下列說法屬于聯(lián)合檢測作用的是：（  ）
Which of the followings belong to the joint detection effect? ( )
A.降低干擾
Reduce interferences
B.提高系統(tǒng)容量
Improve the system capacity
C.降低功控要求
Reduce the power control requirements
D.削弱遠近效應
Weaken the near-far effect