干(gan)線(xian)(xian)(xian)(xian)(xian)放大(da)器(qi)是主(zhu)干(gan)線(xian)(xian)(xian)(xian)(xian)纜傳輸(shu)鏈(lian)路(lu)上的(de)雙向信號處理放大(da)設備。當主(zhu)干(gan)線(xian)(xian)(xian)(xian)(xian)纜傳輸(shu)距離長(chang)，或鏈(lian)路(lu)中(zhong)負(fu)載器(qi)件數量較(jiao)多，雙向信號損耗(hao)過大(da)，來自(zi)信號源（下行(xing)）或來自(zi)天(tian)線(xian)(xian)(xian)(xian)(xian)（上行(xing)）的(de)信號強(qiang)度偏低，相關指標將不能滿足設計的(de)技(ji)術(shu)要(yao)求，將直接影(ying)響(xiang)到室內(nei)天(tian)線(xian)(xian)(xian)(xian)(xian)的(de)端口發射功(gong)率和基站接收(shou)機（中(zhong)繼臺(tai))）的(de)端口的(de)接收(shou)功(gong)率，這(zhe)就必須在主(zhu)干(gan)線(xian)(xian)(xian)(xian)(xian)纜傳輸(shu)鏈(lian)路(lu)中(zhong)的(de)適當位(wei)置增(zeng)加(jia)干(gan)線(xian)(xian)(xian)(xian)(xian)放大(da)器(qi)設備。

干線放(fang)大器具有(you)雙向信(xin)號(hao)放(fang)大功能，上行(xing)(xing)(xing)(xing)/下行(xing)(xing)(xing)(xing)信(xin)號(hao)處理及放(fang)大電路獨(du)立分開，上行(xing)(xing)(xing)(xing)/下行(xing)(xing)(xing)(xing)放(fang)大功率可單獨(du)調(diao)節，可根據實際(ji)要求進行(xing)(xing)(xing)(xing)現場測(ce)驗后(hou)對上行(xing)(xing)(xing)(xing)/下行(xing)(xing)(xing)(xing)信(xin)號(hao)增益(yi)進行(xing)(xing)(xing)(xing)分別設置，這樣極大地方便了系(xi)統調(diao)試，從而更有(you)效地保證了系(xi)統的安全(quan)穩定性(xing)和建筑(zhu)物內電磁環境滿足國家有(you)關標準。