本帖最后由 shikkoku 于 2022-6-8 17:26 编辑
现在不是有不少“hifi” usb线是用了类似耳机升级线那种线基嘛,但其实这USB数据线和同轴线一样有阻抗标准的。同轴线标准是75欧姆。
摘录自《Universal Serial Bus Specification Revision 2.0》
7.1.1.3 High-speed (480 Mb/s) Driver Characteristics
A high-speed USB connection is made through a shielded, twisted pair cable with a differential characteristic
impedance (Z0) of 90 Ω ±15%, a common mode impedance (ZCM) of 30 Ω ±30%, and a maximum one-way
delay of 26 ns (TFSCBL). The D+ and D- circuit board traces which run between a transceiver and its associated
connector should also have a nominal differential impedance of 90 Ω, and together they may add an additional
4 ns of delay between the transceivers.
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