NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–CCTV Tester
Reflection and Transmission of Traveling Waves When two cables with different wave impedances are connected, there will be an impedance mismatch at the connection point. When there is a disconnection or low-resistance fault in the cable, the equivalent impedance of the fault point is not equal to the cable wave impedance, and impedance mismatch will also occur. When two cables with different wave impedances are connected, there will be an impedance mismatch at the connection point.
When there is a disconnection or low-resistance fault in the cable, the equivalent impedance of the fault point is not equal to the cable wave impedance, and impedance mismatch will also occur. When the traveling wave moves to the point of impedance mismatch, all or part of the reflection will occur, and the phenomenon of traveling wave echo occurs. In a low resistance fault (when the resistance at the fault point is not zero), there will also be traveling wave transmission, that is, a part of the traveling wave will continue to move forward across the fault point.
The phenomenon of reflection and transmission of traveling waves when cables have low resistance faults. Ui is the incident wave, Uf is the returned reflected wave, and Ut is the transmitted wave that crosses the fault point. Note that the incident wave and the transmitted wave of the traveling wave reflect a causal relationship, that is, the incident wave causes the reflected wave and the transmitted wave to appear at the impedance mismatch point.
The forward and reverse traveling waves are for the direction of motion of the voltage and current waves. An incident wave can be a forward traveling wave or a reverse traveling wave. If the moving direction of the incident wave is consistent with the specified direction, it is a forward traveling wave, and the corresponding reflected wave and transmitted wave should be opposite and the same as the moving direction of the incident wave, which are called reverse traveling waves and forward traveling waves.
Conversely, the incident wave is a reverse traveling wave, and the corresponding reflected and transmitted waves should be forward and reverse traveling waves, respectively. 1111MicrosoftInternetExplorer402DocumentNotSpecified7.8 ptNormal0.
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