干(gan)線(xian)(xian)(xian)(xian)(xian)(xian)放大(da)器(qi)是主干(gan)線(xian)(xian)(xian)(xian)(xian)(xian)纜傳(chuan)(chuan)輸鏈(lian)(lian)路上的(de)雙(shuang)(shuang)向信號(hao)(hao)(hao)處理放大(da)設備。當(dang)主干(gan)線(xian)(xian)(xian)(xian)(xian)(xian)纜傳(chuan)(chuan)輸距離(li)長，或(huo)鏈(lian)(lian)路中負載器(qi)件數量較多(duo)，雙(shuang)(shuang)向信號(hao)(hao)(hao)損(sun)耗過大(da)，來自信號(hao)(hao)(hao)源（下行）或(huo)來自天(tian)線(xian)(xian)(xian)(xian)(xian)(xian)（上行）的(de)信號(hao)(hao)(hao)強度(du)偏低，相(xiang)關(guan)指標(biao)將不(bu)能滿足(zu)設計(ji)的(de)技(ji)術要(yao)求，將直接(jie)影響到室(shi)內天(tian)線(xian)(xian)(xian)(xian)(xian)(xian)的(de)端(duan)口發射功率(lv)和基(ji)站(zhan)接(jie)收(shou)機（中繼臺)）的(de)端(duan)口的(de)接(jie)收(shou)功率(lv)，這就(jiu)必須在(zai)主干(gan)線(xian)(xian)(xian)(xian)(xian)(xian)纜傳(chuan)(chuan)輸鏈(lian)(lian)路中的(de)適當(dang)位(wei)置增(zeng)加干(gan)線(xian)(xian)(xian)(xian)(xian)(xian)放大(da)器(qi)設備。

干線放(fang)(fang)大(da)(da)器(qi)具(ju)有雙向信(xin)號(hao)放(fang)(fang)大(da)(da)功(gong)能，上(shang)行(xing)/下行(xing)信(xin)號(hao)處理(li)及放(fang)(fang)大(da)(da)電路獨立分(fen)開(kai)，上(shang)行(xing)/下行(xing)放(fang)(fang)大(da)(da)功(gong)率(lv)可單獨調節，可根(gen)據實(shi)際要求進行(xing)現場測(ce)驗后對上(shang)行(xing)/下行(xing)信(xin)號(hao)增(zeng)益(yi)進行(xing)分(fen)別設置，這樣極大(da)(da)地方便(bian)了系統(tong)(tong)調試，從(cong)而(er)更有效地保證了系統(tong)(tong)的(de)安全穩定(ding)性和(he)建筑物內電磁(ci)環境滿足國(guo)家(jia)有關標準。