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)敏(min)感(gan)設(she)備(bei)。電(dian)磁(ci)兼(jian)容(rong)設(she)計(ji)從(cong)這(zhe)三(san)個(ge)方(fang)麵(mian)做(zuo)工(gong)作(zuo)。其(qi)中(zhong)濾(lv)波(bo)連(lian)接(jie)器(qi)是(shi)解(jie)決(jue)耦(ou)合(he)路(lu)徑(jing)的(de)絕(jue)佳(jia)方(fang)法(fa)之(zhi)一(yi)。濾(lv)波(bo)連(lian)接(jie)是(shi)一(yi)種(zhong)具(ju)備(bei)濾(lv)波(bo)功(gong)能(neng)的(de)連(lian)接(jie)器(qi)。通(tong)常(chang)工(gong)程(cheng)上(shang)使(shi)用(yong)的(de)信(xin)號(hao)電(dian)纜(lan)是(shi)屏(ping)蔽(bi)電(dian)纜(lan)，但(dan)仍(reng)不(bu)能(neng)滿(man)足(zu)電(dian)磁(ci)兼(jian)容(rong)標(biao)準(zhun)，對(dui)於(yu)高(gao)頻(pin)幹(gan)擾(rao)的(de)屏(ping)蔽(bi)

，主(zhu)要(yao)原(yuan)因(yin)是(shi)屏(ping)蔽(bi)電(dian)纜(lan)是(shi)金(jin)屬(shu)編(bian)製(zhi)網(wang)，上(shang)麵(mian)的(de)孔(kong)洞(dong)會(hui)在(zai)高(gao)頻(pin)時(shi)產(chan)生(sheng)泄(xie)露(lu)
，另(ling)外(wai)一(yi)個(ge)原(yuan)因(yin)是(shi)屏(ping)蔽(bi)電(dian)纜(lan)的(de)高(gao)屏(ping)蔽(bi)效(xiao)能(neng)取(qu)決(jue)於(yu)電(dian)纜(lan)屏(ping)蔽(bi)層(ceng)的(de)端(duan)接(jie)情(qing)況(kuang)
，隻(zhi)有(you)當(dang)電(dian)纜(lan)屏(ping)蔽(bi)層(ceng)的(de)端(duan)接(jie)為(wei)360度(du)低(di)阻(zu)抗(kang)搭(da)接(jie)時(shi)，才(cai)會(hui)有(you)較(jiao)理(li)想(xiang)的(de)高(gao)屏(ping)蔽(bi)效(xiao)果(guo)，很(hen)多(duo)場(chang)合(he)下(xia)都(dou)無(wu)法(fa)保(bao)證(zheng)。濾(lv)波(bo)連(lian)接(jie)器(qi)能(neng)夠(gou)有(you)效(xiao)的(de)濾(lv)除(chu)不(bu)必(bi)要(yao)的(de)高(gao)頻(pin)成(cheng)分(fen)，彌(mi)補(bu)了(le)屏(ping)蔽(bi)電(dian)纜(lan)對(dui)於(yu)高(gao)頻(pin)幹(gan)擾(rao)屏(ping)蔽(bi)的(de)不(bu)足(zu)"。

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％dedianciganraowentishiyouyudianlanzaochengde。dianlanshigaoxiaodediancibojieshoutianxianhefushetianxian

，dianlanchanshengdefusheyouqiyanzhong。dianlanduankouchuyougongmodianyacunzai，dianlanzaizhegegongmodianyadequdongxia，rutongyigendanjitianxian。tachanshengdedianchangfusheruxiashisuoshi：

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)lvbolianjieqinengjiangdianlanzhongdeganraodianliulvchudiao
，chedixiaochudianlandefusheyinsu。pingbidianlanjinjinshifangzhiganraotongguodianlanfushe，shijizhexieganraodianliuhaizaidianlanzhong
；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。