用电压的变化表示0和1.规定在每个码元中间发生跳变.高→ 低的跳变表示0,低→ 高的跳变表示为1,也就是用01表示0,用10表示1.每个码元中间都要发生跳变,接收端可将此变化提取出来作为同步信号,使接收端的时钟与发送设备的时钟保持一致.-With the voltage changes that have 0 and 1. Provides that each code element transitions occurring in the middle. High to low transition that 0, low to high transition is expressed as 1, that is, 01, said with 0, with 10 indicating that a . yuan middle of each code transition should occur, the receiver can be extracted from this change as a sync signal to the receiver' s clock and send the device' s clock consistency.