Browsing by Author "John, Cleopa"

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    Modeling and analysis of digital equalizers for digital television systems.
    (University of Dar es Salaam, 2005) John, Cleopa
    Recently digital communication systems have become popular in various fields, since digital systems can provide high quality communication compared to convetional analog systems. However, transmited signals interfere with each other in communication channels due to the existence of delayed signals caused by multipath in radio transmission systems. These interferences are called intersymbol interference (ISI), which usually lead to degradation of quality of services. The devices to compensate for ISI are called equalizers (Lucky, Rudin, 1967). In this dissertation, three equalizers are modeled and analyzed for use in a digital television (TV) system known as High Definition Television (HDTV). These equalizers are Decision Feedback Equalizer (DFE), Adaptive Decision Feedback Equalizer (ADFE) and blind equalizer. The simulation results show that, the DFE which is currently the equalizer in use with the HDTV system, performed poorly compared with the other two suggested equalizers in two performance metrics: the eye diagram and the probability of symbol error. However, using the same criteria, the blind equalizer outperforms all the other two equalizers.