A.星型結(jié)構(gòu) B.樹形結(jié)構(gòu) C.環(huán)形結(jié)構(gòu)
A.1/10 B.1/100 C.1/1000 D.1/10000
A.數(shù)字調(diào)幅 B.數(shù)字調(diào)相 C.數(shù)字調(diào)頻