【作者】 丁来伟；

【导师】 贺利洁；

【作者基本信息】 西安电子科技大学 ， 电路与系统， 2002， 硕士

【摘要】 信息产业的飞速发展，尤其是因特网的普遍应用，使宽带化成为接入网的发展趋势。非对称数字用户环路(ADSL)技术以充分利用现有双绞线资源的潜力为出发点，在不影响电话业务的同时，提供高速、非对称的数据接入。作为多载波调制的一种实现形式，离散多音频(DMT)调制分别采用逆傅立叶变换矢量和傅立叶变换矢量作为调制矢量和解调矢量，从而调制和解调过程可以利用这两种变换的快速算法实现。它根据各个子信道信噪比的情况确定其传送比特数，由噪声引起的干扰功率被分散到各个子信道中，降低了其引起的干扰。RS编码和交织技术的结合，更能纠正较长的突发错误或多个突发错误，进一步提高了系统的性能。论文根据理论研究给出了ADSL接入系统的局端设备——数字用户环路接入复用器(DSLAM)的设计及实现。实际系统的各项指标测试有力地证实了ADSL技术的实用性。更多还原

【Abstract】 With the rapid development of Information Technology(IT), especially the universal application of Internet, broadband Access Networks(AN) become more and more prevalent. Asymmetric Digital Subscriber Loop(ADSL) is the technology that provides high-speed, asymmetric data access, synchronously the potential of Twisted Pair(TP) is utilized, and the Plain Old Telephone Service(POTS) is not interrupted. As an implementing method of Multi-Carrier Modulation(MCM), Discrete Multi-Tone (DMT) modulation uses Inverse Discrete Fourier Transform(IDFT) vector as its modulating vector, and Discrete" Fourier Transibrm(DFT) vector as its demodulating vector, and the process of modulating and demodulating can be realized by using their fast calculating method. Bits transmitted by every subchannel are determined by its value of Signal to Noise Ratio(SNR), and the unwanted power caused by noise is distributed to every subchannel, so their damage is weakened. In addition, Reed-Solomon(RS) coding and interleaving are applied to correct long outburst error, so the performance of the system is enhanced once more. Based on theoretical research, the article expounds the project and implement of Digital Subscriber Loop Access Multiplexer(DSLAM)-central office equipment of ADSL system. And the practical testing result effectively proves the practicality of ADSL.更多还原