(cheng)應(ying)用(yong)中(zhong)使(shi)用(yong)濾(lv)波(bo)連(lian)接(jie)器(qi)對(dui)抗(kang)電(dian)磁(ci)幹(gan)擾(rao)
，可(ke)以(yi)起(qi)到(dao)良(liang)好(hao)的(de)效(xiao)果(guo)。設(she)計(ji)人(ren)員(yuan)隻(zhi)要(yao)在(zai)產(chan)品(pin)的(de)設(she)計(ji)初(chu)期(qi)考(kao)慮(lv)到(dao)產(chan)品(pin)的(de)電(dian)磁(ci)兼(jian)容(rong)性(xing)，在(zai)可(ke)能(neng)產(chan)生(sheng)幹(gan)擾(rao)的(de)地(di)方(fang)采(cai)取(qu)相(xiang)應(ying)的(de)抗(kang)幹(gan)擾(rao)措(cuo)施(shi)。這(zhe)樣(yang)，設(she)計(ji)的(de)係(xi)統(tong)就(jiu)能(neng)夠(gou)在(zai)複(fu)雜(za)的(de)電(dian)磁(ci)環(huan)境(jing)下(xia)正(zheng)常(chang)運(yun)行(xing)。