（）傳遞需要調(diào)制編碼。A.數(shù)字數(shù)據(jù)在數(shù)字信道上B.數(shù)字數(shù)據(jù)在模擬信道上 C.模擬數(shù)據(jù)在數(shù)字信道上 D.模擬數(shù)據(jù)在模擬信道上
