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| 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。 |
| 关键词: 接口 电气特性 USB接口 计算机 |
| DOI： |
| 分类号:TP334.7 |
| 基金项目: |
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| USB Electrical Specification |
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CHEN Qi-mei 1 2 ZHOU Yu-jun 1 DING Chuan-suo 2 CHEN Suo-zhu 3
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| Abstract: |
| 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. |
| Key words: electrical specification of interface,port power-supply mode,NRZI data encoding,bit synchronization, |
