干(gan)(gan)線(xian)(xian)放(fang)大器(qi)(qi)是主干(gan)(gan)線(xian)(xian)纜傳(chuan)輸(shu)(shu)鏈(lian)路(lu)上的雙向信(xin)(xin)號處理放(fang)大設(she)備(bei)。當(dang)主干(gan)(gan)線(xian)(xian)纜傳(chuan)輸(shu)(shu)距離(li)長(chang)，或鏈(lian)路(lu)中負載器(qi)(qi)件數(shu)量較多，雙向信(xin)(xin)號損耗過大，來自信(xin)(xin)號源（下行）或來自天線(xian)(xian)（上行）的信(xin)(xin)號強度偏低，相(xiang)關指標將(jiang)不能滿足設(she)計的技術要求，將(jiang)直接(jie)(jie)影響到(dao)室內天線(xian)(xian)的端(duan)口(kou)(kou)發射功(gong)率和基(ji)站接(jie)(jie)收機（中繼臺)）的端(duan)口(kou)(kou)的接(jie)(jie)收功(gong)率，這就必須在主干(gan)(gan)線(xian)(xian)纜傳(chuan)輸(shu)(shu)鏈(lian)路(lu)中的適當(dang)位(wei)置增加干(gan)(gan)線(xian)(xian)放(fang)大器(qi)(qi)設(she)備(bei)。

干(gan)線(xian)放大器(qi)具有雙向信號(hao)放大功(gong)能，上(shang)行(xing)(xing)(xing)(xing)(xing)/下行(xing)(xing)(xing)(xing)(xing)信號(hao)處理及放大電路獨立(li)分開，上(shang)行(xing)(xing)(xing)(xing)(xing)/下行(xing)(xing)(xing)(xing)(xing)放大功(gong)率可單獨調(diao)節，可根據實際(ji)要求進(jin)行(xing)(xing)(xing)(xing)(xing)現場測驗(yan)后對上(shang)行(xing)(xing)(xing)(xing)(xing)/下行(xing)(xing)(xing)(xing)(xing)信號(hao)增益進(jin)行(xing)(xing)(xing)(xing)(xing)分別設(she)置，這樣極大地方便了(le)系統調(diao)試，從而(er)更有效地保(bao)證了(le)系統的安全穩定性和(he)建筑(zhu)物(wu)內(nei)電磁環(huan)境(jing)滿足國家有關標準。