Experiment Research On Uniform Transmission Line

With the need of development of technique for modern electron, communication and electric power industry, people pay more and more attention to transmission lines. Because of the short delay on transmission lines, it is difficult to study on transmission characteristics of transmission lines by test. But with the produce of high-speed integrated devices, it is possible to study the transmission lines by test means. People will observe some phenomena by test means that cannot be observed by simulation. The study even will give some references to research on EHV transmission line fault locator.This paper brings forward designs and schemes for study on transmission lines, based on electron, computer and FPGA techniques. Firstly, according to the transmission characteristics of the traveling wave on transmission lines, use a uniformity transmission lines model based on twisted-pair and coaxial-cable, apply the merit of FPGA such as high speed, agility, etc. a test device on measuring delay of reflected wave is introduced, which is composed of AD9054 and EPLC6 and their corresponding assistant circuits. This device is based on transmission characteristics of traveling-wave, and the uniform transmission line is the cable of telephone.Secondly, in order to observe transient traveling wave on transmission lines, a high-speed data acquisition system based on FPGA is provided. The primary function of this system is high-speed addressing, fast storage and control technology between A/D converter and fast storage, so real time sampling of high-speed transient traveling wave was realized in this system.At last, the paper discusses the important practicality of the study and gives some advice on updating the system in future.It is made clear by the task that studying the characteristics of transmission lines by test means is feasible. The schemes of data acquisition and data processing will give some reference to other control system. With the rapid development of the technology of electron and computer, the theory about transmission line will be more and more prefect under the study of scholars in the world.