干(gan)線(xian)(xian)(xian)(xian)放大(da)器(qi)是主干(gan)線(xian)(xian)(xian)(xian)纜傳(chuan)(chuan)輸鏈路(lu)上的(de)(de)(de)雙向信(xin)號(hao)處理放大(da)設(she)(she)備。當(dang)主干(gan)線(xian)(xian)(xian)(xian)纜傳(chuan)(chuan)輸距離長(chang)，或(huo)鏈路(lu)中(zhong)負載器(qi)件數量較多，雙向信(xin)號(hao)損耗過大(da)，來自(zi)信(xin)號(hao)源（下行(xing)）或(huo)來自(zi)天線(xian)(xian)(xian)(xian)（上行(xing)）的(de)(de)(de)信(xin)號(hao)強(qiang)度偏低，相關指標將不(bu)能滿足設(she)(she)計的(de)(de)(de)技(ji)術要求，將直接(jie)(jie)影響到室內(nei)天線(xian)(xian)(xian)(xian)的(de)(de)(de)端(duan)口(kou)發射功率(lv)和基站接(jie)(jie)收機(ji)（中(zhong)繼臺)）的(de)(de)(de)端(duan)口(kou)的(de)(de)(de)接(jie)(jie)收功率(lv)，這就必(bi)須在主干(gan)線(xian)(xian)(xian)(xian)纜傳(chuan)(chuan)輸鏈路(lu)中(zhong)的(de)(de)(de)適當(dang)位置增(zeng)加干(gan)線(xian)(xian)(xian)(xian)放大(da)器(qi)設(she)(she)備。

干線放(fang)大器(qi)具有(you)雙向信(xin)號(hao)放(fang)大功(gong)能(neng)，上行(xing)(xing)/下行(xing)(xing)信(xin)號(hao)處理及放(fang)大電路獨立(li)分開，上行(xing)(xing)/下行(xing)(xing)放(fang)大功(gong)率(lv)可單獨調節，可根據實際(ji)要求進行(xing)(xing)現場測驗后對上行(xing)(xing)/下行(xing)(xing)信(xin)號(hao)增益(yi)進行(xing)(xing)分別(bie)設置，這(zhe)樣極(ji)大地(di)方便了(le)系(xi)(xi)統(tong)調試，從(cong)而更有(you)效地(di)保證了(le)系(xi)(xi)統(tong)的安全穩定(ding)性和(he)建(jian)筑物內電磁環境滿足(zu)國家有(you)關標準。