干(gan)線(xian)(xian)(xian)放(fang)大器是(shi)主干(gan)線(xian)(xian)(xian)纜(lan)傳(chuan)(chuan)輸(shu)鏈路上的(de)(de)雙(shuang)(shuang)向信(xin)(xin)(xin)(xin)號(hao)處理放(fang)大設備。當主干(gan)線(xian)(xian)(xian)纜(lan)傳(chuan)(chuan)輸(shu)距離長，或(huo)(huo)鏈路中(zhong)負載器件數量較多，雙(shuang)(shuang)向信(xin)(xin)(xin)(xin)號(hao)損(sun)耗過(guo)大，來自信(xin)(xin)(xin)(xin)號(hao)源（下行）或(huo)(huo)來自天(tian)(tian)線(xian)(xian)(xian)（上行）的(de)(de)信(xin)(xin)(xin)(xin)號(hao)強度偏低，相(xiang)關指標將不能滿足設計的(de)(de)技(ji)術要求，將直接影響到(dao)室(shi)內天(tian)(tian)線(xian)(xian)(xian)的(de)(de)端(duan)口發射功率和(he)基站接收(shou)機（中(zhong)繼(ji)臺)）的(de)(de)端(duan)口的(de)(de)接收(shou)功率，這就必(bi)須在主干(gan)線(xian)(xian)(xian)纜(lan)傳(chuan)(chuan)輸(shu)鏈路中(zhong)的(de)(de)適當位(wei)置增加(jia)干(gan)線(xian)(xian)(xian)放(fang)大器設備。

干線放大(da)器具有雙向信(xin)(xin)號(hao)(hao)放大(da)功能，上(shang)行(xing)/下行(xing)信(xin)(xin)號(hao)(hao)處理及放大(da)電路獨立(li)分開，上(shang)行(xing)/下行(xing)放大(da)功率可單獨調(diao)節，可根(gen)據實際要求進(jin)行(xing)現場測驗后(hou)對上(shang)行(xing)/下行(xing)信(xin)(xin)號(hao)(hao)增益(yi)進(jin)行(xing)分別設置，這樣極大(da)地方便(bian)了系統(tong)調(diao)試，從而更有效地保證了系統(tong)的安全穩(wen)定性(xing)和(he)建筑物內電磁環境滿足國(guo)家有關標(biao)準。