摘要
USB的电气特性反映了端口驱动电路、传输电平、编码结构、位同步处理及供电方式。USB串行数据采用了NRZI编码 ,在USB数据线上传输。对数据进行差分编码有助于噪声抵消和确保数据的正确性。给出了驱动信号的波形和阈值。为了避免长“1”码影响同步信号的提取 ,USB采用了“0”翻转插入方式。USB端口对于相连的设备均可提供 2种供电方式 ,即总线供电方式和自供电方式。
The USB electrical specifications describe the port driver circuit,electrical level of data transmission,code structure, bit synchronization and power distribution.USB employs NRZI data encoding to transmit USB serial data.USB uses differential signal to minimize noise and assure data correctness. The waveform and threshold values of driving signal are given.USB inserts signal '0' to avoid missing synch for long signal series of '1'.All USB ports support two power-supply modes for the connected equipment:bus-powered and self-powered.
出处
《电力自动化设备》
EI
CSCD
北大核心
2001年第9期68-71,共4页
Electric Power Automation Equipment
关键词
接口
电气特性
USB接口
计算机
electrical specification of interface
port power-supply mode
NRZI data encoding
bit synchronization
