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在美国,功率传输用标准同轴线阻抗是50欧姆,而共用天线电视和一些别的小信号场合用的标准阻抗是75欧姆。人们常常提出这个问题,就是为什么选择这些阻抗值。在同轴传输线中,电磁波是通过二个同轴的圆柱体所包围的电介质传播的,由于在甚高频下电流穿透很小,(在54兆赫时,铜导体
In the United States, the standard coaxial impedance for power transmission is 50 ohms, while the standard impedance for common antenna television and some other small signals is 75 ohms. People often ask this question, which is why you choose these values. In coaxial transmission lines, electromagnetic waves are propagated through the dielectric surrounded by two coaxial cylinders, due to the small current penetration at very high frequencies (at 54 MHz, the copper conductor