干(gan)線(xian)(xian)放(fang)大器是主干(gan)線(xian)(xian)纜(lan)傳(chuan)輸鏈路上的(de)(de)雙向信(xin)(xin)號處理放(fang)大設(she)備。當主干(gan)線(xian)(xian)纜(lan)傳(chuan)輸距離長，或鏈路中(zhong)負載器件(jian)數(shu)量較多，雙向信(xin)(xin)號損耗過大，來(lai)自信(xin)(xin)號源（下行）或來(lai)自天線(xian)(xian)（上行）的(de)(de)信(xin)(xin)號強度(du)偏低，相關指標將(jiang)不能(neng)滿足(zu)設(she)計的(de)(de)技術要求，將(jiang)直接(jie)影響到室內天線(xian)(xian)的(de)(de)端(duan)口發射(she)功率和基(ji)站接(jie)收機(ji)（中(zhong)繼(ji)臺)）的(de)(de)端(duan)口的(de)(de)接(jie)收功率，這(zhe)就必須在(zai)主干(gan)線(xian)(xian)纜(lan)傳(chuan)輸鏈路中(zhong)的(de)(de)適當位(wei)置增加干(gan)線(xian)(xian)放(fang)大器設(she)備。

干(gan)線放大(da)(da)(da)器具有(you)雙向信(xin)號放大(da)(da)(da)功(gong)能，上(shang)(shang)行(xing)(xing)(xing)(xing)/下(xia)行(xing)(xing)(xing)(xing)信(xin)號處理及放大(da)(da)(da)電(dian)路獨(du)立分開(kai)，上(shang)(shang)行(xing)(xing)(xing)(xing)/下(xia)行(xing)(xing)(xing)(xing)放大(da)(da)(da)功(gong)率(lv)可(ke)單獨(du)調節，可(ke)根據實際要求進(jin)行(xing)(xing)(xing)(xing)現場測驗(yan)后(hou)對上(shang)(shang)行(xing)(xing)(xing)(xing)/下(xia)行(xing)(xing)(xing)(xing)信(xin)號增(zeng)益進(jin)行(xing)(xing)(xing)(xing)分別設置，這(zhe)樣極大(da)(da)(da)地方便了系統調試，從而更有(you)效地保證(zheng)了系統的安全(quan)穩定(ding)性和建筑物(wu)內電(dian)磁環境滿足(zu)國家有(you)關標(biao)準(zhun)。