传输线无畸变传输条件的教学方法

The Teaching Method of Distortionless Transmission Condition of Transmission Lines

传输线广泛出现在电能和信号传输中,它在传输非正弦周期信号时会出现稳态波形畸变。为了避免畸变,必须依据无畸变传输条件合理选择传输线参数。本文将"信号与系统"、"电磁场"和"电路理论"等课程中无畸变传输概念贯通,利用傅里叶级数和传递函数,导出线性时不变网络无畸变稳态传输的一般性条件;由此获得传输线无畸变稳态传输条件;并分析媒质无色散传输条件和传输线无畸变传输条件的差异。

Uniform transmission lines are used in energy and signal transmission widely. There is distortion when nonsinusoid signal is transferred by a transmission line. To avoid the distortion, it is necessary to choose the param- eters of the transmission line reasonably according to the distortionless transmission condition. Combining the con- cepts of distortionless transmission in courses of Signals and Systems and Circuit Theory and Electromagnetics, using Fourier series and transfer function, the distortionless transmission condition of a linear time-invariant network is derived obviously and by that condition the distortionless transmission condition of a transmission line is obtained. The difference between the distortionless transmission conditions of dispersionless medium and distortionless trans- mission line is analysed.