智能式电容耦合测试系统的设计与实现

【作者】 王煜华；

【导师】 蒋传纪；

【作者基本信息】 华东师范大学 ， 通信与信息系统， 2004， 硕士

【摘要】 近年来，通信技术和网络飞速发展，特别是网络发展迅猛，网络容量不断扩大，速度不断提高，使网络本身变得越来越复杂，电缆厂商不断推出更高速度的网络线缆，与之相应的网线测试得到了蓬勃发展，市场上出现了各式各样的网络线缆测试仪器。而作为传统话音通信线路主力的通信电缆，由于其技术成熟，更新较慢，相应的测试设备早已不是设备生产商关心的重点。尤其是在国内，对于此类进行专项测试、应用面较窄的测试设备不够重视，设计和开发的水平较低，设备陈旧，操作不便，这种局面有待改善。 传统的通信电缆参数测试采用交流电桥的方法，桥臂一边是标准电容器，另一边是待测电缆。通过选择合适的标准电容使电桥达到平衡，此时接入电桥的标准电容值就是待测电缆的电容值。此法原理简单明了，但是实际操作十分复杂，需要不停地调节标准电容器。 本文立足于提高国内通信电缆电容测试设备的技术性能，引入智能仪器的设计概念，对通信电缆电容测试仪进行了全新的设计。首先提出了新的测试方法——耦合电容直接测量法，利用不同的回路获得与待测电容值成正比的电流，测量这个电流并进行一定的数据处理就可以得到测试结果。其次将GB和ASTM两个标准的测试融为一体，提高了仪器的适用性。第三对仪器的外观和操作界面进行了全新的设计，探讨了仪器设计过程中的电磁兼容问题，提高仪器的抗干扰能力。最后利用模拟电缆测试板进行了预测，实验结果表示，该仪器完全体现出现代智能测试仪器的特点：测试精度高、操作简便、功能齐全。该仪器已通过高低温试验，目前正准备进行鉴定。更多还原

【Abstract】 With the rapid development of communication technology and network, the network capacitance is larger and larger. The cable manufactures continually produce new cables, so the net cable test instrument has developed too. More and more net cable testers appear in the market. But as the main force of the audio frequency communication line, the telephone cable tester is no longer the hotspot in test instrument industry, for the telephone cable has little change in recent years. In China, the situation is more serious. People don’t regard it as an important thing, so the research is in a low level.Classical telephone cable tester is based on AC bridge theory. Onside of the bridge is standard capacitance; on the other side is the test cable. By choosing the suitable standard capacitance, the bridge will balance. Then the value of the standard capacitance is just the value of the testing cable. The theory is sample, but the circuit will be not very practical because of too many adjustable components.This article aims at the telephone cable test’ technology performance in China, and introduces the design procedure of Smart Instruments. First, provide a new test method which can test the capacitance directly, without adjusting bridge balance. Second, put the GB and ASTM in one system. Third, design new structure and new interface for the system, and also discuss the EMC problem. At the end of the article, make a test by a simulate cable. The result of the experiment indicates that this testing system has high measurement precision, easy-operation and many useful functions. Generally speaking, the system in this article is completely accord with the need of intelligent measurement.更多还原