A.直流電壓 B.交流電壓 C.直流電流 D.交流電流
A.1s,4次,5s,30% B.0.5s,3次,5s,30% C.0.5s,4次,10s,20% D.1s,3次,10s,20%
A.余弦處理 B.反余弦處理 C.正弦處理 D.反正弦處理