A.Ⅰ B.Ⅱ C.Ⅲ D.Ⅳ
A.5% B.10% C.20% D.15%
A.0-KHz B.0-2KHz C.0-5KHz D.0-10KHz
A.50 B.55 C.60 D.65
A.45°;1/2 B.90°;1/3 C.45°;1/3 D.90°;1/2