Adsl Tester Developed

The ADSL technology, namely Asymmetric Digital Subscriber Line, is one kind of asymmetrical transmission technologies which realizes the high speed data transmission in the copper cable through the different modulation methods. ADSL uses the high frequency band which has not been used in the common telephone line and the advanced modulating technique to provide broadband access. Because the average users use the net mainly to download data, ADSL proposes the way of making the rate of downstream bigger than the upstream according to the realistic situation. As a result Asymmetric Digital Subscriber Line came out. ADSL transmits in the telephone line, so each user use the bandwidth separately (average 2M). What's more, the security of this way is much higher than sharing bandwidth access.ADSL becomes one of the access technologies which develop most rapidly at present by many advantages. How to satisfy the users who request uninterruptedly and stable network has become the most important topic of the telecommunication business. In order to search and solve the ADSL line fault when the user accesses the net, we introduce one kind ADSL Fault Detect i ng instrument in this thesis. The instrument is mainly composed by the W78LE516 chip, [the special-purpose test set of piece], the Liquid Crystal Display, the keyboard and so on. The single-chip functions as the Human Machine Interface and procedure controller; the set of piece works mainly with the test function. At the same time according to the characteristic of the line, the instrument adds the electrical characteristic of DMM test to judge the line.In the first chapter of the thesis we expatiate on the background and the significance of the topic, we also summarize the present situation of ADSL and analyze the line condition which is suitable to perform the ADSL operation. And these conditions are the line conditions which are examined before the ADSL operation works. We need to adjust the line if some do not conform to the requirement. In the process of the users using ADSL to access the net, some problems may appear, including break from linking to the net, the line falls, the slow speed and so on. These problems involve in the line maintenance. How to find the factors which influence the users to access the net rapidly is the first thing which the line maintenance personnel...