A. 总时差 B. 共用时差 C. 单时差 D. 线路时差
A. 同频单工 B. 异频单工 C. 异频双工 D. 半双工 E. 同频双工
A. 停气 B. 降压 C. 带气 D. 带火
A. +5V B. –24V C. –48V D. –75V E. –5V
A. 1,0.02 B. 0.5,0.01 C. 0.5,0.02 D. 1,0.01