说明：  PCIE 这样的高频环境中，传送线在信号线上驱动电压变化时会出现阻抗，信号线的宽度和到接地的距离都会影响其阻抗，所以在设计 PCB 时需要参考 PCIE总线规范，特别要注意考虑信号阻抗匹配。
(In the high frequency environment such as PCIe, when the driving voltage of the transmission line changes on the signal line, the impedance will be affected by the width of the signal line and the distance to the ground. Therefore, when designing PCB, it is necessary to refer to the PCIe bus specification, especially to consider the signal impedance matching.)