在(zai)通(tong)信(xin)設備、計算機、控(kong)制和(he)儀表(biao)系(xi)統(tong)、無(wu)線電(dian)(dian)系(xi)統(tong)和(he)電(dian)(dian)力電(dian)(dian)子裝置構成的(de)(de)(de)電(dian)(dian)子系(xi)統(tong)，會經常受到雷(lei)電(dian)(dian)感應能量的(de)(de)(de)損害(hai)。雷(lei)電(dian)(dian)過(guo)電(dian)(dian)壓的(de)(de)(de)破壞除了從電(dian)(dian)源系(xi)統(tong)進(jin)入外，通(tong)過(guo)各種信(xin)號接口與(yu)線路的(de)(de)(de)侵(qin)入也(ye)十分普遍(bian)。信(xin)號浪涌保護(hu)(hu)器是用于保護(hu)(hu)信(xin)息(xi)系(xi)統(tong)（如數據(ju)回路、通(tong)信(xin)、控(kong)制電(dian)(dian)路）的(de)(de)(de)浪涌保護(hu)(hu)器。那(nei)么，信(xin)號浪涌保護(hu)(hu)器該如何進(jin)行(xing)選(xuan)擇呢？今(jin)天，鈞(jun)和(he)電(dian)(dian)子為您詳細講解。

與(yu)電源浪涌(yong)保護器不同(tong)，由于信號浪涌(yong)保護器在使用過程(cheng)中(zhong)，對所在線(xian)路的(de)數據傳輸(shu)影響巨大(da)，因此，除了要滿足電涌(yong)脈沖防(fang)護的(de)功(gong)能之外(wai)，自身(shen)還需要具備對線(xian)路的(de)匹配功(gong)能、減少損耗、最大(da)限度(du)不影響原線(xian)路的(de)傳輸(shu)特(te)性，因此對以下幾個參數要求嚴格：

1.插入損(sun)耗：電(dian)(dian)氣(qi)系(xi)統(tong)(tong)中，在(zai)(zai)給定(ding)頻率(lv)下，連接(jie)(jie)到給定(ding)電(dian)(dian)源(yuan)系(xi)統(tong)(tong)的(de)(de)(de)(de)浪(lang)涌(yong)(yong)保(bao)護(hu)(hu)器的(de)(de)(de)(de)插入(ru)損耗(hao)(hao)定(ding)義為(wei)，電(dian)(dian)源(yuan)線上緊(jin)靠浪(lang)涌(yong)(yong)保(bao)護(hu)(hu)器接(jie)(jie)入(ru)點(dian)之(zhi)后(hou)，在(zai)(zai)被試浪(lang)涌(yong)(yong)保(bao)護(hu)(hu)器接(jie)(jie)入(ru)前(qian)后(hou)的(de)(de)(de)(de)電(dian)(dian)壓比。在(zai)(zai)電(dian)(dian)子(zi)系(xi)統(tong)(tong)中，由(you)于在(zai)(zai)傳(chuan)輸系(xi)統(tong)(tong)中插入(ru)一個浪(lang)涌(yong)(yong)保(bao)護(hu)(hu)器所引起的(de)(de)(de)(de)損耗(hao)(hao)，它是在(zai)(zai)浪(lang)涌(yong)(yong)保(bao)護(hu)(hu)器插入(ru)前(qian)傳(chuan)遞到后(hou)面系(xi)統(tong)(tong)部分的(de)(de)(de)(de)功率(lv)與浪(lang)涌(yong)(yong)保(bao)護(hu)(hu)器插入(ru)后(hou)傳(chuan)遞到同一部分的(de)(de)(de)(de)功率(lv)之(zhi)比。插入(ru)損耗(hao)(hao)通(tong)常(chang)用分貝（dB）表示(shi)，通(tong)常(chang)這(zhe)個值不超過0.2dB。

2.回波損耗：反射系數倒(dao)數的模，一般用分貝表示；

3.近端(duan)串擾(rao)：串擾(rao)在(zai)被(bei)干(gan)(gan)(gan)擾(rao)的(de)通(tong)道(dao)中(zhong)傳輸，其方向(xiang)與(yu)產生干(gan)(gan)(gan)擾(rao)的(de)通(tong)道(dao)中(zhong)電(dian)流傳輸的(de)方向(xiang)相反。在(zai)被(bei)干(gan)(gan)(gan)擾(rao)的(de)通(tong)道(dao)中(zhong)產生的(de)近端串擾(rao)，其端口(kou)通(tong)常靠近產生干(gan)(gan)(gan)擾(rao)的(de)通(tong)道(dao)的(de)功(gong)能端，或與(yu)之重合。

4.分布電容：信(xin)號(hao)浪涌(yong)保護器不管其內部元(yuan)件是(shi)(shi)使用氣體放電(dian)(dian)(dian)(dian)(dian)管還(huan)是(shi)(shi)半導體放電(dian)(dian)(dian)(dian)(dian)管或(huo)壓敏電(dian)(dian)(dian)(dian)(dian)阻，在(zai)信(xin)號(hao)線路與地線之間(jian)都或(huo)多或(huo)少存在(zai)著分(fen)布(bu)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)，高頻信(xin)號(hao)會通過這個(ge)旁路電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)旁路到地，造成高頻信(xin)號(hao)的(de)損失。在(zai)各種元(yuan)件中(zhong)，氣體放電(dian)(dian)(dian)(dian)(dian)管的(de)分(fen)布(bu)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)最(zui)小，半導體放電(dian)(dian)(dian)(dian)(dian)管的(de)分(fen)布(bu)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)次之，壓敏電(dian)(dian)(dian)(dian)(dian)阻的(de)分(fen)布(bu)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)最(zui)大；

5.帶(dai)寬(kuan)：信(xin)號線的(de)(de)(de)種類很多，傳(chuan)(chuan)輸(shu)(shu)速(su)率(lv)各(ge)不相同(tong)。電話撥(bo)號的(de)(de)(de)傳(chuan)(chuan)輸(shu)(shu)速(su)率(lv)為(wei)64kbit/s，而ADSL、DDN為(wei)2kbit/s，網(wang)絡雙(shuang)絞線有(you)10Mbit/s、100Mbit/s、1000Mbit/s等。同(tong)軸電纜有(you)2Mbit/s、10Mbit/s、40Mbit/s等。不同(tong)的(de)(de)(de)傳(chuan)(chuan)輸(shu)(shu)速(su)率(lv)對信(xin)號帶(dai)(dai)(dai)(dai)寬(kuan)的(de)(de)(de)要(yao)(yao)求(qiu)不同(tong)，速(su)率(lv)越(yue)高，要(yao)(yao)求(qiu)的(de)(de)(de)帶(dai)(dai)(dai)(dai)寬(kuan)越(yue)寬(kuan)。另(ling)外(wai)，信(xin)號載波頻(pin)(pin)(pin)率(lv)對電路的(de)(de)(de)帶(dai)(dai)(dai)(dai)寬(kuan)也有(you)不同(tong)的(de)(de)(de)要(yao)(yao)求(qiu)。通(tong)常，低(di)(di)頻(pin)(pin)(pin)信(xin)號要(yao)(yao)求(qiu)電路的(de)(de)(de)幅頻(pin)(pin)(pin)特性是低(di)(di)通(tong)，中頻(pin)(pin)(pin)信(xin)號一(yi)般是帶(dai)(dai)(dai)(dai)通(tong)，而高頻(pin)(pin)(pin)信(xin)號則(ze)要(yao)(yao)求(qiu)高通(tong)或帶(dai)(dai)(dai)(dai)通(tong)。浪涌保護器的(de)(de)(de)帶(dai)(dai)(dai)(dai)寬(kuan)既要(yao)(yao)滿(man)足傳(chuan)(chuan)輸(shu)(shu)速(su)率(lv)對信(xin)號帶(dai)(dai)(dai)(dai)寬(kuan)的(de)(de)(de)要(yao)(yao)求(qiu)，又要(yao)(yao)滿(man)足載波頻(pin)(pin)(pin)率(lv)對電路帶(dai)(dai)(dai)(dai)寬(kuan)的(de)(de)(de)要(yao)(yao)求(qiu)。如果浪涌保護器的(de)(de)(de)帶(dai)(dai)(dai)(dai)寬(kuan)不足，會(hui)使得部分(fen)信(xin)號無(wu)法傳(chuan)(chuan)輸(shu)(shu)。

6.阻抗匹配：阻(zu)抗(kang)匹配(pei)也(ye)是(shi)影響信號傳輸的(de)(de)(de)一個因素。如果浪(lang)涌保(bao)護器(qi)(qi)的(de)(de)(de)阻(zu)抗(kang)和線(xian)路(lu)(lu)不匹配(pei)，就會在線(xian)路(lu)(lu)上產生反射波(bo)，形成駐波(bo)，造成信號功率的(de)(de)(de)衰減(jian)。這(zhe)一點對同(tong)軸(zhou)(zhou)電(dian)纜尤(you)(you)為重要，同(tong)軸(zhou)(zhou)電(dian)纜抗(kang)干擾(rao)能力(li)很弱，尤(you)(you)其(qi)(qi)是(shi)LEMP對其(qi)(qi)影響很大，需要通過安裝(zhuang)(zhuang)BNC接口的(de)(de)(de)浪(lang)涌保(bao)護器(qi)(qi)來防止電(dian)壓的(de)(de)(de)入侵，安裝(zhuang)(zhuang)時就需要做(zuo)到線(xian)路(lu)(lu)的(de)(de)(de)阻(zu)抗(kang)匹配(pei)，根據情況其(qi)(qi)匹配(pei)阻(zu)抗(kang)分為50Ω和70Ω兩(liang)種情況。

7.工作電壓(ya)：傳(chuan)輸信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)的(de)種類很多(duo)，有(you)(you)模擬信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)、數字信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)、控制信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)、數據信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)、音頻信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)、視頻信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)、低(di)頻信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)、高頻信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)等。信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)電(dian)(dian)(dian)壓(ya)也(ye)各不(bu)相(xiang)同，有(you)(you)直流(liu)、交(jiao)流(liu)，電(dian)(dian)(dian)壓(ya)有(you)(you)5V、12V、24V、48V、100V等。信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)電(dian)(dian)(dian)壓(ya)不(bu)同，對浪(lang)(lang)涌保(bao)護(hu)(hu)器(qi)(qi)的(de)標稱導(dao)通(tong)電(dian)(dian)(dian)壓(ya)有(you)(you)不(bu)同的(de)要求。如果浪(lang)(lang)涌保(bao)護(hu)(hu)器(qi)(qi)的(de)標稱導(dao)通(tong)電(dian)(dian)(dian)壓(ya)過低(di)，會使浪(lang)(lang)涌保(bao)護(hu)(hu)器(qi)(qi)頻繁導(dao)通(tong)，影響(xiang)信(xin)(xin)(xin)(xin)(xin)號(hao)(hao)的(de)通(tong)過，也(ye)使浪(lang)(lang)涌保(bao)護(hu)(hu)器(qi)(qi)容易損(sun)壞；而(er)標稱導(dao)通(tong)電(dian)(dian)(dian)壓(ya)過高，又(you)可能會使得雷(lei)電(dian)(dian)(dian)過電(dian)(dian)(dian)壓(ya)進入保(bao)護(hu)(hu)設備，起不(bu)到應有(you)(you)的(de)防雷(lei)作用。

信(xin)號(hao)(hao)浪涌保護(hu)器(qi)要(yao)(yao)根據信(xin)號(hao)(hao)的特性和信(xin)號(hao)(hao)接口的類(lei)型進行設計，需要(yao)(yao)符合(he)GB18802.21《電信(xin)與信(xin)號(hao)(hao)網絡浪涌保護(hu)器(qi)的性能與試(shi)驗方法》的技術要(yao)(yao)求。