30.若超音波脈衝時間長度(pulseduration)為1μs ,且其責任因子(duty factor)為0.008 ,則脈衝重複週期 (pulse repetition period )為多少μs ?
(A)100
(B)125
(C)250
(D)800
答案:登入後查看
統計: A(16), B(1892), C(64), D(213), E(0) #2407849
統計: A(16), B(1892), C(64), D(213), E(0) #2407849