| At present the long distance transmission of digital signals is mainly dominated by fiber optic transmission. Compared with transmission with electrical signal on copper cable, transmission with optic signal on optic fiber has less attenuation, lower electromagnetic interference.But transmission with electrical signal can use the existing telephone network, wired television network, electric power network, the cost is much lower than the cost of reconstructing optical fiber network. On the other hand, because the optical fiber is fragile and can not bear big pulling force, high temperature and high pressure, in some applications, data transmission can only use the copper twisted-pair lying in the special-purpose electric cable, such as data transmission from mine shaft deep under the ground to control center on the ground in petroleum oil well logging. So it is still significant to study transmission of the electric signal remotely.At present studies of high speed electrical signals's long-line transmission are mianly based on ADSL technology; moreover our country has begin to study and test the application of Power Line Communication. In this thesis we we have thoroughly studied the related technologies by comparing and analyzing each kind of modulation and coding method, and have established a highly effective experimental system in this foundation.In First chapter, we establish twisted-pair's model and analyze long twisted-pair's channel characteristic, we first analyze the twisted-pair's model, then based on dual port network model [1, 2] and RLCG [1,2] model we analyze twisted-pair's (AWG #24,AWG #26) channel frequency spectrum characteristic, pulse response characteristic, signal to noise ratio and so on.Second chapter is about baseband transmission principle and baseband channel capacity. In this chapter we first introduce the signal's best receiving condition including the matched filter, the sampling non-distortion condition and the partial responses system. Then from the analysis of the channel error rate and the transmission efficiency, we point out how to choose the pulse forming signal and the system band width in the long twisted-pair's baseband transmission to realize the channel maximum capacity.In Third chapter, we analyze the realization method and the main technology of the baseband communication. We analyze the key technologies in baseband communication in detail, which include timing recovery and equalization of the signal mainly. Besides conventional timing recovery method, in order to solve the timing recovery question of likely the partial responses signal, we propose the method of using the higher nonlinear operation to obtain the timing recovery information.In Fourth chapter, we analyze twisted-pair wire's carrier communication method. We first analyze each kind of digital carrier modulation method. From signal to noise ratio analysis of the modulation signal, we choose the phase modulation method as the suitable carrier modulation for the twisted-pair. Then we specifically analyze the realization method of the QAM modulation on the twisted-pair channel including up-frequency-conversion, down-frequency-conversion, the phase estimation, the timing recovery, equalization and so on.Fifth chapter is about DMT multi-carriers technology. In this chapter we first analyze the process of the DMT modulation and demodulation and point out that the timing recovery and frequency and phase estimation, equalization in time domain, peek to average power ratio are the three main difficulties to be solved. Then we give out our solution. At last we analyze the maximum capacity of DMT modulation on the twisted-pair channel.Sixth chapter is about the error correcting code technology and concrete realization of twisted-pair communication.In Seventh chapter, we introduce the test system circuit and logic design of twisted-pair communication. In order to test the different modulation methods on the twisted-pair communication, we use FPGA to design a communication system whose structure can be...
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