M.Sc. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: In recent years, digital subscriber line (DSL) technology has been gaining popularity as a high speed access technology, as a main reason, this technology is capable of the delivering multimedia services. The major impairment for DSL technologies is crosstalk in the telephone lines. However, evaluating the data errors caused by this noise had not been well understood due to its complex statistical nature, and the complicated error mitigation and framing techniques had been used in DSL systems to overcome this noise effect. In this work, the crosstalk model of DSL lines is defined, and the effect of crosstalk on the channel capacity of ADSL services (the most widely used DSL service type) is investigated. In chapter one, it is emphasized on DSL technologies, and theoretical information is given about the modulation techniques,line properties, used frequency bands of verious different DSL services. It is is detaily emphasized on ADSL, the one of the widely used DSL service type, and the fundamental components of transmitter and receiver blocks of ADSL service are mainly examined as blocks. In chapter two, electrical parameters of the copper cables used to giving DSL services to subscribers are defined at the high frequencies. Crostalk, the major noise source for DSL services, first analytically examined, and crosstalk model dependent on frequency is formed. Next using this model, a simulation software which calculates the channel capacity of DSL lines under crosstalk effect is developed. Actuel ADSL lines are examined by using this software, and calculated values has been compared with measurement results made on real lines.
Keywords: DSL, Digital Subscriber Line, Crosstalk, Modelling, Simulation | |||||||||||||||||||||