الفهرس | Only 14 pages are availabe for public view |
Abstract Inthis thesis different methods for testing the transmission impairments on analogue telephone channels (lines) are discussed. M.easurements may be performed either in the planning stage, during _operation or in the presence of faults. The sources of error in data links can be determined if the test results are compared with CCITT recommendations (Ml020 and V.S3) for data Transmission. The first chapter is a general overall survey of data communication links and computer networks. Chapter two discusses the effect of the transmission impairments on the data transmitted ~Gv~r analogue channels and the relation with the bit error rate, specially in the pres- ence of random and impuls\”e.noise. Chapter three is a review of the important performance tests and the theory of operation of some measuring equipments used to carry out the data tests. Chapter four is a practical application to determine the so~rces of error in two given examples. The first one tests the transmission impairments on an analogue microwave link. The source of data errors is the protection switching system. The second example is a switched line between two telephone exchanges. The source of data errors is the impulsivenoise Also, the correlation coefficient between impuls’~noise and bit error rate is calculated. At the end of the Chapter there is an example showing the implementation of a terminal to computer communication link. This link is one of the tested switched lines. Chapter five summarizes the results of all the tests conducted in all the experiments and how they can be applied to data communication links.. |